| blob | 9492fff6b0d354cca3f1d9a741cbb46156111783 |
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- S E M _ R E S --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2015, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
20 -- --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
23 -- --
24 ------------------------------------------------------------------------------
86 -----------------------
87 -- Local Subprograms --
88 -----------------------
90 -- Second pass (top-down) type checking and overload resolution procedures
91 -- Typ is the type required by context. These procedures propagate the
92 -- type information recursively to the descendants of N. If the node is not
93 -- overloaded, its Etype is established in the first pass. If overloaded,
94 -- the Resolve routines set the correct type. For arithmetic operators, the
95 -- Etype is the base type of the context.
97 -- Note that Resolve_Attribute is separated off in Sem_Attr
100 -- Enforce the restrictions on the use of discriminants when constraining
101 -- a component of a discriminated type (record or concurrent type).
104 -- Given a node for an operator associated with type T, check that the
105 -- operator is visible. Operators all of whose operands are universal must
106 -- be checked for visibility during resolution because their type is not
107 -- determinable based on their operands.
109 procedure Check_Fully_Declared_Prefix
112 -- Check that the type of the prefix of a dereference is not incomplete
115 -- Given a call node, N, which is known to occur immediately within the
116 -- subprogram being called, determines whether it is a detectable case of
117 -- an infinite recursion, and if so, outputs appropriate messages. Returns
118 -- True if an infinite recursion is detected, and False otherwise.
121 -- If the type of the object being initialized uses the secondary stack
122 -- directly or indirectly, create a transient scope for the call to the
123 -- init proc. This is because we do not create transient scopes for the
124 -- initialization of individual components within the init proc itself.
125 -- Could be optimized away perhaps?
128 -- N is the node for a logical operator. If the operator is predefined, and
129 -- the root type of the operands is Standard.Boolean, then a check is made
130 -- for restriction No_Direct_Boolean_Operators. This procedure also handles
131 -- the style check for Style_Check_Boolean_And_Or.
134 -- N is either an indexed component or a selected component. This function
135 -- returns true if the prefix refers to an object that has an address
136 -- clause (the case in which we may want to issue a warning).
139 -- Determine whether E is an access type declared by an access declaration,
140 -- and not an (anonymous) allocator type.
143 -- Utility to check whether the entity for an operator is a predefined
144 -- operator, in which case the expression is left as an operator in the
145 -- tree (else it is rewritten into a call). An instance of an intrinsic
146 -- conversion operation may be given an operator name, but is not treated
147 -- like an operator. Note that an operator that is an imported back-end
148 -- builtin has convention Intrinsic, but is expected to be rewritten into
149 -- a call, so such an operator is not treated as predefined by this
150 -- predicate.
153 -- If a default expression in entry call N depends on the discriminants
154 -- of the task, it must be replaced with a reference to the discriminant
155 -- of the task being called.
157 procedure Resolve_Op_Concat_Arg
162 -- Internal procedure for Resolve_Op_Concat to resolve one operand of
163 -- concatenation operator. The operand is either of the array type or of
164 -- the component type. If the operand is an aggregate, and the component
165 -- type is composite, this is ambiguous if component type has aggregates.
168 -- Does the first part of the work of Resolve_Op_Concat
171 -- Does the "rest" of the work of Resolve_Op_Concat, after the left operand
172 -- has been resolved. See Resolve_Op_Concat for details.
210 function Operator_Kind
213 -- Utility to map the name of an operator into the corresponding Node. Used
214 -- by other node rewriting procedures.
217 -- Resolve actuals of call, and add default expressions for missing ones.
218 -- N is the Node_Id for the subprogram call, and Nam is the entity of the
219 -- called subprogram.
222 -- Called from Resolve_Call, when the prefix denotes an entry or element
223 -- of entry family. Actuals are resolved as for subprograms, and the node
224 -- is rebuilt as an entry call. Also called for protected operations. Typ
225 -- is the context type, which is used when the operation is a protected
226 -- function with no arguments, and the return value is indexed.
229 -- A call to a user-defined intrinsic operator is rewritten as a call to
230 -- the corresponding predefined operator, with suitable conversions. Note
231 -- that this applies only for intrinsic operators that denote predefined
232 -- operators, not ones that are intrinsic imports of back-end builtins.
235 -- Ditto, for arithmetic unary operators
238 -- If an operator node resolves to a call to a user-defined operator,
239 -- rewrite the node as a function call.
241 procedure Make_Call_Into_Operator
245 -- Inverse transformation: if an operator is given in functional notation,
246 -- then after resolving the node, transform into an operator node, so that
247 -- operands are resolved properly. Recall that predefined operators do not
248 -- have a full signature and special resolution rules apply.
250 procedure Rewrite_Renamed_Operator
254 -- An operator can rename another, e.g. in an instantiation. In that
255 -- case, the proper operator node must be constructed and resolved.
258 -- The String_Literal_Subtype is built for all strings that are not
259 -- operands of a static concatenation operation. If the argument is not
260 -- a N_String_Literal node, then the call has no effect.
263 -- Build subtype of array type, with the range specified by the slice
266 -- Called after N has been resolved and evaluated, but before range checks
267 -- have been applied. Currently simplifies a combination of floating-point
268 -- to integer conversion and Rounding or Truncation attribute.
271 -- A universal_fixed expression in an universal context is unambiguous if
272 -- there is only one applicable fixed point type. Determining whether there
273 -- is only one requires a search over all visible entities, and happens
274 -- only in very pathological cases (see 6115-006).
276 -------------------------
277 -- Ambiguous_Character --
278 -------------------------
283 begin
287 -- First the ones in Standard
292 -- Include Wide_Wide_Character in Ada 2005 mode
298 -- Now any other types that match
308 -------------------------
309 -- Analyze_And_Resolve --
310 -------------------------
313 begin
319 begin
324 -- Versions with check(s) suppressed
326 procedure Analyze_And_Resolve
330 is
333 begin
335 declare
337 begin
343 else
344 declare
346 begin
354 and then Scope_Is_Transient
355 then
356 -- This can only happen if a transient scope was created for an inner
357 -- expression, which will be removed upon completion of the analysis
358 -- of an enclosing construct. The transient scope must have the
359 -- suppress status of the enclosing environment, not of this Analyze
360 -- call.
363 Scope_Suppress;
367 procedure Analyze_And_Resolve
370 is
373 begin
375 declare
377 begin
383 else
384 declare
386 begin
395 Scope_Suppress;
399 ----------------------------
400 -- Check_Discriminant_Use --
401 ----------------------------
409 begin
410 -- Any use in a spec-expression is legal
417 -- Discriminant cannot be used to constrain a scalar type
424 then
429 -- The following check catches the unusual case where a
430 -- discriminant appears within an index constraint that is part
431 -- of a larger expression within a constraint on a component,
432 -- e.g. "C : Int range 1 .. F (new A(1 .. D))". For now we only
433 -- check case of record components, and note that a similar check
434 -- should also apply in the case of discriminant constraints
435 -- below. ???
437 -- Note that the check for N_Subtype_Declaration below is to
438 -- detect the valid use of discriminants in the constraints of a
439 -- subtype declaration when this subtype declaration appears
440 -- inside the scope of a record type (which is syntactically
441 -- illegal, but which may be created as part of derived type
442 -- processing for records). See Sem_Ch3.Build_Derived_Record_Type
443 -- for more info.
447 and then not
449 and then
451 N_Subtype_Declaration)
453 then
454 Error_Msg_N
459 -- Detect a common error:
461 -- type R (D : Positive := 100) is record
462 -- Name : String (1 .. D);
463 -- end record;
465 -- The default value causes an object of type R to be allocated
466 -- with room for Positive'Last characters. The RM does not mandate
467 -- the allocation of the maximum size, but that is what GNAT does
468 -- so we should warn the programmer that there is a problem.
477 -- Return True if type T has a large enough range that any
478 -- array whose index type covered the whole range of the type
479 -- would likely raise Storage_Error.
481 ------------------------
482 -- Large_Storage_Type --
483 ------------------------
486 begin
487 -- The type is considered large if its bounds are known at
488 -- compile time and if it requires at least as many bits as
489 -- a Positive to store the possible values.
493 and then
498 -- Start of processing for Check_Large
500 begin
501 -- Check that the Disc has a large range
507 -- If the enclosing type is limited, we allocate only the
508 -- default value, not the maximum, and there is no need for
509 -- a warning.
515 -- Check that it is the high bound
519 then
523 -- Check the array allows a large range at this bound. First
524 -- find the array
538 -- Next, find the dimension
546 loop
555 -- Now, check the dimension has a large range
561 -- Warn about the danger
563 Error_Msg_N
573 -- Legal case is in index or discriminant constraint
576 N_Discriminant_Association)
577 then
579 Error_Msg_N
584 then
585 Error_Msg_N
591 -- Otherwise, context is an expression. It should not be within (i.e. a
592 -- subexpression of) a constraint for a component.
594 else
598 N_Subtype_Indication,
599 N_Entry_Declaration)
600 loop
606 -- If the discriminant is used in an expression that is a bound of a
607 -- scalar type, an Itype is created and the bounds are attached to
608 -- its range, not to the original subtype indication. Such use is of
609 -- course a double fault.
613 N_Derived_Type_Definition)
616 -- The constraint itself may be given by a subtype indication,
617 -- rather than by a more common discrete range.
620 and then
624 then
625 Error_Msg_N
631 --------------------------------
632 -- Check_For_Visible_Operator --
633 --------------------------------
636 begin
638 Error_Msg_NE -- CODEFIX
640 Error_Msg_N -- CODEFIX
645 ----------------------------------
646 -- Check_Fully_Declared_Prefix --
647 ----------------------------------
649 procedure Check_Fully_Declared_Prefix
652 is
653 begin
654 -- Check that the designated type of the prefix of a dereference is
655 -- not an incomplete type. This cannot be done unconditionally, because
656 -- dereferences of private types are legal in default expressions. This
657 -- case is taken care of in Check_Fully_Declared, called below. There
658 -- are also 2005 cases where it is legal for the prefix to be unfrozen.
660 -- This consideration also applies to similar checks for allocators,
661 -- qualified expressions, and type conversions.
663 -- An additional exception concerns other per-object expressions that
664 -- are not directly related to component declarations, in particular
665 -- representation pragmas for tasks. These will be per-object
666 -- expressions if they depend on discriminants or some global entity.
667 -- If the task has access discriminants, the designated type may be
668 -- incomplete at the point the expression is resolved. This resolution
669 -- takes place within the body of the initialization procedure, where
670 -- the discriminant is replaced by its discriminal.
674 then
677 -- Ada 2005 (AI-326): Tagged incomplete types allowed. The wrong usages
678 -- are handled by Analyze_Access_Attribute, Analyze_Assignment,
679 -- Analyze_Object_Renaming, and Freeze_Entity.
685 E_Incomplete_Type
687 then
689 else
694 ------------------------------
695 -- Check_Infinite_Recursion --
696 ------------------------------
703 -- Check whether list of actuals is identical to list of formals of
704 -- called function (which is also the enclosing scope).
706 ------------------------
707 -- Same_Argument_List --
708 ------------------------
715 begin
718 else
736 -- Start of processing for Check_Infinite_Recursion
738 begin
739 -- Special case, if this is a procedure call and is a call to the
740 -- current procedure with the same argument list, then this is for
741 -- sure an infinite recursion and we insert a call to raise SE.
745 and then Same_Argument_List
746 then
747 declare
749 begin
753 then
765 -- If not that special case, search up tree, quitting if we reach a
766 -- construct (e.g. a conditional) that tells us that this is not a
767 -- case for an infinite recursion warning.
770 loop
773 -- If no parent, then we were not inside a subprogram, this can for
774 -- example happen when processing certain pragmas in a spec. Just
775 -- return False in this case.
781 -- Done if we get to subprogram body, this is definitely an infinite
782 -- recursion case if we did not find anything to stop us.
786 -- If appearing in conditional, result is false
789 N_And_Then,
790 N_Case_Expression,
791 N_Case_Statement,
792 N_If_Expression,
793 N_If_Statement)
794 then
799 then
800 -- If the call is the expression of a return statement and the
801 -- actuals are identical to the formals, it's worth a warning.
802 -- However, we skip this if there is an immediately preceding
803 -- raise statement, since the call is never executed.
805 -- Furthermore, this corresponds to a common idiom:
807 -- function F (L : Thing) return Boolean is
808 -- begin
809 -- raise Program_Error;
810 -- return F (L);
811 -- end F;
813 -- for generating a stub function
816 and then Same_Argument_List
817 then
820 -- OK, return statement is in a statement list, look for raise
822 declare
825 begin
826 -- Skip past N_Freeze_Entity nodes generated by expansion
831 loop
835 -- If no raise statement, give warning. We look at the
836 -- original node, because in the case of "raise ... with
837 -- ...", the node has been transformed into a call.
840 and then
848 else
860 -------------------------------
861 -- Check_Initialization_Call --
862 -------------------------------
868 -- Check whether the creation of an object of the type will involve
869 -- use of the secondary stack. If T is a record type, this is true
870 -- if the expression for some component uses the secondary stack, e.g.
871 -- through a call to a function that returns an unconstrained value.
872 -- False if T is controlled, because cleanups occur elsewhere.
874 -------------
875 -- Uses_SS --
876 -------------
883 begin
884 -- Normally we want to use the underlying type, but if it's not set
885 -- then continue with T.
902 then
903 -- The expression for a dynamic component may be rewritten
904 -- as a dereference, so retrieve original node.
908 -- Return True if the expression is a call to a function
909 -- (including an attribute function such as Image, or a
910 -- user-defined operator) with a result that requires a
911 -- transient scope.
918 then
931 else
936 -- Start of processing for Check_Initialization_Call
938 begin
939 -- Establish a transient scope if the type needs it
946 ---------------------------------------
947 -- Check_No_Direct_Boolean_Operators --
948 ---------------------------------------
951 begin
954 then
955 -- Restriction only applies to original source code
962 -- Do style check (but skip if in instance, error is on template)
971 ------------------------------
972 -- Check_Parameterless_Call --
973 ------------------------------
979 -- If the prefix is of an access_to_subprogram type, the node must be
980 -- rewritten as a call. Ditto if the prefix is overloaded and all its
981 -- interpretations are access to subprograms.
983 ---------------------------
984 -- Prefix_Is_Access_Subp --
985 ---------------------------
991 begin
992 -- If the context is an attribute reference that can apply to
993 -- functions, this is never a parameterless call (RM 4.1.4(6)).
997 Name_Code_Address,
998 Name_Access)
999 then
1004 return
1007 else
1012 then
1023 -- Start of processing for Check_Parameterless_Call
1025 begin
1026 -- Defend against junk stuff if errors already detected
1033 then
1040 -- If the context expects a value, and the name is a procedure, this is
1041 -- most likely a missing 'Access. Don't try to resolve the parameterless
1042 -- call, error will be caught when the outer call is analyzed.
1047 and then
1049 N_Function_Call,
1050 N_Procedure_Call_Statement)
1051 then
1055 -- Rewrite as call if overloadable entity that is (or could be, in the
1056 -- overloaded case) a function call. If we know for sure that the entity
1057 -- is an enumeration literal, we do not rewrite it.
1059 -- If the entity is the name of an operator, it cannot be a call because
1060 -- operators cannot have default parameters. In this case, this must be
1061 -- a string whose contents coincide with an operator name. Set the kind
1062 -- of the node appropriately.
1070 -- Rewrite as call if it is an explicit dereference of an expression of
1071 -- a subprogram access type, and the subprogram type is not that of a
1072 -- procedure or entry.
1074 or else
1077 -- Rewrite as call if it is a selected component which is a function,
1078 -- this is the case of a call to a protected function (which may be
1079 -- overloaded with other protected operations).
1081 or else
1084 or else
1086 E_Procedure)
1089 -- If one of the above three conditions is met, rewrite as call. Apply
1090 -- the rewriting only once.
1092 then
1095 then
1097 -- This may be a prefixed call that was not fully analyzed, e.g.
1098 -- an actual in an instance.
1103 then
1111 -- The node is the name of the parameterless call. Preserve its
1112 -- descendants, which may be complex expressions.
1116 -- If overloaded, overload set belongs to new copy
1120 -- Change node to parameterless function call (note that the
1121 -- Parameter_Associations associations field is left set to Empty,
1122 -- its normal default value since there are no parameters)
1140 --------------------------------
1141 -- Is_Atomic_Ref_With_Address --
1142 --------------------------------
1147 begin
1151 else
1152 declare
1155 begin
1163 -----------------------------
1164 -- Is_Definite_Access_Type --
1165 -----------------------------
1169 begin
1175 ----------------------
1176 -- Is_Predefined_Op --
1177 ----------------------
1180 begin
1181 -- Predefined operators are intrinsic subprograms
1187 -- A call to a back-end builtin is never a predefined operator
1198 -----------------------------
1199 -- Make_Call_Into_Operator --
1200 -----------------------------
1202 procedure Make_Call_Into_Operator
1206 is
1221 -- If the operand is not universal, and the operator is given by an
1222 -- expanded name, verify that the operand has an interpretation with a
1223 -- type defined in the given scope of the operator.
1226 -- Find a type of the given class in package Pack that contains the
1227 -- operator.
1229 ---------------------------
1230 -- Operand_Type_In_Scope --
1231 ---------------------------
1238 begin
1242 else
1256 ---------------
1257 -- Type_In_P --
1258 ---------------
1264 -- Verify that node is not part of the type declaration for the
1265 -- candidate type, which would otherwise be invisible.
1267 -------------
1268 -- In_Decl --
1269 -------------
1275 begin
1284 else
1287 loop
1290 else
1299 -- Start of processing for Type_In_P
1301 begin
1302 -- If the context type is declared in the prefix package, this is the
1303 -- desired base type.
1308 else
1322 -- Start of processing for Make_Call_Into_Operator
1324 begin
1327 -- Binary operator
1337 -- Unary operator
1339 else
1345 -- If the operator is denoted by an expanded name, and the prefix is
1346 -- not Standard, but the operator is a predefined one whose scope is
1347 -- Standard, then this is an implicit_operator, inserted as an
1348 -- interpretation by the procedure of the same name. This procedure
1349 -- overestimates the presence of implicit operators, because it does
1350 -- not examine the type of the operands. Verify now that the operand
1351 -- type appears in the given scope. If right operand is universal,
1352 -- check the other operand. In the case of concatenation, either
1353 -- argument can be the component type, so check the type of the result.
1354 -- If both arguments are literals, look for a type of the right kind
1355 -- defined in the given scope. This elaborate nonsense is brought to
1356 -- you courtesy of b33302a. The type itself must be frozen, so we must
1357 -- find the type of the proper class in the given scope.
1359 -- A final wrinkle is the multiplication operator for fixed point types,
1360 -- which is defined in Standard only, and not in the scope of the
1361 -- fixed point type itself.
1366 -- If this is a package renaming, get renamed entity, which will be
1367 -- the scope of the operands if operaton is type-correct.
1373 -- If the entity being called is defined in the given package, it is
1374 -- a renaming of a predefined operator, and known to be legal.
1378 then
1381 -- Visibility does not need to be checked in an instance: if the
1382 -- operator was not visible in the generic it has been diagnosed
1383 -- already, else there is an implicit copy of it in the instance.
1391 then
1396 -- Ada 2005 AI-420: Predefined equality on Universal_Access is
1397 -- available.
1402 then
1405 else
1414 and then Is_Binary
1416 then
1422 -- Verify that the scope contains a type that corresponds to
1423 -- the given literal. Optimize the case where Pack is Standard.
1445 else
1454 else
1463 then
1466 -- If the type is defined elsewhere, and the operator is not
1467 -- defined in the given scope (by a renaming declaration, e.g.)
1468 -- then this is an error as well. If an extension of System is
1469 -- present, and the type may be defined there, Pack must be
1470 -- System itself.
1477 then
1480 else
1486 then
1493 Error_Msg_NE
1498 -- Detect a mismatch between the context type and the result type
1499 -- in the named package, which is otherwise not detected if the
1500 -- operands are universal. Check is only needed if source entity is
1501 -- an operator, not a function that renames an operator.
1508 and then not In_Instance
1509 then
1512 then
1513 -- Already checked above
1517 -- Operator may be defined in an extension of System
1521 then
1524 else
1525 -- Could we use Wrong_Type here??? (this would require setting
1526 -- Etype (N) to the actual type found where Typ was expected).
1537 else
1541 -- If this is a call to a function that renames a predefined equality,
1542 -- the renaming declaration provides a type that must be used to
1543 -- resolve the operands. This must be done now because resolution of
1544 -- the equality node will not resolve any remaining ambiguity, and it
1545 -- assumes that the first operand is not overloaded.
1550 then
1558 -- Do rewrite setting Comes_From_Source on the result if the original
1559 -- call came from source. Although it is not strictly the case that the
1560 -- operator as such comes from the source, logically it corresponds
1561 -- exactly to the function call in the source, so it should be marked
1562 -- this way (e.g. to make sure that validity checks work fine).
1564 declare
1566 begin
1571 -- If this is an arithmetic operator and the result type is private,
1572 -- the operands and the result must be wrapped in conversion to
1573 -- expose the underlying numeric type and expand the proper checks,
1574 -- e.g. on division.
1578 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
1579 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
1588 else
1592 -- If in ASIS_Mode, propagate operand types to original actuals of
1593 -- function call, which would otherwise not be fully resolved. If
1594 -- the call has already been constant-folded, nothing to do. We
1595 -- relocate the operand nodes rather than copy them, to preserve
1596 -- original_node pointers, given that the operands themselves may
1597 -- have been rewritten. If the call was itself a rewriting of an
1598 -- operator node, nothing to do.
1600 if ASIS_Mode
1603 then
1604 declare
1612 begin
1617 -- If the original call has named associations, replace the
1618 -- explicit actual parameter in the association with the proper
1619 -- resolved operand.
1624 then
1627 else
1632 else
1639 then
1642 else
1647 else
1651 else
1655 else
1665 -------------------
1666 -- Operator_Kind --
1667 -------------------
1669 function Operator_Kind
1672 is
1675 begin
1676 -- Use CASE statement or array???
1713 else
1717 -- Unary operators
1719 else
1728 else
1736 ----------------------------
1737 -- Preanalyze_And_Resolve --
1738 ----------------------------
1743 begin
1747 -- Normally, we suppress all checks for this preanalysis. There is no
1748 -- point in processing them now, since they will be applied properly
1749 -- and in the proper location when the default expressions reanalyzed
1750 -- and reexpanded later on. We will also have more information at that
1751 -- point for possible suppression of individual checks.
1753 -- However, in SPARK mode, most expansion is suppressed, and this
1754 -- later reanalysis and reexpansion may not occur. SPARK mode does
1755 -- require the setting of checking flags for proof purposes, so we
1756 -- do the SPARK preanalysis without suppressing checks.
1758 -- This special handling for SPARK mode is required for example in the
1759 -- case of Ada 2012 constructs such as quantified expressions, which are
1760 -- expanded in two separate steps.
1764 else
1768 Expander_Mode_Restore;
1772 -- Version without context type
1777 begin
1784 Expander_Mode_Restore;
1788 ----------------------------------
1789 -- Replace_Actual_Discriminants --
1790 ----------------------------------
1797 -- Comment needed???
1799 -------------------
1800 -- Process_Discr --
1801 -------------------
1806 begin
1812 then
1828 -- Start of processing for Replace_Actual_Discriminants
1830 begin
1844 else
1849 -------------
1850 -- Resolve --
1851 -------------
1867 -- Determine whether a node comes from a predefined library unit or
1868 -- Standard.
1871 -- Try and fix up a literal so that it matches its expected type. New
1872 -- literals are manufactured if necessary to avoid cascaded errors.
1875 -- Additional diagnostics when an ambiguous call has an ambiguous
1876 -- argument (typically a controlling actual).
1879 -- Called when attempt at resolving current expression fails
1881 ------------------------------------
1882 -- Comes_From_Predefined_Lib_Unit --
1883 -------------------------------------
1886 begin
1887 return
1889 or else Is_Predefined_File_Name
1893 --------------------
1894 -- Patch_Up_Value --
1895 --------------------
1898 begin
1915 then
1920 Char_Literal_Value =>
1936 -------------------------------
1937 -- Report_Ambiguous_Argument --
1938 -------------------------------
1945 begin
1949 then
1952 -- Could use comments on what is going on here???
1960 else
1969 -----------------------
1970 -- Resolution_Failed --
1971 -----------------------
1974 begin
1980 -- The caller will return without calling the expander, so we need
1981 -- to set the analyzed flag. Note that it is fine to set Analyzed
1982 -- to True even if we are in the middle of a shallow analysis,
1983 -- (see the spec of sem for more details) since this is an error
1984 -- situation anyway, and there is no point in repeating the
1985 -- analysis later (indeed it won't work to repeat it later, since
1986 -- we haven't got a clear resolution of which entity is being
1987 -- referenced.)
1993 -- Start of processing for Resolve
1995 begin
2000 -- Access attribute on remote subprogram cannot be used for a non-remote
2001 -- access-to-subprogram type.
2005 Name_Unrestricted_Access,
2006 Name_Unchecked_Access)
2012 then
2013 Error_Msg_N
2019 -- If the context is a Remote_Access_To_Subprogram, access attributes
2020 -- must be resolved with the corresponding fat pointer. There is no need
2021 -- to check for the attribute name since the return type of an
2022 -- attribute is never a remote type.
2027 then
2028 declare
2036 begin
2037 -- Check that Typ is a remote access-to-subprogram type
2041 -- Prefix (N) must statically denote a remote subprogram
2042 -- declared in a package specification.
2046 Attr = Attribute_Unrestricted_Access
2047 then
2062 or else
2064 then
2066 Error_Msg_N
2068 N);
2071 -- If we are generating code in distributed mode, perform
2072 -- semantic checks against corresponding remote entities.
2074 if Expander_Active
2076 then
2077 Check_Subtype_Conformant
2079 Old_Id => Designated_Type
2105 then
2110 -- Return if already analyzed
2117 -- Any case of Any_Type as the Etype value means that we had a
2118 -- previous error.
2127 -- The resolution of an Expression_With_Actions is determined by
2128 -- its Expression.
2136 -- If not overloaded, then we know the type, and all that needs doing
2137 -- is to check that this type is compatible with the context.
2143 -- In the overloaded case, we must select the interpretation that
2144 -- is compatible with the context (i.e. the type passed to Resolve)
2146 else
2147 -- Loop through possible interpretations
2156 -- We are only interested in interpretations that are compatible
2157 -- with the expected type, any other interpretations are ignored.
2162 Write_Eol;
2165 else
2166 -- Skip the current interpretation if it is disabled by an
2167 -- abstract operator. This action is performed only when the
2168 -- type against which we are resolving is the same as the
2169 -- type of the interpretation.
2176 then
2184 -- First matching interpretation
2192 -- Matching interpretation that is not the first, maybe an
2193 -- error, but there are some cases where preference rules are
2194 -- used to choose between the two possibilities. These and
2195 -- some more obscure cases are handled in Disambiguate.
2197 else
2198 -- If the current statement is part of a predefined library
2199 -- unit, then all interpretations which come from user level
2200 -- packages should not be considered. Check previous and
2201 -- current one.
2209 -- Previous interpretation must be discarded
2219 -- Otherwise apply further disambiguation steps
2224 -- Disambiguation has succeeded. Skip the remaining
2225 -- interpretations.
2235 else
2236 -- Before we issue an ambiguity complaint, check for
2237 -- the case of a subprogram call where at least one
2238 -- of the arguments is Any_Type, and if so, suppress
2239 -- the message, since it is a cascaded error.
2242 declare
2246 begin
2258 Write_Eol;
2271 then
2276 then
2280 -- Not that special case, so issue message using the
2281 -- flag Ambiguous to control printing of the header
2282 -- message only at the start of an ambiguous set.
2287 then
2288 Error_Msg_N
2291 else
2292 Error_Msg_NE -- CODEFIX
2300 Error_Msg_N
2302 else
2303 Error_Msg_N -- CODEFIX
2309 then
2310 Report_Ambiguous_Argument;
2316 -- By default, the error message refers to the candidate
2317 -- interpretation. But if it is a predefined operator, it
2318 -- is implicitly declared at the declaration of the type
2319 -- of the operand. Recover the sloc of that declaration
2320 -- for the error message.
2326 Standard_Standard
2327 then
2332 then
2340 Standard_Standard
2341 then
2346 then
2350 -- If this is an indirect call, use the subprogram_type
2351 -- in the message, to have a meaningful location. Also
2352 -- indicate if this is an inherited operation, created
2353 -- by a type declaration.
2358 then
2360 Error_Msg_Sloc :=
2362 else
2369 then
2370 -- Special-case the message for universal_fixed
2371 -- operators, which are not declared with the type
2372 -- of the operand, but appear forever in Standard.
2376 then
2377 Error_Msg_N
2380 else
2381 Error_Msg_N
2385 elsif
2387 then
2388 Error_Msg_N
2390 else
2391 Error_Msg_N -- CODEFIX
2398 -- We have a matching interpretation, Expr_Type is the type
2399 -- from this interpretation, and Seen is the entity.
2401 -- For an operator, just set the entity name. The type will be
2402 -- set by the specific operator resolution routine.
2417 -- AI05-0139-2: Expression is overloaded because type has
2418 -- implicit dereference. If type matches context, no implicit
2419 -- dereference is involved.
2430 then
2431 -- If the node is a general indexing, the dereference is
2432 -- is inserted when resolving the rewritten form, else
2433 -- insert it now.
2437 then
2441 -- For an explicit dereference, attribute reference, range,
2442 -- short-circuit form (which is not an operator node), or call
2443 -- with a name that is an explicit dereference, there is
2444 -- nothing to be done at this point.
2447 N_Attribute_Reference,
2448 N_And_Then,
2449 N_Indexed_Component,
2450 N_Or_Else,
2451 N_Range,
2452 N_Selected_Component,
2453 N_Slice)
2455 then
2458 -- For procedure or function calls, set the type of the name,
2459 -- and also the entity pointer for the prefix.
2463 then
2470 then
2475 -- For all other cases, just set the type of the Name
2477 else
2485 -- Move to next interpretation
2493 -- At this stage Found indicates whether or not an acceptable
2494 -- interpretation exists. If not, then we have an error, except that if
2495 -- the context is Any_Type as a result of some other error, then we
2496 -- suppress the error report.
2501 -- If type we are looking for is Void, then this is the procedure
2502 -- call case, and the error is simply that what we gave is not a
2503 -- procedure name (we think of procedure calls as expressions with
2504 -- types internally, but the user doesn't think of them this way).
2508 -- Special case message if function used as a procedure
2513 then
2514 Error_Msg_NE
2518 -- Otherwise give general message (not clear what cases this
2519 -- covers, but no harm in providing for them).
2521 else
2527 -- Otherwise we do have a subexpression with the wrong type
2529 -- Check for the case of an allocator which uses an access type
2530 -- instead of the designated type. This is a common error and we
2531 -- specialize the message, posting an error on the operand of the
2532 -- allocator, complaining that we expected the designated type of
2533 -- the allocator.
2539 then
2543 -- Check for view mismatch on Null in instances, for which the
2544 -- view-swapping mechanism has no identifier.
2550 then
2555 -- Check for an aggregate. Sometimes we can get bogus aggregates
2556 -- from misuse of parentheses, and we are about to complain about
2557 -- the aggregate without even looking inside it.
2559 -- Instead, if we have an aggregate of type Any_Composite, then
2560 -- analyze and resolve the component fields, and then only issue
2561 -- another message if we get no errors doing this (otherwise
2562 -- assume that the errors in the aggregate caused the problem).
2566 then
2567 -- Disable expansion in any case. If there is a type mismatch
2568 -- it may be fatal to try to expand the aggregate. The flag
2569 -- would otherwise be set to false when the error is posted.
2573 declare
2575 -- Check one aggregate, and set Found to True if we have a
2576 -- definite error in any of its elements
2579 -- Check one element of aggregate and set Found to True if
2580 -- we definitely have an error in the element.
2582 ----------------
2583 -- Check_Aggr --
2584 ----------------
2589 begin
2602 -- If this is a default-initialized component, then
2603 -- there is nothing to check. The box will be
2604 -- replaced by the appropriate call during late
2605 -- expansion.
2616 ----------------
2617 -- Check_Elmt --
2618 ----------------
2621 begin
2622 -- If we have a nested aggregate, go inside it (to
2623 -- attempt a naked analyze-resolve of the aggregate can
2624 -- cause undesirable cascaded errors). Do not resolve
2625 -- expression if it needs a type from context, as for
2626 -- integer * fixed expression.
2631 else
2636 then
2646 begin
2651 -- Looks like we have a type error, but check for special case
2652 -- of Address wanted, integer found, with the configuration pragma
2653 -- Allow_Integer_Address active. If we have this case, introduce
2654 -- an unchecked conversion to allow the integer expression to be
2655 -- treated as an Address. The reverse case of integer wanted,
2656 -- Address found, is treated in an analogous manner.
2664 -- That special Allow_Integer_Address check did not appply, so we
2665 -- have a real type error. If an error message was issued already,
2666 -- Found got reset to True, so if it's still False, issue standard
2667 -- Wrong_Type message.
2671 declare
2674 begin
2680 -- Protected operation: retrieve operation name
2684 else
2689 Error_Msg_NE
2695 declare
2699 begin
2706 Error_Msg_NE
2712 else
2716 else
2722 Resolution_Failed;
2725 -- Test if we have more than one interpretation for the context
2728 Resolution_Failed;
2731 -- Only one intepretation
2733 else
2734 -- In Ada 2005, if we have something like "X : T := 2 + 2;", where
2735 -- the "+" on T is abstract, and the operands are of universal type,
2736 -- the above code will have (incorrectly) resolved the "+" to the
2737 -- universal one in Standard. Therefore check for this case and give
2738 -- an error. We can't do this earlier, because it would cause legal
2739 -- cases to get errors (when some other type has an abstract "+").
2745 then
2750 then
2751 Error_Msg_NE
2760 -- Here we have an acceptable interpretation for the context
2762 -- Propagate type information and normalize tree for various
2763 -- predefined operations. If the context only imposes a class of
2764 -- types, rather than a specific type, propagate the actual type
2765 -- downward.
2771 Typ = Any_Discrete
2772 then
2775 -- Any_Fixed is legal in a real context only if a specific fixed-
2776 -- point type is imposed. If Norman Cohen can be confused by this,
2777 -- it deserves a separate message.
2781 then
2788 -- A user-defined operator is transformed into a function call at
2789 -- this point, so that further processing knows that operators are
2790 -- really operators (i.e. are predefined operators). User-defined
2791 -- operators that are intrinsic are just renamings of the predefined
2792 -- ones, and need not be turned into calls either, but if they rename
2793 -- a different operator, we must transform the node accordingly.
2794 -- Instantiations of Unchecked_Conversion are intrinsic but are
2795 -- treated as functions, even if given an operator designator.
2800 then
2806 and then
2808 N_Subprogram_Renaming_Declaration
2809 then
2812 -- If the node is rewritten, it will be fully resolved in
2813 -- Rewrite_Renamed_Operator.
2823 when N_Aggregate => Resolve_Aggregate (N, Ctx_Type);
2825 when N_Allocator => Resolve_Allocator (N, Ctx_Type);
2827 when N_Short_Circuit
2828 => Resolve_Short_Circuit (N, Ctx_Type);
2830 when N_Attribute_Reference
2831 => Resolve_Attribute (N, Ctx_Type);
2833 when N_Case_Expression
2834 => Resolve_Case_Expression (N, Ctx_Type);
2836 when N_Character_Literal
2837 => Resolve_Character_Literal (N, Ctx_Type);
2839 when N_Expanded_Name
2840 => Resolve_Entity_Name (N, Ctx_Type);
2842 when N_Explicit_Dereference
2843 => Resolve_Explicit_Dereference (N, Ctx_Type);
2845 when N_Expression_With_Actions
2846 => Resolve_Expression_With_Actions (N, Ctx_Type);
2848 when N_Extension_Aggregate
2849 => Resolve_Extension_Aggregate (N, Ctx_Type);
2851 when N_Function_Call
2852 => Resolve_Call (N, Ctx_Type);
2854 when N_Identifier
2855 => Resolve_Entity_Name (N, Ctx_Type);
2857 when N_If_Expression
2858 => Resolve_If_Expression (N, Ctx_Type);
2860 when N_Indexed_Component
2861 => Resolve_Indexed_Component (N, Ctx_Type);
2863 when N_Integer_Literal
2864 => Resolve_Integer_Literal (N, Ctx_Type);
2866 when N_Membership_Test
2867 => Resolve_Membership_Op (N, Ctx_Type);
2869 when N_Null => Resolve_Null (N, Ctx_Type);
2871 when N_Op_And | N_Op_Or | N_Op_Xor
2872 => Resolve_Logical_Op (N, Ctx_Type);
2874 when N_Op_Eq | N_Op_Ne
2875 => Resolve_Equality_Op (N, Ctx_Type);
2877 when N_Op_Lt | N_Op_Le | N_Op_Gt | N_Op_Ge
2878 => Resolve_Comparison_Op (N, Ctx_Type);
2880 when N_Op_Not => Resolve_Op_Not (N, Ctx_Type);
2882 when N_Op_Add | N_Op_Subtract | N_Op_Multiply |
2883 N_Op_Divide | N_Op_Mod | N_Op_Rem
2885 => Resolve_Arithmetic_Op (N, Ctx_Type);
2887 when N_Op_Concat => Resolve_Op_Concat (N, Ctx_Type);
2889 when N_Op_Expon => Resolve_Op_Expon (N, Ctx_Type);
2891 when N_Op_Plus | N_Op_Minus | N_Op_Abs
2892 => Resolve_Unary_Op (N, Ctx_Type);
2894 when N_Op_Shift => Resolve_Shift (N, Ctx_Type);
2896 when N_Procedure_Call_Statement
2897 => Resolve_Call (N, Ctx_Type);
2899 when N_Operator_Symbol
2900 => Resolve_Operator_Symbol (N, Ctx_Type);
2902 when N_Qualified_Expression
2903 => Resolve_Qualified_Expression (N, Ctx_Type);
2905 -- Why is the following null, needs a comment ???
2907 when N_Quantified_Expression
2908 => null;
2910 when N_Raise_Expression
2911 => Resolve_Raise_Expression (N, Ctx_Type);
2913 when N_Raise_xxx_Error
2914 => Set_Etype (N, Ctx_Type);
2916 when N_Range => Resolve_Range (N, Ctx_Type);
2918 when N_Real_Literal
2919 => Resolve_Real_Literal (N, Ctx_Type);
2921 when N_Reference => Resolve_Reference (N, Ctx_Type);
2923 when N_Selected_Component
2924 => Resolve_Selected_Component (N, Ctx_Type);
2926 when N_Slice => Resolve_Slice (N, Ctx_Type);
2928 when N_String_Literal
2929 => Resolve_String_Literal (N, Ctx_Type);
2931 when N_Type_Conversion
2932 => Resolve_Type_Conversion (N, Ctx_Type);
2934 when N_Unchecked_Expression =>
2935 Resolve_Unchecked_Expression (N, Ctx_Type);
2937 when N_Unchecked_Type_Conversion =>
2938 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
2939 end case;
2941 -- Ada 2012 (AI05-0149): Apply an (implicit) conversion to an
2942 -- expression of an anonymous access type that occurs in the context
2943 -- of a named general access type, except when the expression is that
2944 -- of a membership test. This ensures proper legality checking in
2945 -- terms of allowed conversions (expressions that would be illegal to
2946 -- convert implicitly are allowed in membership tests).
2948 if Ada_Version >= Ada_2012
2949 and then Ekind (Ctx_Type) = E_General_Access_Type
2950 and then Ekind (Etype (N)) = E_Anonymous_Access_Type
2951 and then Nkind (Parent (N)) not in N_Membership_Test
2952 then
2953 Rewrite (N, Convert_To (Ctx_Type, Relocate_Node (N)));
2954 Analyze_And_Resolve (N, Ctx_Type);
2955 end if;
2957 -- If the subexpression was replaced by a non-subexpression, then
2958 -- all we do is to expand it. The only legitimate case we know of
2959 -- is converting procedure call statement to entry call statements,
2960 -- but there may be others, so we are making this test general.
2962 if Nkind (N) not in N_Subexpr then
2963 Debug_A_Exit ("resolving ", N, " (done)");
2964 Expand (N);
2965 return;
2966 end if;
2968 -- The expression is definitely NOT overloaded at this point, so
2969 -- we reset the Is_Overloaded flag to avoid any confusion when
2970 -- reanalyzing the node.
2972 Set_Is_Overloaded (N, False);
2974 -- Freeze expression type, entity if it is a name, and designated
2975 -- type if it is an allocator (RM 13.14(10,11,13)).
2977 -- Now that the resolution of the type of the node is complete, and
2978 -- we did not detect an error, we can expand this node. We skip the
2979 -- expand call if we are in a default expression, see section
2980 -- "Handling of Default Expressions" in Sem spec.
2982 Debug_A_Exit ("resolving ", N, " (done)");
2984 -- We unconditionally freeze the expression, even if we are in
2985 -- default expression mode (the Freeze_Expression routine tests this
2986 -- flag and only freezes static types if it is set).
2988 -- Ada 2012 (AI05-177): The declaration of an expression function
2989 -- does not cause freezing, but we never reach here in that case.
2990 -- Here we are resolving the corresponding expanded body, so we do
2991 -- need to perform normal freezing.
2993 Freeze_Expression (N);
2995 -- Now we can do the expansion
2997 Expand (N);
2998 end if;
2999 end Resolve;
3001 -------------
3002 -- Resolve --
3003 -------------
3005 -- Version with check(s) suppressed
3007 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
3008 begin
3009 if Suppress = All_Checks then
3010 declare
3011 Sva : constant Suppress_Array := Scope_Suppress.Suppress;
3012 begin
3013 Scope_Suppress.Suppress := (others => True);
3014 Resolve (N, Typ);
3015 Scope_Suppress.Suppress := Sva;
3016 end;
3018 else
3019 declare
3020 Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
3021 begin
3022 Scope_Suppress.Suppress (Suppress) := True;
3023 Resolve (N, Typ);
3024 Scope_Suppress.Suppress (Suppress) := Svg;
3025 end;
3026 end if;
3027 end Resolve;
3029 -------------
3030 -- Resolve --
3031 -------------
3033 -- Version with implicit type
3035 procedure Resolve (N : Node_Id) is
3036 begin
3037 Resolve (N, Etype (N));
3038 end Resolve;
3040 ---------------------
3041 -- Resolve_Actuals --
3042 ---------------------
3044 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
3045 Loc : constant Source_Ptr := Sloc (N);
3046 A : Node_Id;
3047 A_Id : Entity_Id;
3048 A_Typ : Entity_Id;
3049 F : Entity_Id;
3050 F_Typ : Entity_Id;
3051 Prev : Node_Id := Empty;
3052 Orig_A : Node_Id;
3053 Real_F : Entity_Id;
3055 Real_Subp : Entity_Id;
3056 -- If the subprogram being called is an inherited operation for
3057 -- a formal derived type in an instance, Real_Subp is the subprogram
3058 -- that will be called. It may have different formal names than the
3059 -- operation of the formal in the generic, so after actual is resolved
3060 -- the name of the actual in a named association must carry the name
3061 -- of the actual of the subprogram being called.
3063 procedure Check_Aliased_Parameter;
3064 -- Check rules on aliased parameters and related accessibility rules
3065 -- in (RM 3.10.2 (10.2-10.4)).
3067 procedure Check_Argument_Order;
3068 -- Performs a check for the case where the actuals are all simple
3069 -- identifiers that correspond to the formal names, but in the wrong
3070 -- order, which is considered suspicious and cause for a warning.
3072 procedure Check_Prefixed_Call;
3073 -- If the original node is an overloaded call in prefix notation,
3075 -- Try_Object_Operation has already verified that there is a valid
3076 -- interpretation, but the form of the actual can only be determined
3077 -- once the primitive operation is identified.
3080 -- If the actual is missing in a call, insert in the actuals list
3081 -- an instance of the default expression. The insertion is always
3082 -- a named association.
3084 procedure Property_Error
3088 -- Emit an error concerning variable Var with entity Var_Id that has
3089 -- enabled property Prop_Nam when it acts as an actual parameter in a
3090 -- call and the corresponding formal parameter is of mode IN.
3093 -- Check whether T1 and T2, or their full views, are derived from a
3094 -- common type. Used to enforce the restrictions on array conversions
3095 -- of AI95-00246.
3098 -- Predicate to determine whether an actual that is a concatenation
3099 -- will be evaluated statically and does not need a transient scope.
3100 -- This must be determined before the actual is resolved and expanded
3101 -- because if needed the transient scope must be introduced earlier.
3103 -----------------------------
3104 -- Check_Aliased_Parameter --
3105 -----------------------------
3110 begin
3118 else
3125 -- In a generic body assume the worst for generic formals:
3126 -- they can have a constrained partial view (AI05-041).
3132 then
3135 else
3140 else
3152 then
3160 then
3161 Error_Msg_N
3167 --------------------------
3168 -- Check_Argument_Order --
3169 --------------------------
3172 begin
3173 -- Nothing to do if no parameters, or original node is neither a
3174 -- function call nor a procedure call statement (happens in the
3175 -- operator-transformed-to-function call case), or the call does
3176 -- not come from source, or this warning is off.
3178 if not Warn_On_Parameter_Order
3182 then
3186 declare
3189 begin
3190 -- Nothing to do if only one parameter
3196 -- Here if at least two arguments
3198 declare
3204 -- Set True if an out of order case is found
3206 begin
3207 -- Collect identifier names of actuals, fail if any actual is
3208 -- not a simple identifier, and record max length of name.
3214 else
3220 -- If we got this far, all actuals are identifiers and the list
3221 -- of their names is stored in the Actuals array.
3226 -- If we ran out of formals, that's odd, probably an error
3227 -- which will be detected elsewhere, but abandon the search.
3233 -- If name matches and is in order OK
3238 else
3239 -- If no match, see if it is elsewhere in list and if so
3240 -- flag potential wrong order if type is compatible.
3244 and then
3246 then
3252 -- No match
3260 -- If Formals left over, also probably an error, skip warning
3266 -- Here we give the warning if something was out of order
3269 Error_Msg_N
3276 -------------------------
3277 -- Check_Prefixed_Call --
3278 -------------------------
3287 begin
3288 -- Check whether the call is a prefixed call, with or without
3289 -- additional actuals.
3292 or else
3298 then
3301 then
3302 -- Introduce dereference on object in prefix
3304 New_A :=
3312 then
3313 -- Introduce an implicit 'Access in prefix
3316 Error_Msg_NE
3332 --------------------
3333 -- Insert_Default --
3334 --------------------
3340 begin
3341 -- Missing argument in call, nothing to insert
3346 else
3347 -- Note that we do a full New_Copy_Tree, so that any associated
3348 -- Itypes are properly copied. This may not be needed any more,
3349 -- but it does no harm as a safety measure. Defaults of a generic
3350 -- formal may be out of bounds of the corresponding actual (see
3351 -- cc1311b) and an additional check may be required.
3353 Actval :=
3354 New_Copy_Tree
3361 then
3367 then
3370 then
3371 -- If default is a real literal, do not introduce a
3372 -- conversion whose effect may depend on the run-time
3373 -- size of universal real.
3377 else
3388 -- Resolve aggregates with their base type, to avoid scope
3389 -- anomalies: the subtype was first built in the subprogram
3390 -- declaration, and the current call may be nested.
3394 else
3398 else
3401 -- See note above concerning aggregates
3405 then
3408 -- Resolve entities with their own type, which may differ from
3409 -- the type of a reference in a generic context (the view
3410 -- swapping mechanism did not anticipate the re-analysis of
3411 -- default values in calls).
3416 else
3421 -- If default is a tag indeterminate function call, propagate tag
3422 -- to obtain proper dispatching.
3426 then
3432 -- If the default expression raises constraint error, then just
3433 -- silently replace it with an N_Raise_Constraint_Error node, since
3434 -- we already gave the warning on the subprogram spec. If node is
3435 -- already a Raise_Constraint_Error leave as is, to prevent loops in
3436 -- the warnings removal machinery.
3440 then
3448 Assoc :=
3453 -- Case of insertion is first named actual
3457 then
3464 else
3468 else
3472 -- Case of insertion is not first named actual
3474 else
3475 Set_Next_Named_Actual
3487 --------------------
3488 -- Property_Error --
3489 --------------------
3491 procedure Property_Error
3495 is
3496 begin
3498 Error_Msg_NE
3504 -------------------
3505 -- Same_Ancestor --
3506 -------------------
3512 begin
3515 then
3521 then
3528 --------------------------
3529 -- Static_Concatenation --
3530 --------------------------
3533 begin
3540 -- Concatenation is static when both operands are static and
3541 -- the concatenation operator is a predefined one.
3544 and then
3546 and then
3551 declare
3553 begin
3556 and then
3560 else
3566 -- Start of processing for Resolve_Actuals
3568 begin
3569 Check_Argument_Order;
3573 and then In_Instance
3576 then
3578 else
3583 Check_Prefixed_Call;
3597 -- If we have an error in any actual or formal, indicated by a type
3598 -- of Any_Type, then abandon resolution attempt, and set result type
3599 -- to Any_Type. Skip this if the actual is a Raise_Expression, whose
3600 -- type is imposed from context.
3604 then
3611 -- Case where actual is present
3613 -- If the actual is an entity, generate a reference to it now. We
3614 -- do this before the actual is resolved, because a formal of some
3615 -- protected subprogram, or a task discriminant, will be rewritten
3616 -- during expansion, and the source entity reference may be lost.
3621 then
3627 then
3634 -- RM 6.4.1(12): For an out parameter that is passed by
3635 -- copy, the formal parameter object is created, and:
3637 -- * For an access type, the formal parameter is initialized
3638 -- from the value of the actual, without checking that the
3639 -- value satisfies any constraint, any predicate, or any
3640 -- exclusion of the null value.
3642 -- * For a scalar type that has the Default_Value aspect
3643 -- specified, the formal parameter is initialized from the
3644 -- value of the actual, without checking that the value
3645 -- satisfies any constraint or any predicate.
3646 -- I do not understand why this case is included??? this is
3647 -- not a case where an OUT parameter is treated as IN OUT.
3649 -- * For a composite type with discriminants or that has
3650 -- implicit initial values for any subcomponents, the
3651 -- behavior is as for an in out parameter passed by copy.
3653 -- Hence for these cases we generate the read reference now
3654 -- (the write reference will be generated later by
3655 -- Note_Possible_Modification).
3658 and then
3660 or else
3662 and then
3664 or else
3667 or else Is_Partially_Initialized_Type
3669 then
3679 then
3680 -- If style checking mode on, check match of formal name
3688 -- If the formal is Out or In_Out, do not resolve and expand the
3689 -- conversion, because it is subsequently expanded into explicit
3690 -- temporaries and assignments. However, the object of the
3691 -- conversion can be resolved. An exception is the case of tagged
3692 -- type conversion with a class-wide actual. In that case we want
3693 -- the tag check to occur and no temporary will be needed (no
3694 -- representation change can occur) and the parameter is passed by
3695 -- reference, so we go ahead and resolve the type conversion.
3696 -- Another exception is the case of reference to component or
3697 -- subcomponent of a bit-packed array, in which case we want to
3698 -- defer expansion to the point the in and out assignments are
3699 -- performed.
3704 then
3707 then
3708 -- In a view conversion, the conversion must be legal in
3709 -- both directions, and thus both component types must be
3710 -- aliased, or neither (4.6 (8)).
3712 -- The extra rule in 4.6 (24.9.2) seems unduly restrictive:
3713 -- the privacy requirement should not apply to generic
3714 -- types, and should be checked in an instance. ARG query
3715 -- is in order ???
3719 then
3720 Error_Msg_N
3724 -- Comment here??? what set of cases???
3726 elsif
3728 then
3729 -- Check view conv between unrelated by ref array types
3733 then
3734 Error_Msg_N
3738 -- In Ada 2005 mode, check view conversion component
3739 -- type cannot be private, tagged, or volatile. Note
3740 -- that we only apply this to source conversions. The
3741 -- generated code can contain conversions which are
3742 -- not subject to this test, and we cannot extract the
3743 -- component type in such cases since it is not present.
3747 then
3748 declare
3750 Component_Type
3752 begin
3757 then
3758 Error_Msg_N
3769 -- Resolve expression if conversion is all OK
3774 then
3778 -- If the actual is a function call that returns a limited
3779 -- unconstrained object that needs finalization, create a
3780 -- transient scope for it, so that it can receive the proper
3781 -- finalization list.
3786 and then Expander_Active
3788 then
3792 -- A small optimization: if one of the actuals is a concatenation
3793 -- create a block around a procedure call to recover stack space.
3794 -- This alleviates stack usage when several procedure calls in
3795 -- the same statement list use concatenation. We do not perform
3796 -- this wrapping for code statements, where the argument is a
3797 -- static string, and we want to preserve warnings involving
3798 -- sequences of such statements.
3802 and then Expander_Active
3803 and then
3807 then
3811 else
3815 and then
3818 then
3819 Error_Msg_N
3832 -- (Ada 2005: AI-251): If the actual is an allocator whose
3833 -- directly designated type is a class-wide interface, we build
3834 -- an anonymous access type to use it as the type of the
3835 -- allocator. Later, when the subprogram call is expanded, if
3836 -- the interface has a secondary dispatch table the expander
3837 -- will add a type conversion to force the correct displacement
3838 -- of the pointer.
3841 declare
3847 begin
3850 then
3853 Set_Directly_Designated_Type
3858 -- Ada 2005, AI-162:If the actual is an allocator, the
3859 -- innermost enclosing statement is the master of the
3860 -- created object. This needs to be done with expansion
3861 -- enabled only, otherwise the transient scope will not
3862 -- be removed in the expansion of the wrapped construct.
3865 and then Expander_Active
3866 then
3876 -- (Ada 2005): The call may be to a primitive operation of a
3877 -- tagged synchronized type, declared outside of the type. In
3878 -- this case the controlling actual must be converted to its
3879 -- corresponding record type, which is the formal type. The
3880 -- actual may be a subtype, either because of a constraint or
3881 -- because it is a generic actual, so use base type to locate
3882 -- concurrent type.
3889 then
3890 -- If the actual is overloaded, look for an interpretation
3891 -- that has a synchronized type.
3896 else
3897 declare
3901 begin
3906 then
3916 declare
3919 begin
3922 else
3926 -- Tagged synchronized type (case 1): the actual is a
3927 -- concurrent type.
3931 then
3933 Unchecked_Convert_To
3937 -- Tagged synchronized type (case 2): the formal is a
3938 -- concurrent type.
3941 and then Present
3946 then
3949 -- Common case
3951 else
3956 -- Not a synchronized operation
3958 else
3966 -- An actual cannot be an untagged formal incomplete type
3971 then
3972 Error_Msg_N
3978 N_Procedure_Call_Statement)
3979 then
3980 -- In formal mode, check that actual parameters matching
3981 -- formals of tagged types are objects (or ancestor type
3982 -- conversions of objects), not general expressions.
3989 declare
3994 begin
3996 Check_SPARK_05_Restriction
3999 -- In formal mode, the only view conversions are those
4000 -- involving ancestor conversion of an extended type.
4002 elsif not
4008 then
4009 if Ekind_In
4011 then
4012 Check_SPARK_05_Restriction
4015 else
4016 Check_SPARK_05_Restriction
4020 else
4025 else
4029 -- In formal mode, the only view conversions are those
4030 -- involving ancestor conversion of an extended type.
4034 then
4035 Check_SPARK_05_Restriction
4041 -- has warnings suppressed, then we reset Never_Set_In_Source for
4042 -- the calling entity. The reason for this is to catch cases like
4043 -- GNAT.Spitbol.Patterns.Vstring_Var where the called subprogram
4044 -- uses trickery to modify an IN parameter.
4051 then
4055 -- Perform error checks for IN and IN OUT parameters
4059 -- Check unset reference. For scalar parameters, it is clearly
4060 -- wrong to pass an uninitialized value as either an IN or
4061 -- IN-OUT parameter. For composites, it is also clearly an
4062 -- error to pass a completely uninitialized value as an IN
4063 -- parameter, but the case of IN OUT is trickier. We prefer
4064 -- not to give a warning here. For example, suppose there is
4065 -- a routine that sets some component of a record to False.
4066 -- It is perfectly reasonable to make this IN-OUT and allow
4067 -- either initialized or uninitialized records to be passed
4068 -- in this case.
4070 -- For partially initialized composite values, we also avoid
4071 -- warnings, since it is quite likely that we are passing a
4072 -- partially initialized value and only the initialized fields
4073 -- will in fact be read in the subprogram.
4078 then
4082 -- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
4083 -- actual to a nested call, since this constitutes a reading of
4084 -- the parameter, which is not allowed.
4088 then
4090 Error_Msg_N
4093 -- An effectively volatile OUT parameter cannot act as IN or
4094 -- IN OUT actual in a call (SPARK RM 7.1.3(11)).
4098 then
4099 Error_Msg_N
4105 -- Case of OUT or IN OUT parameter
4109 -- For an Out parameter, check for useless assignment. Note
4110 -- that we can't set Last_Assignment this early, because we may
4111 -- kill current values in Resolve_Call, and that call would
4112 -- clobber the Last_Assignment field.
4114 -- Note: call Warn_On_Useless_Assignment before doing the check
4115 -- below for Is_OK_Variable_For_Out_Formal so that the setting
4116 -- of Referenced_As_LHS/Referenced_As_Out_Formal properly
4117 -- reflects the last assignment, not this one.
4124 then
4129 -- Validate the form of the actual. Note that the call to
4130 -- Is_OK_Variable_For_Out_Formal generates the required
4131 -- reference in this case.
4133 -- A call to an initialization procedure for an aggregate
4134 -- component may initialize a nested component of a constant
4135 -- designated object. In this context the object is variable.
4139 then
4143 and then
4146 then
4147 Error_Msg_N
4153 -- What's the following about???
4157 else
4158 Kill_All_Checks;
4167 -- Apply appropriate constraint/predicate checks for IN [OUT] case
4171 -- Apply predicate tests except in certain special cases. Note
4172 -- that it might be more consistent to apply these only when
4173 -- expansion is active (in Exp_Ch6.Expand_Actuals), as we do
4174 -- for the outbound predicate tests ???
4180 -- Apply required constraint checks
4182 -- Gigi looks at the check flag and uses the appropriate types.
4183 -- For now since one flag is used there is an optimization
4184 -- which might not be done in the IN OUT case since Gigi does
4185 -- not do any analysis. More thought required about this ???
4187 -- In fact is this comment obsolete??? doesn't the expander now
4188 -- generate all these tests anyway???
4201 then
4204 -- For view conversions of a discriminated object, apply
4205 -- check to object itself, the conversion alreay has the
4206 -- proper type.
4210 then
4217 then
4223 then
4226 else
4230 -- Ada 2005 (AI-231): Note that the controlling parameter case
4231 -- already existed in Ada 95, which is partially checked
4232 -- elsewhere (see Checks), and we don't want the warning
4233 -- message to differ.
4238 then
4240 Apply_Compile_Time_Constraint_Error
4246 Apply_Compile_Time_Constraint_Error
4255 -- Checks for OUT parameters and IN OUT parameters
4259 -- If there is a type conversion, to make sure the return value
4260 -- meets the constraints of the variable before the conversion.
4264 Apply_Scalar_Range_Check
4266 else
4267 Apply_Range_Check
4271 -- If no conversion apply scalar range checks and length checks
4272 -- base on the subtype of the actual (NOT that of the formal).
4274 else
4279 then
4281 else
4286 -- Note: we do not apply the predicate checks for the case of
4287 -- OUT and IN OUT parameters. They are instead applied in the
4288 -- Expand_Actuals routine in Exp_Ch6.
4291 -- An actual associated with an access parameter is implicitly
4292 -- converted to the anonymous access type of the formal and must
4293 -- satisfy the legality checks for access conversions.
4297 Error_Msg_N
4301 -- If the actual is an access selected component of a variable,
4302 -- the call may modify its designated object. It is reasonable
4303 -- to treat this as a potential modification of the enclosing
4304 -- record, to prevent spurious warnings that it should be
4305 -- declared as a constant, because intuitively programmers
4306 -- regard the designated subcomponent as part of the record.
4311 then
4316 -- Check bad case of atomic/volatile argument (RM C.6(12))
4320 then
4323 then
4324 Error_Msg_NE
4330 then
4331 Error_Msg_NE
4337 -- Check that subprograms don't have improper controlling
4338 -- arguments (RM 3.9.2 (9)).
4340 -- A primitive operation may have an access parameter of an
4341 -- incomplete tagged type, but a dispatching call is illegal
4342 -- if the type is still incomplete.
4348 declare
4350 begin
4354 then
4355 Error_Msg_NE
4366 -- Apply legality rule 3.9.2 (9/1)
4371 and then not In_Instance
4372 then
4377 Error_Msg_NE
4381 -- Apply the checks described in 3.10.2(27): if the context is a
4382 -- specific access-to-object, the actual cannot be class-wide.
4383 -- Use base type to exclude access_to_subprogram cases.
4390 and then
4395 -- Disable these checks for call to imported C++ subprograms
4397 and then not
4401 then
4402 Error_Msg_N
4407 Error_Msg_NE
4412 Check_Aliased_Parameter;
4416 -- If it is a named association, treat the selector_name as a
4417 -- proper identifier, and mark the corresponding entity.
4421 -- Ignore reference in SPARK mode, as it refers to an entity not
4422 -- in scope at the point of reference, so the reference should
4423 -- be ignored for computing effects of subprograms.
4425 and then not GNATprove_Mode
4426 then
4427 -- If subprogram is overridden, use name of formal that
4428 -- is being called.
4434 else
4448 -- The following checks are only relevant when SPARK_Mode is on as
4449 -- they are not standard Ada legality rule. Internally generated
4450 -- temporaries are ignored.
4455 then
4456 -- An effectively volatile object may act as an actual
4457 -- parameter when the corresponding formal is of a non-scalar
4458 -- volatile type.
4462 then
4465 -- An effectively volatile object may act as an actual
4466 -- parameter in a call to an instance of Unchecked_Conversion.
4471 else
4472 Error_Msg_N
4477 -- Detect an external variable with an enabled property that
4478 -- does not match the mode of the corresponding formal in a
4479 -- procedure call. Functions are not considered because they
4480 -- cannot have effectively volatile formal parameters in the
4481 -- first place.
4488 then
4501 -- A formal parameter of a specific tagged type whose related
4502 -- subprogram is subject to pragma Extensions_Visible with value
4503 -- "False" cannot act as an actual in a subprogram with value
4504 -- "True" (SPARK RM 6.1.7(3)).
4508 Extensions_Visible_True
4509 then
4510 Error_Msg_N
4513 Error_Msg_NE
4517 -- The actual parameter of a Ghost subprogram whose formal is of
4518 -- mode IN OUT or OUT must be a Ghost variable (SPARK RM 6.9(13)).
4525 then
4526 Error_Msg_NE
4532 else
4539 -- Case where actual is not present
4541 else
4542 Insert_Default;
4553 -----------------------
4554 -- Resolve_Allocator --
4555 -----------------------
4567 procedure Check_Allocator_Discrim_Accessibility
4570 -- Check that accessibility level associated with an access discriminant
4571 -- initialized in an allocator by the expression Disc_Exp is not deeper
4572 -- than the level of the allocator type Alloc_Typ. An error message is
4573 -- issued if this condition is violated. Specialized checks are done for
4574 -- the cases of a constraint expression which is an access attribute or
4575 -- an access discriminant.
4578 -- If the allocator is an actual in a call, it is allowed to be class-
4579 -- wide when the context is not because it is a controlling actual.
4581 -------------------------------------------
4582 -- Check_Allocator_Discrim_Accessibility --
4583 -------------------------------------------
4585 procedure Check_Allocator_Discrim_Accessibility
4588 is
4589 begin
4592 then
4593 Error_Msg_N
4596 -- When the expression is an Access attribute the level of the prefix
4597 -- object must not be deeper than that of the allocator's type.
4601 Attribute_Access
4604 then
4605 Error_Msg_N
4607 Disc_Exp);
4609 -- When the expression is an access discriminant the check is against
4610 -- the level of the prefix object.
4616 then
4617 Error_Msg_N
4619 Disc_Exp);
4621 -- All other cases are legal
4623 else
4628 ----------------------------
4629 -- In_Dispatching_Context --
4630 ----------------------------
4635 begin
4641 -- Start of processing for Resolve_Allocator
4643 begin
4644 -- Replace general access with specific type
4654 -- For qualified expression, resolve the expression using the given
4655 -- subtype (nothing to do for type mark, subtype indication)
4660 and then not In_Dispatching_Context
4661 then
4662 Error_Msg_N
4670 -- A qualified expression requires an exact match of the type.
4671 -- Class-wide matching is not allowed.
4676 then
4680 -- Calls to build-in-place functions are not currently supported in
4681 -- allocators for access types associated with a simple storage pool.
4682 -- Supporting such allocators may require passing additional implicit
4683 -- parameters to build-in-place functions (or a significant revision
4684 -- of the current b-i-p implementation to unify the handling for
4685 -- multiple kinds of storage pools). ???
4689 then
4690 declare
4693 begin
4695 and then
4696 Present (Get_Rep_Pragma
4698 then
4699 Error_Msg_N
4706 -- A special accessibility check is needed for allocators that
4707 -- constrain access discriminants. The level of the type of the
4708 -- expression used to constrain an access discriminant cannot be
4709 -- deeper than the type of the allocator (in contrast to access
4710 -- parameters, where the level of the actual can be arbitrary).
4712 -- We can't use Valid_Conversion to perform this check because in
4713 -- general the type of the allocator is unrelated to the type of
4714 -- the access discriminant.
4718 then
4725 then
4728 -- Get the first component expression of the aggregate
4738 else
4742 else
4761 else
4766 else
4775 -- For a subtype mark or subtype indication, freeze the subtype
4777 else
4781 Error_Msg_N
4785 -- A special accessibility check is needed for allocators that
4786 -- constrain access discriminants. The level of the type of the
4787 -- expression used to constrain an access discriminant cannot be
4788 -- deeper than the type of the allocator (in contrast to access
4789 -- parameters, where the level of the actual can be arbitrary).
4790 -- We can't use Valid_Conversion to perform this check because
4791 -- in general the type of the allocator is unrelated to the type
4792 -- of the access discriminant.
4797 then
4807 else
4821 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
4822 -- check that the level of the type of the created object is not deeper
4823 -- than the level of the allocator's access type, since extensions can
4824 -- now occur at deeper levels than their ancestor types. This is a
4825 -- static accessibility level check; a run-time check is also needed in
4826 -- the case of an initialized allocator with a class-wide argument (see
4827 -- Expand_Allocator_Expression).
4831 then
4832 declare
4835 begin
4840 else
4846 then
4849 Error_Msg_N
4858 -- Do not apply Ada 2005 accessibility checks on a class-wide
4859 -- allocator if the type given in the allocator is a formal
4860 -- type. A run-time check will be performed in the instance.
4870 -- Check for allocation from an empty storage pool
4875 -- If the context is an unchecked conversion, as may happen within an
4876 -- inlined subprogram, the allocator is being resolved with its own
4877 -- anonymous type. In that case, if the target type has a specific
4878 -- storage pool, it must be inherited explicitly by the allocator type.
4882 then
4883 Set_Associated_Storage_Pool
4891 -- Check that an allocator with task parts isn't for a nested access
4892 -- type when restriction No_Task_Hierarchy applies.
4896 then
4900 -- An illegal allocator may be rewritten as a raise Program_Error
4901 -- statement.
4905 -- An anonymous access discriminant is the definition of a
4906 -- coextension.
4910 N_Discriminant_Specification
4911 then
4912 declare
4916 begin
4919 -- Ada 2012 AI05-0052: If the designated type of the allocator
4920 -- is limited, then the allocator shall not be used to define
4921 -- the value of an access discriminant unless the discriminated
4922 -- type is immutably limited.
4927 then
4928 Error_Msg_N
4934 -- Avoid marking an allocator as a dynamic coextension if it is
4935 -- within a static construct.
4941 -- Cleanup for potential static coextensions
4943 else
4949 -- Report a simple error: if the designated object is a local task,
4950 -- its body has not been seen yet, and its activation will fail an
4951 -- elaboration check.
4958 then
4964 -- Ada 2012 (AI05-0111-3): Detect an attempt to allocate a task or a
4965 -- type with a task component on a subpool. This action must raise
4966 -- Program_Error at runtime.
4972 then
4984 ---------------------------
4985 -- Resolve_Arithmetic_Op --
4986 ---------------------------
4988 -- Used for resolving all arithmetic operators except exponentiation
4999 -- We do the resolution using the base type, because intermediate values
5000 -- in expressions always are of the base type, not a subtype of it.
5003 -- Returns True if N is in a context that expects "any real type"
5006 -- Return True iff given type is Integer or universal real/integer
5009 -- Choose type of integer literal in fixed-point operation to conform
5010 -- to available fixed-point type. T is the type of the other operand,
5011 -- which is needed to determine the expected type of N.
5014 -- Set operand type to T if universal
5016 -------------------------------
5017 -- Expected_Type_Is_Any_Real --
5018 -------------------------------
5021 begin
5022 -- N is the expression after "delta" in a fixed_point_definition;
5023 -- see RM-3.5.9(6):
5026 N_Decimal_Fixed_Point_Definition,
5028 -- N is one of the bounds in a real_range_specification;
5029 -- see RM-3.5.7(5):
5031 N_Real_Range_Specification,
5033 -- N is the expression of a delta_constraint;
5034 -- see RM-J.3(3):
5036 N_Delta_Constraint);
5039 -----------------------------
5040 -- Is_Integer_Or_Universal --
5041 -----------------------------
5048 begin
5054 else
5060 then
5071 ----------------------------
5072 -- Set_Mixed_Mode_Operand --
5073 ----------------------------
5079 begin
5082 -- A universal integer literal is resolved as standard integer
5083 -- except in the case of a fixed-point result, where we leave it
5084 -- as universal (to be handled by Exp_Fixd later on)
5088 else
5096 then
5097 -- A universal real can appear in a fixed-type context. We resolve
5098 -- the literal with that context, even though this might raise an
5099 -- exception prematurely (the other operand may be zero).
5106 then
5107 -- Integer arg in mixed-mode operation. Resolve with universal
5108 -- type, in case preference rule must be applied.
5114 then
5115 -- Not a mixed-mode operation, resolve with context
5121 -- N may itself be a mixed-mode operation, so use context type
5128 then
5129 -- Must be (fixed * fixed) operation, operand must have one
5130 -- compatible interpretation.
5137 then
5138 -- C * F(X) in a fixed context, where C is a real literal or a
5139 -- fixed-point expression. F must have either a fixed type
5140 -- interpretation or an integer interpretation, but not both.
5147 else
5154 else
5162 -- Reanalyze the literal with the fixed type of the context. If
5163 -- context is Universal_Fixed, we are within a conversion, leave
5164 -- the literal as a universal real because there is no usable
5165 -- fixed type, and the target of the conversion plays no role in
5166 -- the resolution.
5168 declare
5172 begin
5175 else
5181 then
5183 else
5191 else
5196 ----------------------
5197 -- Set_Operand_Type --
5198 ----------------------
5201 begin
5204 then
5209 -- Start of processing for Resolve_Arithmetic_Op
5211 begin
5216 then
5220 -- Special-case for mixed-mode universal expressions or fixed point type
5221 -- operation: each argument is resolved separately. The same treatment
5222 -- is required if one of the operands of a fixed point operation is
5223 -- universal real, since in this case we don't do a conversion to a
5224 -- specific fixed-point type (instead the expander handles the case).
5226 -- Set the type of the node to its universal interpretation because
5227 -- legality checks on an exponentiation operand need the context.
5232 then
5243 or else
5246 then
5251 -- If context is a fixed type and one operand is integer, the other
5252 -- is resolved with the type of the context.
5257 then
5264 then
5268 else
5273 -- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
5274 -- multiplying operators from being used when the expected type is
5275 -- also universal_fixed. Note that B_Typ will be Universal_Fixed in
5276 -- some cases where the expected type is actually Any_Real;
5277 -- Expected_Type_Is_Any_Real takes care of that case.
5281 then
5285 N_Unchecked_Type_Conversion)
5286 then
5293 else
5296 and then not
5298 N_Unchecked_Type_Conversion)
5299 then
5300 Error_Msg_N
5305 -- The expected type is "any real type" in contexts like
5307 -- type T is delta <universal_fixed-expression> ...
5309 -- in which case we need to set the type to Universal_Real
5310 -- so that static expression evaluation will work properly.
5314 else
5324 then
5329 -- If no previous errors, this is only possible if one operand is
5330 -- overloaded and the context is universal. Resolve as such.
5335 else
5337 and then
5339 then
5343 -- If the context is Universal_Fixed and the operands are also
5344 -- universal fixed, this is an error, unless there is only one
5345 -- applicable fixed_point type (usually Duration).
5353 else
5358 else
5363 -- If one of the arguments was resolved to a non-universal type.
5364 -- label the result of the operation itself with the same type.
5365 -- Do the same for the universal argument, if any.
5377 -- In SPARK, a multiplication or division with operands of fixed point
5378 -- types must be qualified or explicitly converted to identify the
5379 -- result type.
5384 and then
5386 then
5387 Check_SPARK_05_Restriction
5391 -- Set overflow and division checking bit
5398 -- Give warning if explicit division by zero
5402 then
5408 or else
5411 then
5412 -- Specialize the warning message according to the operation.
5413 -- The following warnings are for the case
5418 -- For division, we have two cases, for float division
5419 -- of an unconstrained float type, on a machine where
5420 -- Machine_Overflows is false, we don't get an exception
5421 -- at run-time, but rather an infinity or Nan. The Nan
5422 -- case is pretty obscure, so just warn about infinities.
5426 and then not Machine_Overflows_On_Target
5427 then
5428 Error_Msg_N
5432 -- For all other cases, we get a Constraint_Error
5434 else
5435 Apply_Compile_Time_Constraint_Error
5441 Apply_Compile_Time_Constraint_Error
5446 Apply_Compile_Time_Constraint_Error
5450 -- Division by zero can only happen with division, rem,
5451 -- and mod operations.
5457 -- Otherwise just set the flag to check at run time
5459 else
5464 -- If Restriction No_Implicit_Conditionals is active, then it is
5465 -- violated if either operand can be negative for mod, or for rem
5466 -- if both operands can be negative.
5470 then
5471 declare
5478 -- Set if corresponding operand might be negative
5480 begin
5481 Determine_Range
5485 Determine_Range
5489 -- Check if we will be generating conditionals. There are two
5490 -- cases where that can happen, first for REM, the only case
5491 -- is largest negative integer mod -1, where the division can
5492 -- overflow, but we still have to give the right result. The
5493 -- front end generates a test for this annoying case. Here we
5494 -- just test if both operands can be negative (that's what the
5495 -- expander does, so we match its logic here).
5497 -- The second case is mod where either operand can be negative.
5498 -- In this case, the back end has to generate additional tests.
5501 or else
5503 then
5514 ------------------
5515 -- Resolve_Call --
5516 ------------------
5519 function Same_Or_Aliased_Subprograms
5522 -- Returns True if the subprogram entity S is the same as E or else
5523 -- S is an alias of E.
5525 ---------------------------------
5526 -- Same_Or_Aliased_Subprograms --
5527 ---------------------------------
5529 function Same_Or_Aliased_Subprograms
5532 is
5534 begin
5538 -- Local variables
5552 -- Start of processing for Resolve_Call
5554 begin
5555 -- The context imposes a unique interpretation with type Typ on a
5556 -- procedure or function call. Find the entity of the subprogram that
5557 -- yields the expected type, and propagate the corresponding formal
5558 -- constraints on the actuals. The caller has established that an
5559 -- interpretation exists, and emitted an error if not unique.
5561 -- First deal with the case of a call to an access-to-subprogram,
5562 -- dereference made explicit in Analyze_Call.
5568 else
5569 -- Find the interpretation whose type (a subprogram type) has a
5570 -- return type that is compatible with the context. Analysis of
5571 -- the node has established that one exists.
5590 -- If the prefix is not an entity, then resolve it
5596 -- For an indirect call, we always invalidate checks, since we do not
5597 -- know whether the subprogram is local or global. Yes we could do
5598 -- better here, e.g. by knowing that there are no local subprograms,
5599 -- but it does not seem worth the effort. Similarly, we kill all
5600 -- knowledge of current constant values.
5602 Kill_Current_Values;
5604 -- If this is a procedure call which is really an entry call, do
5605 -- the conversion of the procedure call to an entry call. Protected
5606 -- operations use the same circuitry because the name in the call
5607 -- can be an arbitrary expression with special resolution rules.
5612 then
5616 -- Kill checks and constant values, as above for indirect case
5617 -- Who knows what happens when another task is activated?
5619 Kill_Current_Values;
5622 -- Normal subprogram call with name established in Resolve
5628 -- Otherwise we must have the case of an overloaded call
5630 else
5633 -- Initialize Nam to prevent warning (we know it will be assigned
5634 -- in the loop below, but the compiler does not know that).
5654 then
5655 -- The prefix is a parameterless function call that returns an access
5656 -- to subprogram. If parameters are present in the current call, add
5657 -- add an explicit dereference. We use the base type here because
5658 -- within an instance these may be subtypes.
5660 -- The dereference is added either in Analyze_Call or here. Should
5661 -- be consolidated ???
5670 -- Check that a call to Current_Task does not occur in an entry body
5673 declare
5676 begin
5678 loop
5681 -- Exclude calls that occur within the default of a formal
5682 -- parameter of the entry, since those are evaluated outside
5683 -- of the body.
5690 then
5693 Error_Msg_NE
5707 -- Check that a procedure call does not occur in the context of the
5708 -- entry call statement of a conditional or timed entry call. Note that
5709 -- the case of a call to a subprogram renaming of an entry will also be
5710 -- rejected. The test for N not being an N_Entry_Call_Statement is
5711 -- defensive, covering the possibility that the processing of entry
5712 -- calls might reach this point due to later modifications of the code
5713 -- above.
5718 then
5722 -- Ada 2005 (AI-345): If a procedure_call_statement is used
5723 -- for a procedure_or_entry_call, the procedure_name or
5724 -- procedure_prefix of the procedure_call_statement shall denote
5725 -- an entry renamed by a procedure, or (a view of) a primitive
5726 -- subprogram of a limited interface whose first parameter is
5727 -- a controlling parameter.
5732 then
5733 Error_Msg_N
5738 -- If the SPARK_05 restriction is active, we are not allowed
5739 -- to have a call to a subprogram before we see its completion.
5744 -- Don't flag strange internal calls
5749 -- Only flag calls in extended main source
5754 -- Exclude enumeration literals from this processing
5757 then
5758 Check_SPARK_05_Restriction
5762 -- Check that this is not a call to a protected procedure or entry from
5763 -- within a protected function.
5767 -- Freeze the subprogram name if not in a spec-expression. Note that
5768 -- we freeze procedure calls as well as function calls. Procedure calls
5769 -- are not frozen according to the rules (RM 13.14(14)) because it is
5770 -- impossible to have a procedure call to a non-frozen procedure in
5771 -- pure Ada, but in the code that we generate in the expander, this
5772 -- rule needs extending because we can generate procedure calls that
5773 -- need freezing.
5775 -- In Ada 2012, expression functions may be called within pre/post
5776 -- conditions of subsequent functions or expression functions. Such
5777 -- calls do not freeze when they appear within generated bodies,
5778 -- (including the body of another expression function) which would
5779 -- place the freeze node in the wrong scope. An expression function
5780 -- is frozen in the usual fashion, by the appearance of a real body,
5781 -- or at the end of a declarative part.
5785 and then
5788 then
5792 -- For a predefined operator, the type of the result is the type imposed
5793 -- by context, except for a predefined operation on universal fixed.
5794 -- Otherwise The type of the call is the type returned by the subprogram
5795 -- being called.
5802 -- If the subprogram returns an array type, and the context requires the
5803 -- component type of that array type, the node is really an indexing of
5804 -- the parameterless call. Resolve as such. A pathological case occurs
5805 -- when the type of the component is an access to the array type. In
5806 -- this case the call is truly ambiguous.
5809 and then
5812 or else
5815 and then
5817 then
5818 declare
5823 begin
5826 then
5827 Error_Msg_N
5829 else
5832 -- The called entity may be an explicit dereference, in which
5833 -- case there is no entity to set.
5841 or else
5843 and then
5845 then
5848 -- Indexed call to a parameterless function
5850 Index_Node :=
5852 Prefix =>
5855 else
5856 -- An Ada 2005 prefixed call to a primitive operation
5857 -- whose first parameter is the prefix. This prefix was
5858 -- prepended to the parameter list, which is actually a
5859 -- list of indexes. Remove the prefix in order to build
5860 -- the proper indexed component.
5862 Index_Node :=
5864 Prefix =>
5867 Parameter_Associations =>
5868 New_List
5873 -- Preserve the parenthesis count of the node
5877 -- Since we are correcting a node classification error made
5878 -- by the parser, we call Replace rather than Rewrite.
5892 else
5896 -- In the case where the call is to an overloaded subprogram, Analyze
5897 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
5898 -- such a case Normalize_Actuals needs to be called once more to order
5899 -- the actuals correctly. Otherwise the call will have the ordering
5900 -- given by the last overloaded subprogram whether this is the correct
5901 -- one being called or not.
5908 -- In any case, call is fully resolved now. Reset Overload flag, to
5909 -- prevent subsequent overload resolution if node is analyzed again
5914 -- A Ghost entity must appear in a specific context
5920 -- If we are calling the current subprogram from immediately within its
5921 -- body, then that is the case where we can sometimes detect cases of
5922 -- infinite recursion statically. Do not try this in case restriction
5923 -- No_Recursion is in effect anyway, and do it only for source calls.
5928 -- Check violation of SPARK_05 restriction which does not permit
5929 -- a subprogram body to contain a call to the subprogram directly.
5933 then
5934 Check_SPARK_05_Restriction
5938 -- Issue warning for possible infinite recursion in the absence
5939 -- of the No_Recursion restriction.
5944 then
5945 -- Here we detected and flagged an infinite recursion, so we do
5946 -- not need to test the case below for further warnings. Also we
5947 -- are all done if we now have a raise SE node.
5953 -- If call is to immediately containing subprogram, then check for
5954 -- the case of a possible run-time detectable infinite recursion.
5956 else
5960 -- Although in general case, recursion is not statically
5961 -- checkable, the case of calling an immediately containing
5962 -- subprogram is easy to catch.
5966 -- If the recursive call is to a parameterless subprogram,
5967 -- then even if we can't statically detect infinite
5968 -- recursion, this is pretty suspicious, and we output a
5969 -- warning. Furthermore, we will try later to detect some
5970 -- cases here at run time by expanding checking code (see
5971 -- Detect_Infinite_Recursion in package Exp_Ch6).
5973 -- If the recursive call is within a handler, do not emit a
5974 -- warning, because this is a common idiom: loop until input
5975 -- is correct, catch illegal input in handler and restart.
5981 then
5982 -- For the case of a procedure call. We give the message
5983 -- only if the call is the first statement in a sequence
5984 -- of statements, or if all previous statements are
5985 -- simple assignments. This is simply a heuristic to
5986 -- decrease false positives, without losing too many good
5987 -- warnings. The idea is that these previous statements
5988 -- may affect global variables the procedure depends on.
5989 -- We also exclude raise statements, that may arise from
5990 -- constraint checks and are probably unrelated to the
5991 -- intended control flow.
5995 then
5996 declare
5998 begin
6002 N_Raise_Constraint_Error)
6003 then
6012 -- Do not give warning if we are in a conditional context
6014 declare
6016 begin
6022 then
6027 -- Here warning is to be issued
6043 -- Check obsolescent reference to Ada.Characters.Handling subprogram
6047 -- If subprogram name is a predefined operator, it was given in
6048 -- functional notation. Replace call node with operator node, so
6049 -- that actuals can be resolved appropriately.
6057 then
6063 -- Create a transient scope if the resulting type requires it
6065 -- There are several notable exceptions:
6067 -- a) In init procs, the transient scope overhead is not needed, and is
6068 -- even incorrect when the call is a nested initialization call for a
6069 -- component whose expansion may generate adjust calls. However, if the
6070 -- call is some other procedure call within an initialization procedure
6071 -- (for example a call to Create_Task in the init_proc of the task
6072 -- run-time record) a transient scope must be created around this call.
6074 -- b) Enumeration literal pseudo-calls need no transient scope
6076 -- c) Intrinsic subprograms (Unchecked_Conversion and source info
6077 -- functions) do not use the secondary stack even though the return
6078 -- type may be unconstrained.
6080 -- d) Calls to a build-in-place function, since such functions may
6081 -- allocate their result directly in a target object, and cases where
6082 -- the result does get allocated in the secondary stack are checked for
6083 -- within the specialized Exp_Ch6 procedures for expanding those
6084 -- build-in-place calls.
6086 -- e) If the subprogram is marked Inline_Always, then even if it returns
6087 -- an unconstrained type the call does not require use of the secondary
6088 -- stack. However, inlining will only take place if the body to inline
6089 -- is already present. It may not be available if e.g. the subprogram is
6090 -- declared in a child instance.
6092 -- If this is an initialization call for a type whose construction
6093 -- uses the secondary stack, and it is not a nested call to initialize
6094 -- a component, we do need to create a transient scope for it. We
6095 -- check for this by traversing the type in Check_Initialization_Call.
6101 then
6107 then
6110 elsif Expander_Active
6113 and then
6115 or else
6117 then
6120 -- If the call appears within the bounds of a loop, it will
6121 -- be rewritten and reanalyzed, nothing left to do here.
6128 and then not Within_Init_Proc
6129 then
6133 -- A protected function cannot be called within the definition of the
6134 -- enclosing protected type, unless it is part of a pre/postcondition
6135 -- on another protected operation.
6140 and then not In_Spec_Expression
6141 then
6142 Error_Msg_NE
6146 -- Propagate interpretation to actuals, and add default expressions
6147 -- where needed.
6152 -- Overloaded literals are rewritten as function calls, for purpose of
6153 -- resolution. After resolution, we can replace the call with the
6154 -- literal itself.
6160 -- Avoid validation, since it is a static function call
6166 -- If the subprogram is not global, then kill all saved values and
6167 -- checks. This is a bit conservative, since in many cases we could do
6168 -- better, but it is not worth the effort. Similarly, we kill constant
6169 -- values. However we do not need to do this for internal entities
6170 -- (unless they are inherited user-defined subprograms), since they
6171 -- are not in the business of molesting local values.
6173 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
6174 -- kill all checks and values for calls to global subprograms. This
6175 -- takes care of the case where an access to a local subprogram is
6176 -- taken, and could be passed directly or indirectly and then called
6177 -- from almost any context.
6179 -- Note: we do not do this step till after resolving the actuals. That
6180 -- way we still take advantage of the current value information while
6181 -- scanning the actuals.
6183 -- We suppress killing values if we are processing the nodes associated
6184 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
6185 -- type kills all the values as part of analyzing the code that
6186 -- initializes the dispatch tables.
6190 or else Suppress_Value_Tracking_On_Call
6195 then
6196 Kill_Current_Values;
6199 -- If we are warning about unread OUT parameters, this is the place to
6200 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
6201 -- after the above call to Kill_Current_Values (since that call clears
6202 -- the Last_Assignment field of all local variables).
6207 then
6208 declare
6212 begin
6222 then
6232 -- If the subprogram is a primitive operation, check whether or not
6233 -- it is a correct dispatching call.
6237 then
6242 and then not In_Instance
6243 then
6247 -- If this is a dispatching call, generate the appropriate reference,
6248 -- for better source navigation in GPS.
6252 then
6255 -- Normal case, not a dispatching call: generate a call reference
6257 else
6265 -- Check for violation of restriction No_Specific_Termination_Handlers
6266 -- and warn on a potentially blocking call to Abort_Task.
6270 or else
6272 then
6279 -- A call to Ada.Real_Time.Timing_Events.Set_Handler to set a relative
6280 -- timing event violates restriction No_Relative_Delay (AI-0211). We
6281 -- need to check the second argument to determine whether it is an
6282 -- absolute or relative timing event.
6287 then
6291 -- Issue an error for a call to an eliminated subprogram. This routine
6292 -- will not perform the check if the call appears within a default
6293 -- expression.
6297 -- In formal mode, the primitive operations of a tagged type or type
6298 -- extension do not include functions that return the tagged type.
6304 then
6308 -- Implement rule in 12.5.1 (23.3/2): In an instance, if the actual is
6309 -- class-wide and the call dispatches on result in a context that does
6310 -- not provide a tag, the call raises Program_Error.
6313 and then In_Instance
6318 then
6319 -- Verify that none of the formals are controlling
6321 declare
6325 begin
6347 -- Check for calling a function with OUT or IN OUT parameter when the
6348 -- calling context (us right now) is not Ada 2012, so does not allow
6349 -- OUT or IN OUT parameters in function calls. Functions declared in
6350 -- a predefined unit are OK, as they may be called indirectly from a
6351 -- user-declared instantiation.
6357 then
6362 -- Check the dimensions of the actuals in the call. For function calls,
6363 -- propagate the dimensions from the returned type to N.
6367 -- All done, evaluate call and deal with elaboration issues
6372 -- In GNATprove mode, expansion is disabled, but we want to inline some
6373 -- subprograms to facilitate formal verification. Indirect calls through
6374 -- a subprogram type or within a generic cannot be inlined. Inlining is
6375 -- performed only for calls subject to SPARK_Mode on.
6377 if GNATprove_Mode
6380 and then not Inside_A_Generic
6381 then
6388 -- Nothing to do if the subprogram is not eligible for inlining in
6389 -- GNATprove mode.
6393 then
6396 -- Calls cannot be inlined inside assertions, as GNATprove treats
6397 -- assertions as logic expressions.
6404 -- Calls cannot be inlined inside default expressions
6411 -- Inlining should not be performed during pre-analysis
6415 -- With the one-pass inlining technique, a call cannot be
6416 -- inlined if the corresponding body has not been seen yet.
6419 Error_Msg_NE
6424 -- Nothing to do if there is no body to inline, indicating that
6425 -- the subprogram is not suitable for inlining in GNATprove
6426 -- mode.
6431 -- Calls cannot be inlined inside potentially unevaluated
6432 -- expressions, as this would create complex actions inside
6433 -- expressions, that are not handled by GNATprove.
6437 Error_Msg_N
6441 -- Otherwise, inline the call
6443 else
6453 -----------------------------
6454 -- Resolve_Case_Expression --
6455 -----------------------------
6461 begin
6468 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
6469 -- dynamically tagged must be known statically.
6489 -------------------------------
6490 -- Resolve_Character_Literal --
6491 -------------------------------
6497 begin
6498 -- Verify that the character does belong to the type of the context
6503 -- Wide_Wide_Character literals must always be defined, since the set
6504 -- of wide wide character literals is complete, i.e. if a character
6505 -- literal is accepted by the parser, then it is OK for wide wide
6506 -- character (out of range character literals are rejected).
6511 -- Always accept character literal for type Any_Character, which
6512 -- occurs in error situations and in comparisons of literals, both
6513 -- of which should accept all literals.
6518 -- For Standard.Character or a type derived from it, check that the
6519 -- literal is in range.
6526 -- For Standard.Wide_Character or a type derived from it, check that the
6527 -- literal is in range.
6534 -- For Standard.Wide_Wide_Character or a type derived from it, we
6535 -- know the literal is in range, since the parser checked.
6540 -- If the entity is already set, this has already been resolved in a
6541 -- generic context, or comes from expansion. Nothing else to do.
6546 -- Otherwise we have a user defined character type, and we can use the
6547 -- standard visibility mechanisms to locate the referenced entity.
6549 else
6562 -- If we fall through, then the literal does not match any of the
6563 -- entries of the enumeration type. This isn't just a constraint error
6564 -- situation, it is an illegality (see RM 4.2).
6566 Error_Msg_NE
6570 ---------------------------
6571 -- Resolve_Comparison_Op --
6572 ---------------------------
6574 -- Context requires a boolean type, and plays no role in resolution.
6575 -- Processing identical to that for equality operators. The result type is
6576 -- the base type, which matters when pathological subtypes of booleans with
6577 -- limited ranges are used.
6584 begin
6585 -- If this is an intrinsic operation which is not predefined, use the
6586 -- types of its declared arguments to resolve the possibly overloaded
6587 -- operands. Otherwise the operands are unambiguous and specify the
6588 -- expected type.
6593 else
6604 -- Skip remaining processing if already set to Any_Type
6610 -- Deal with other error cases
6614 T = Any_Character
6615 then
6618 else
6626 -- Resolve the operands if types OK
6635 -- In SPARK, ordering operators <, <=, >, >= are not defined for Boolean
6636 -- types or array types except String.
6639 Check_SPARK_05_Restriction
6644 then
6645 Check_SPARK_05_Restriction
6649 -- Check comparison on unordered enumeration
6653 Error_Msg_NE
6658 -- Evaluate the relation (note we do this after the above check since
6659 -- this Eval call may change N to True/False.
6665 -----------------------------------------
6666 -- Resolve_Discrete_Subtype_Indication --
6667 -----------------------------------------
6669 procedure Resolve_Discrete_Subtype_Indication
6672 is
6676 begin
6684 else
6694 Error_Msg_NE
6697 -- Rewrite the constraint as a range of Typ
6698 -- to allow compilation to proceed further.
6710 else
6714 -- Additionally, we must check that the bounds are compatible
6715 -- with the given subtype, which might be different from the
6716 -- type of the context.
6720 -- ??? If the above check statically detects a Constraint_Error
6721 -- it replaces the offending bound(s) of the range R with a
6722 -- Constraint_Error node. When the itype which uses these bounds
6723 -- is frozen the resulting call to Duplicate_Subexpr generates
6724 -- a new temporary for the bounds.
6726 -- Unfortunately there are other itypes that are also made depend
6727 -- on these bounds, so when Duplicate_Subexpr is called they get
6728 -- a forward reference to the newly created temporaries and Gigi
6729 -- aborts on such forward references. This is probably sign of a
6730 -- more fundamental problem somewhere else in either the order of
6731 -- itype freezing or the way certain itypes are constructed.
6733 -- To get around this problem we call Remove_Side_Effects right
6734 -- away if either bounds of R are a Constraint_Error.
6736 declare
6740 begin
6756 -------------------------
6757 -- Resolve_Entity_Name --
6758 -------------------------
6760 -- Used to resolve identifiers and expanded names
6763 function Is_Assignment_Or_Object_Expression
6766 -- Determine whether node Context denotes an assignment statement or an
6767 -- object declaration whose expression is node Expr.
6769 function Is_OK_Volatile_Context
6772 -- Determine whether node Context denotes a "non-interfering context"
6773 -- (as defined in SPARK RM 7.1.3(13)) where volatile reference Obj_Ref
6774 -- can safely reside.
6776 ----------------------------------------
6777 -- Is_Assignment_Or_Object_Expression --
6778 ----------------------------------------
6780 function Is_Assignment_Or_Object_Expression
6783 is
6784 begin
6786 N_Object_Declaration)
6788 then
6791 -- Check whether a construct that yields a name is the expression of
6792 -- an assignment statement or an object declaration.
6795 N_Explicit_Dereference,
6796 N_Indexed_Component,
6797 N_Selected_Component,
6798 N_Slice)
6800 or else
6802 N_Unchecked_Type_Conversion)
6804 then
6805 return
6806 Is_Assignment_Or_Object_Expression
6810 -- Otherwise the context is not an assignment statement or an object
6811 -- declaration.
6813 else
6818 ----------------------------
6819 -- Is_OK_Volatile_Context --
6820 ----------------------------
6822 function Is_OK_Volatile_Context
6825 is
6827 -- Determine whether an arbitrary node appears in a check node
6830 -- Determine whether an arbitrary node appears in a procedure call
6832 ------------------
6833 -- Within_Check --
6834 ------------------
6839 begin
6840 -- Climb the parent chain looking for a check node
6847 -- Prevent the search from going too far
6859 ---------------------------
6860 -- Within_Procedure_Call --
6861 ---------------------------
6866 begin
6867 -- Climb the parent chain looking for a procedure call
6874 -- Prevent the search from going too far
6886 -- Start of processing for Is_OK_Volatile_Context
6888 begin
6889 -- The volatile object appears on either side of an assignment
6894 -- The volatile object is part of the initialization expression of
6895 -- another object. Ensure that the climb of the parent chain came
6896 -- from the expression side and not from the name side.
6901 then
6904 -- The volatile object appears as an actual parameter in a call to an
6905 -- instance of Unchecked_Conversion whose result is renamed.
6910 then
6913 -- The volatile object appears as the prefix of a name occurring
6914 -- in a non-interfering context.
6917 N_Explicit_Dereference,
6918 N_Indexed_Component,
6919 N_Selected_Component,
6920 N_Slice)
6922 and then Is_OK_Volatile_Context
6925 then
6928 -- The volatile object appears as the expression of a type conversion
6929 -- occurring in a non-interfering context.
6932 N_Unchecked_Type_Conversion)
6934 and then Is_OK_Volatile_Context
6937 then
6940 -- Allow references to volatile objects in various checks. This is
6941 -- not a direct SPARK 2014 requirement.
6946 -- Assume that references to effectively volatile objects that appear
6947 -- as actual parameters in a procedure call are always legal. A full
6948 -- legality check is done when the actuals are resolved.
6953 -- Otherwise the context is not suitable for an effectively volatile
6954 -- object.
6956 else
6961 -- Local variables
6966 -- Start of processing for Resolve_Entity_Name
6968 begin
6969 -- If garbage from errors, set to Any_Type and return
6976 -- Replace named numbers by corresponding literals. Note that this is
6977 -- the one case where Resolve_Entity_Name must reset the Etype, since
6978 -- it is currently marked as universal.
6988 -- For enumeration literals, we need to make sure that a proper style
6989 -- check is done, since such literals are overloaded, and thus we did
6990 -- not do a style check during the first phase of analysis.
6996 -- Case of (sub)type name appearing in a context where an expression
6997 -- is expected. This is legal if occurrence is a current instance.
6998 -- See RM 8.6 (17/3).
7004 -- Any other use is an error
7006 else
7007 Error_Msg_N
7011 -- Check discriminant use if entity is discriminant in current scope,
7012 -- i.e. discriminant of record or concurrent type currently being
7013 -- analyzed. Uses in corresponding body are unrestricted.
7018 then
7021 -- A parameterless generic function cannot appear in a context that
7022 -- requires resolution.
7027 -- In Ada 83 an OUT parameter cannot be read
7032 or else Is_Assignment_Or_Object_Expression
7035 then
7039 -- An effectively volatile OUT parameter cannot be read
7040 -- (SPARK RM 7.1.3(11)).
7044 then
7048 -- In all other cases, just do the possible static evaluation
7050 else
7051 -- A deferred constant that appears in an expression must have a
7052 -- completion, unless it has been removed by in-place expansion of
7053 -- an aggregate.
7059 and then not In_Spec_Expression
7061 then
7065 then
7067 else
7068 Error_Msg_N (
7078 -- When the entity appears in a parameter association, retrieve the
7079 -- related subprogram call.
7085 -- The following checks are only relevant when SPARK_Mode is on as they
7086 -- are not standard Ada legality rules. An effectively volatile object
7087 -- subject to enabled properties Async_Writers or Effective_Reads must
7088 -- appear in a specific context.
7096 then
7097 -- The effectively volatile objects appears in a "non-interfering
7098 -- context" as defined in SPARK RM 7.1.3(13).
7103 -- Otherwise the context causes a side effect with respect to the
7104 -- effectively volatile object.
7106 else
7107 SPARK_Msg_N
7113 -- A Ghost entity must appear in a specific context
7119 -- In SPARK mode, need to check possible elaboration issues
7126 -------------------
7127 -- Resolve_Entry --
7128 -------------------
7140 -- If the bounds of the entry family being called depend on task
7141 -- discriminants, build a new index subtype where a discriminant is
7142 -- replaced with the value of the discriminant of the target task.
7143 -- The target task is the prefix of the entry name in the call.
7145 -----------------------
7146 -- Actual_Index_Type --
7147 -----------------------
7157 -- If the bound is given by a discriminant, replace with a reference
7158 -- to the discriminant of the same name in the target task. If the
7159 -- entry name is the target of a requeue statement and the entry is
7160 -- in the current protected object, the bound to be used is the
7161 -- discriminal of the object (see Apply_Range_Checks for details of
7162 -- the transformation).
7164 -----------------------------
7165 -- Actual_Discriminant_Ref --
7166 -----------------------------
7172 begin
7177 then
7183 then
7184 -- Note: here Bound denotes a discriminant of the corresponding
7185 -- record type tskV, whose discriminal is a formal of the
7186 -- init-proc tskVIP. What we want is the body discriminal,
7187 -- which is associated to the discriminant of the original
7188 -- concurrent type tsk.
7190 return New_Occurrence_Of
7193 else
7194 Ref :=
7204 -- Start of processing for Actual_Index_Type
7206 begin
7209 then
7212 else
7226 -- Start of processing of Resolve_Entry
7228 begin
7229 -- Find name of entry being called, and resolve prefix of name with its
7230 -- own type. The prefix can be overloaded, and the name and signature of
7231 -- the entry must be taken into account.
7235 -- Case of dealing with entry family within the current tasks
7239 else
7245 -- Entry call to an entry (or entry family) in the current task. This
7246 -- is legal even though the task will deadlock. Rewrite as call to
7247 -- current task.
7249 -- This can also be a call to an entry in an enclosing task. If this
7250 -- is a single task, we have to retrieve its name, because the scope
7251 -- of the entry is the task type, not the object. If the enclosing
7252 -- task is a task type, the identity of the task is given by its own
7253 -- self variable.
7255 -- Finally this can be a requeue on an entry of the same task or
7256 -- protected object.
7263 then
7264 -- S is an enclosing task or protected object. The concurrent
7265 -- declaration has been converted into a type declaration, and
7266 -- the object itself has an object declaration that follows
7267 -- the type in the same declarative part.
7279 -- Call to current task. Will be transformed into call to Self
7286 New_N :=
7289 Selector_Name =>
7296 then
7297 -- Use the entry name (which must be unique at this point) to find
7298 -- the prefix that returns the corresponding task/protected type.
7300 declare
7306 begin
7328 -- Up to this point the expression could have been the actual in a
7329 -- simple entry call, and be given by a named association.
7333 else
7339 ------------------------
7340 -- Resolve_Entry_Call --
7341 ------------------------
7353 begin
7354 -- We kill all checks here, because it does not seem worth the effort to
7355 -- do anything better, an entry call is a big operation.
7357 Kill_All_Checks;
7359 -- Processing of the name is similar for entry calls and protected
7360 -- operation calls. Once the entity is determined, we can complete
7361 -- the resolution of the actuals.
7363 -- The selector may be overloaded, in the case of a protected object
7364 -- with overloaded functions. The type of the context is used for
7365 -- resolution.
7370 then
7371 declare
7375 begin
7394 -- Simple entry call
7402 -- Call to member of entry family
7409 -- We cannot in general check the maximum depth of protected entry calls
7410 -- at compile time. But we can tell that any protected entry call at all
7411 -- violates a specified nesting depth of zero.
7417 -- Use context type to disambiguate a protected function that can be
7418 -- called without actuals and that returns an array type, and where the
7419 -- argument list may be an indexing of the returned value.
7424 and then
7430 and then
7431 Covers
7434 then
7435 declare
7438 begin
7439 Index_Node :=
7441 Prefix =>
7445 -- Since we are correcting a node classification error made by the
7446 -- parser, we call Replace rather than Rewrite.
7459 then
7460 -- Rewrite as call to the precondition wrapper, adding the task
7461 -- object to the list of actuals. If the call is to a member of an
7462 -- entry family, include the index as well.
7464 declare
7468 begin
7477 New_Call :=
7479 Name =>
7484 -- Preanalyze and resolve new call. Current procedure is called
7485 -- from Resolve_Call, after which expansion will take place.
7492 -- The operation name may have been overloaded. Order the actuals
7493 -- according to the formals of the resolved entity, and set the return
7494 -- type to that of the operation.
7505 -- Create a call reference to the entry
7513 -- Verify that a procedure call cannot masquerade as an entry
7514 -- call where an entry call is expected.
7519 then
7524 then
7529 then
7534 -- After resolution, entry calls and protected procedure calls are
7535 -- changed into entry calls, for expansion. The structure of the node
7536 -- does not change, so it can safely be done in place. Protected
7537 -- function calls must keep their structure because they are
7538 -- subexpressions.
7542 -- A protected operation that is not a function may modify the
7543 -- corresponding object, and cannot apply to a constant. If this
7544 -- is an internal call, the prefix is the type itself.
7550 then
7551 Error_Msg_N
7553 Entry_Name);
7567 -- Protected functions can return on the secondary stack, in which
7568 -- case we must trigger the transient scope mechanism.
7570 elsif Expander_Active
7572 then
7577 -------------------------
7578 -- Resolve_Equality_Op --
7579 -------------------------
7581 -- Both arguments must have the same type, and the boolean context does
7582 -- not participate in the resolution. The first pass verifies that the
7583 -- interpretation is not ambiguous, and the type of the left argument is
7584 -- correctly set, or is Any_Type in case of ambiguity. If both arguments
7585 -- are strings or aggregates, allocators, or Null, they are ambiguous even
7586 -- though they carry a single (universal) type. Diagnose this case here.
7594 -- The resolution rule for if expressions requires that each such must
7595 -- have a unique type. This means that if several dependent expressions
7596 -- are of a non-null anonymous access type, and the context does not
7597 -- impose an expected type (as can be the case in an equality operation)
7598 -- the expression must be rejected.
7601 -- Attempt to explain the nature of a redundant comparison with True. If
7602 -- the expression N is too complex, this routine issues a general error
7603 -- message.
7606 -- In the case of allocators and access attributes, the context must
7607 -- provide an indication of the specific access type to be used. If
7608 -- one operand is of such a "generic" access type, check whether there
7609 -- is a specific visible access type that has the same designated type.
7610 -- This is semantically dubious, and of no interest to any real code,
7611 -- but c48008a makes it all worthwhile.
7613 -------------------------
7614 -- Check_If_Expression --
7615 -------------------------
7621 begin
7628 then
7634 ------------------------
7635 -- Explain_Redundancy --
7636 ------------------------
7643 begin
7646 -- Strip the operand down to an entity
7648 loop
7651 else
7656 -- The construct denotes an entity
7661 -- Do not generate an error message when the comparison is done
7662 -- against the enumeration literal Standard.True.
7666 -- Build a customized error message
7693 -- The construct is too complex to disect, issue a general message
7695 else
7700 -----------------------------
7701 -- Find_Unique_Access_Type --
7702 -----------------------------
7709 begin
7711 E_Access_Attribute_Type)
7712 then
7716 E_Access_Attribute_Type)
7717 then
7719 else
7731 then
7744 -- Start of processing for Resolve_Equality_Op
7746 begin
7757 T = Any_Character
7758 then
7761 else
7770 then
7779 -- If expressions must have a single type, and if the context does
7780 -- not impose one the dependent expressions cannot be anonymous
7781 -- access types.
7783 -- Why no similar processing for case expressions???
7787 E_Anonymous_Access_Subprogram_Type)
7789 E_Anonymous_Access_Subprogram_Type)
7790 then
7798 -- In SPARK, equality operators = and /= for array types other than
7799 -- String are only defined when, for each index position, the
7800 -- operands have equal static bounds.
7804 -- Protect call to Matching_Static_Array_Bounds to avoid costly
7805 -- operation if not needed.
7813 then
7814 Check_SPARK_05_Restriction
7819 -- If the unique type is a class-wide type then it will be expanded
7820 -- into a dispatching call to the predefined primitive. Therefore we
7821 -- check here for potential violation of such restriction.
7827 if Warn_On_Redundant_Constructs
7832 then
7833 Error_Msg_N -- CODEFIX
7843 -- If this is an inequality, it may be the implicit inequality
7844 -- created for a user-defined operation, in which case the corres-
7845 -- ponding equality operation is not intrinsic, and the operation
7846 -- cannot be constant-folded. Else fold.
7851 or else Is_Intrinsic_Subprogram
7853 then
7859 then
7863 -- Ada 2005: If one operand is an anonymous access type, convert the
7864 -- other operand to it, to ensure that the underlying types match in
7865 -- the back-end. Same for access_to_subprogram, and the conversion
7866 -- verifies that the types are subtype conformant.
7868 -- We apply the same conversion in the case one of the operands is a
7869 -- private subtype of the type of the other.
7871 -- Why the Expander_Active test here ???
7873 if Expander_Active
7874 and then
7876 E_Anonymous_Access_Subprogram_Type)
7878 then
7898 ----------------------------------
7899 -- Resolve_Explicit_Dereference --
7900 ----------------------------------
7908 -- The candidate prefix type, if overloaded
7913 begin
7917 -- A useful optimization: check whether the dereference denotes an
7918 -- element of a container, and if so rewrite it as a call to the
7919 -- corresponding Element function.
7921 -- Disabled for now, on advice of ARG. A more restricted form of the
7922 -- predicate might be acceptable ???
7924 -- if Is_Container_Element (N) then
7925 -- return;
7926 -- end if;
7930 -- Use the context type to select the prefix that has the correct
7931 -- designated type. Keep the first match, which will be the inner-
7932 -- most.
7939 then
7944 -- Remove access types that do not match, but preserve access
7945 -- to subprogram interpretations, in case a further dereference
7946 -- is needed (see below).
7959 else
7960 -- If no interpretation covers the designated type of the prefix,
7961 -- this is the pathological case where not all implementations of
7962 -- the prefix allow the interpretation of the node as a call. Now
7963 -- that the expected type is known, Remove other interpretations
7964 -- from prefix, rewrite it as a call, and resolve again, so that
7965 -- the proper call node is generated.
7976 New_N :=
7978 Name =>
7989 -- If not overloaded, resolve P with its own type
7991 else
7999 -- If the designated type is a packed unconstrained array type, and the
8000 -- explicit dereference is not in the context of an attribute reference,
8001 -- then we must compute and set the actual subtype, since it is needed
8002 -- by Gigi. The reason we exclude the attribute case is that this is
8003 -- handled fine by Gigi, and in fact we use such attributes to build the
8004 -- actual subtype. We also exclude generated code (which builds actual
8005 -- subtypes directly if they are needed).
8012 then
8016 -- Note: No Eval processing is required for an explicit dereference,
8017 -- because such a name can never be static.
8021 -------------------------------------
8022 -- Resolve_Expression_With_Actions --
8023 -------------------------------------
8026 begin
8029 -- If N has no actions, and its expression has been constant folded,
8030 -- then rewrite N as just its expression. Note, we can't do this in
8031 -- the general case of Is_Empty_List (Actions (N)) as this would cause
8032 -- Expression (N) to be expanded again.
8036 then
8041 ----------------------------------
8042 -- Resolve_Generalized_Indexing --
8043 ----------------------------------
8051 begin
8052 -- In ASIS mode, propagate the information about the indexes back to
8053 -- to the original indexing node. The generalized indexing is either
8054 -- a function call, or a dereference of one. The actuals include the
8055 -- prefix of the original node, which is the container expression.
8064 loop
8075 else
8081 ---------------------------
8082 -- Resolve_If_Expression --
8083 ---------------------------
8092 begin
8097 -- When the "then" expression is of a scalar subtype different from the
8098 -- result subtype, then insert a conversion to ensure the generation of
8099 -- a constraint check. The same is done for the else part below, again
8100 -- comparing subtypes rather than base types.
8104 then
8109 -- If ELSE expression present, just resolve using the determined type
8119 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
8120 -- dynamically tagged must be known statically.
8125 then
8131 -- If no ELSE expression is present, root type must be Standard.Boolean
8132 -- and we provide a Standard.True result converted to the appropriate
8133 -- Boolean type (in case it is a derived boolean type).
8136 Else_Expr :=
8141 else
8150 -------------------------------
8151 -- Resolve_Indexed_Component --
8152 -------------------------------
8160 begin
8168 -- Use the context type to select the prefix that yields the correct
8169 -- component type.
8171 declare
8178 begin
8185 and then
8186 Covers
8189 then
8198 else
8204 else
8215 else
8222 -- If prefix is access type, dereference to get real array type.
8223 -- Note: we do not apply an access check because the expander always
8224 -- introduces an explicit dereference, and the check will happen there.
8230 -- If name was overloaded, set component type correctly now
8231 -- If a misplaced call to an entry family (which has no index types)
8232 -- return. Error will be diagnosed from calling context.
8236 else
8243 -- The prefix may have resolved to a string literal, in which case its
8244 -- etype has a special representation. This is only possible currently
8245 -- if the prefix is a static concatenation, written in functional
8246 -- notation.
8251 else
8258 else
8269 -- Do not generate the warning on suspicious index if we are analyzing
8270 -- package Ada.Tags; otherwise we will report the warning with the
8271 -- Prims_Ptr field of the dispatch table.
8274 or else not
8276 Ada_Tags)
8277 then
8282 -- If the array type is atomic, and the component is not atomic, then
8283 -- this is worth a warning, since we have a situation where the access
8284 -- to the component may cause extra read/writes of the atomic array
8285 -- object, or partial word accesses, which could be unexpected.
8291 and then Has_Atomic_Components
8294 then
8295 Error_Msg_N
8297 Error_Msg_N
8302 -----------------------------
8303 -- Resolve_Integer_Literal --
8304 -----------------------------
8307 begin
8312 --------------------------------
8313 -- Resolve_Intrinsic_Operator --
8314 --------------------------------
8323 -- If the operand is a literal, it cannot be the expression in a
8324 -- conversion. Use a qualified expression instead.
8326 ---------------------
8327 -- Convert_Operand --
8328 ---------------------
8334 begin
8336 Res :=
8342 else
8349 -- Start of processing for Resolve_Intrinsic_Operator
8351 begin
8352 -- We must preserve the original entity in a generic setting, so that
8353 -- the legality of the operation can be verified in an instance.
8368 -- If the result or operand types are private, rewrite with unchecked
8369 -- conversions on the operands and the result, to expose the proper
8370 -- underlying numeric type.
8375 then
8380 else
8401 then
8402 -- Add explicit conversion where needed, and save interpretations in
8403 -- case operands are overloaded.
8410 else
8416 else
8426 else
8431 --------------------------------------
8432 -- Resolve_Intrinsic_Unary_Operator --
8433 --------------------------------------
8435 procedure Resolve_Intrinsic_Unary_Operator
8438 is
8443 begin
8462 else
8467 ------------------------
8468 -- Resolve_Logical_Op --
8469 ------------------------
8474 begin
8477 -- Predefined operations on scalar types yield the base type. On the
8478 -- other hand, logical operations on arrays yield the type of the
8479 -- arguments (and the context).
8483 else
8487 -- The following test is required because the operands of the operation
8488 -- may be literals, in which case the resulting type appears to be
8489 -- compatible with a signed integer type, when in fact it is compatible
8490 -- only with modular types. If the context itself is universal, the
8491 -- operation is illegal.
8499 Error_Msg_N
8507 then
8511 -- Replace AND by AND THEN, or OR by OR ELSE, if Short_Circuit_And_Or
8512 -- is active and the result type is standard Boolean (do not mess with
8513 -- ops that return a nonstandard Boolean type, because something strange
8514 -- is going on).
8516 -- Note: you might expect this replacement to be done during expansion,
8517 -- but that doesn't work, because when the pragma Short_Circuit_And_Or
8518 -- is used, no part of the right operand of an "and" or "or" operator
8519 -- should be executed if the left operand would short-circuit the
8520 -- evaluation of the corresponding "and then" or "or else". If we left
8521 -- the replacement to expansion time, then run-time checks associated
8522 -- with such operands would be evaluated unconditionally, due to being
8523 -- before the condition prior to the rewriting as short-circuit forms
8524 -- during expansion.
8526 if Short_Circuit_And_Or
8529 then
8530 -- Mark the corresponding putative SCO operator as truly a logical
8531 -- (and short-circuit) operator.
8544 -- Case of OR changed to OR ELSE
8546 else
8554 -- Return now, since analysis of the rewritten ops will take care of
8555 -- other reference bookkeeping and expression folding.
8570 -- In SPARK, logical operations AND, OR and XOR for arrays are defined
8571 -- only when both operands have same static lower and higher bounds. Of
8572 -- course the types have to match, so only check if operands are
8573 -- compatible and the node itself has no errors.
8577 then
8578 declare
8582 begin
8583 -- Protect call to Matching_Static_Array_Bounds to avoid costly
8584 -- operation if not needed.
8591 then
8592 Check_SPARK_05_Restriction
8599 ---------------------------
8600 -- Resolve_Membership_Op --
8601 ---------------------------
8603 -- The context can only be a boolean type, and does not determine the
8604 -- arguments. Arguments should be unambiguous, but the preference rule for
8605 -- universal types applies.
8615 -- Analysis has determined a unique type for the left operand. Use it to
8616 -- resolve the disjuncts.
8618 ----------------------------
8619 -- Resolve_Set_Membership --
8620 ----------------------------
8626 begin
8627 -- If the left operand is overloaded, find type compatible with not
8628 -- overloaded alternative of the right operand.
8637 else
8642 -- Unclear how to resolve expression if all alternatives are also
8643 -- overloaded.
8649 else
8658 -- Alternative is an expression, a range
8659 -- or a subtype mark.
8663 then
8670 -- Check for duplicates for discrete case
8673 declare
8682 begin
8683 -- Loop checking duplicates. This is quadratic, but giant sets
8684 -- are unlikely in this context so it's a reasonable choice.
8691 N_Character_Literal)
8693 then
8711 -- Start of processing for Resolve_Membership_Op
8713 begin
8719 Resolve_Set_Membership;
8723 and then
8725 or else
8728 then
8731 -- Ada 2005 (AI-251): Support the following case:
8733 -- type I is interface;
8734 -- type T is tagged ...
8736 -- function Test (O : I'Class) is
8737 -- begin
8738 -- return O in T'Class.
8739 -- end Test;
8741 -- In this case we have nothing else to do. The membership test will be
8742 -- done at run time.
8749 then
8751 else
8755 -- If mixed-mode operations are present and operands are all literal,
8756 -- the only interpretation involves Duration, which is probably not
8757 -- the intention of the programmer.
8772 then
8778 else
8783 -- Here after resolving membership operation
8790 ------------------
8791 -- Resolve_Null --
8792 ------------------
8797 begin
8798 -- Handle restriction against anonymous null access values This
8799 -- restriction can be turned off using -gnatdj.
8801 -- Ada 2005 (AI-231): Remove restriction
8804 and then not Debug_Flag_J
8807 then
8808 -- In the common case of a call which uses an explicitly null value
8809 -- for an access parameter, give specialized error message.
8812 Error_Msg_N
8815 -- Standard message for all other cases (are there any?)
8817 else
8818 Error_Msg_N
8823 -- Ada 2005 (AI-231): Generate the null-excluding check in case of
8824 -- assignment to a null-excluding object
8829 then
8831 Insert_Action
8836 else
8843 -- In a distributed context, null for a remote access to subprogram may
8844 -- need to be replaced with a special record aggregate. In this case,
8845 -- return after having done the transformation.
8850 then
8854 -- The null literal takes its type from the context
8859 -----------------------
8860 -- Resolve_Op_Concat --
8861 -----------------------
8865 -- We wish to avoid deep recursion, because concatenations are often
8866 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
8867 -- operands nonrecursively until we find something that is not a simple
8868 -- concatenation (A in this case). We resolve that, and then walk back
8869 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
8870 -- to do the rest of the work at each level. The Parent pointers allow
8871 -- us to avoid recursion, and thus avoid running out of memory. See also
8872 -- Sem_Ch4.Analyze_Concatenation, where a similar approach is used.
8877 begin
8878 -- The following code is equivalent to:
8880 -- Resolve_Op_Concat_First (NN, Typ);
8881 -- Resolve_Op_Concat_Arg (N, ...);
8882 -- Resolve_Op_Concat_Rest (N, Typ);
8884 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
8885 -- operand is a concatenation.
8887 -- Walk down left operands
8889 loop
8898 -- Now (given the above example) NN is A&B and Op1 is A
8900 -- First resolve Op1 ...
8904 -- ... then walk NN back up until we reach N (where we started), calling
8905 -- Resolve_Op_Concat_Rest along the way.
8907 loop
8914 Check_SPARK_05_Restriction
8919 ---------------------------
8920 -- Resolve_Op_Concat_Arg --
8921 ---------------------------
8923 procedure Resolve_Op_Concat_Arg
8928 is
8932 begin
8934 if Is_Comp
8938 then
8940 else
8944 -- If both Array & Array and Array & Component are visible, there is a
8945 -- potential ambiguity that must be reported.
8950 then
8954 -- If the operation is user-defined and not overloaded use its
8955 -- profile. The operation may be a renaming, in which case it has
8956 -- been rewritten, and we want the original profile.
8961 then
8963 Etype
8967 -- Otherwise an aggregate may match both the array type and the
8968 -- component type.
8970 else
8975 else
8979 then
8980 declare
8985 begin
8990 -- Special-case the error message when the overloading is
8991 -- caused by a function that yields an array and can be
8992 -- called without parameters.
8997 Error_Msg_NE
8999 Error_Msg_NE
9003 else
9011 or else
9013 then
9014 Error_Msg_N -- CODEFIX
9032 else
9037 else
9041 -- Concatenation is restricted in SPARK: each operand must be either a
9042 -- string literal, the name of a string constant, a static character or
9043 -- string expression, or another concatenation. Arg cannot be a
9044 -- concatenation here as callers of Resolve_Op_Concat_Arg call it
9045 -- separately on each final operand, past concatenation operations.
9049 Check_SPARK_05_Restriction
9057 then
9058 Check_SPARK_05_Restriction
9062 -- Do not issue error on an operand that is neither a character nor a
9063 -- string, as the error is issued in Resolve_Op_Concat.
9065 else
9072 -----------------------------
9073 -- Resolve_Op_Concat_First --
9074 -----------------------------
9081 begin
9082 -- The parser folds an enormous sequence of concatenations of string
9083 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
9084 -- in the right operand. If the expression resolves to a predefined "&"
9085 -- operator, all is well. Otherwise, the parser's folding is wrong, so
9086 -- we give an error. See P_Simple_Expression in Par.Ch4.
9091 then
9106 ----------------------------
9107 -- Resolve_Op_Concat_Rest --
9108 ----------------------------
9114 begin
9123 -- If this is not a static concatenation, but the result is a string
9124 -- type (and not an array of strings) ensure that static string operands
9125 -- have their subtypes properly constructed.
9129 then
9135 ----------------------
9136 -- Resolve_Op_Expon --
9137 ----------------------
9142 begin
9143 -- Catch attempts to do fixed-point exponentiation with universal
9144 -- operands, which is a case where the illegality is not caught during
9145 -- normal operator analysis. This is not done in preanalysis mode
9146 -- since the tree is not fully decorated during preanalysis.
9157 then
9167 then
9174 then
9178 -- We do the resolution using the base type, because intermediate values
9179 -- in expressions are always of the base type, not a subtype of it.
9184 -- For integer types, right argument must be in Natural range
9199 -- Evaluate the exponentiation operator for dimensioned type
9202 else
9206 -- Set overflow checking bit. Much cleverer code needed here eventually
9207 -- and perhaps the Resolve routines should be separated for the various
9208 -- arithmetic operations, since they will need different processing. ???
9217 --------------------
9218 -- Resolve_Op_Not --
9219 --------------------
9225 -- This function determines if the parent node is a boolean operator or
9226 -- operation (comparison op, membership test, or short circuit form) and
9227 -- the not in question is the left operand of this operation. Note that
9228 -- if the not is in parens, then false is returned.
9230 -----------------------
9231 -- Parent_Is_Boolean --
9232 -----------------------
9235 begin
9239 else
9241 when N_Op_And |
9242 N_Op_Eq |
9243 N_Op_Ge |
9244 N_Op_Gt |
9245 N_Op_Le |
9246 N_Op_Lt |
9247 N_Op_Ne |
9248 N_Op_Or |
9249 N_Op_Xor |
9250 N_In |
9251 N_Not_In |
9252 N_And_Then |
9253 N_Or_Else =>
9263 -- Start of processing for Resolve_Op_Not
9265 begin
9266 -- Predefined operations on scalar types yield the base type. On the
9267 -- other hand, logical operations on arrays yield the type of the
9268 -- arguments (and the context).
9272 else
9276 -- Straightforward case of incorrect arguments
9283 -- Special case of probable missing parens
9287 Error_Msg_N
9290 else
9291 Error_Msg_N
9298 -- OK resolution of NOT
9300 else
9301 -- Warn if non-boolean types involved. This is a case like not a < b
9302 -- where a and b are modular, where we will get (not a) < b and most
9303 -- likely not (a < b) was intended.
9305 if Warn_On_Questionable_Missing_Parens
9307 and then Parent_Is_Boolean
9308 then
9312 -- Warn on double negation if checking redundant constructs
9314 if Warn_On_Redundant_Constructs
9319 then
9323 -- Complete resolution and evaluation of NOT
9333 -----------------------------
9334 -- Resolve_Operator_Symbol --
9335 -----------------------------
9337 -- Nothing to be done, all resolved already
9343 begin
9347 ----------------------------------
9348 -- Resolve_Qualified_Expression --
9349 ----------------------------------
9357 begin
9360 -- Protect call to Matching_Static_Array_Bounds to avoid costly
9361 -- operation if not needed.
9368 then
9369 Check_SPARK_05_Restriction
9373 -- A qualified expression requires an exact match of the type, class-
9374 -- wide matching is not allowed. However, if the qualifying type is
9375 -- specific and the expression has a class-wide type, it may still be
9376 -- okay, since it can be the result of the expansion of a call to a
9377 -- dispatching function, so we also have to check class-wideness of the
9378 -- type of the expression's original node.
9381 or else
9385 then
9389 -- If the target type is unconstrained, then we reset the type of the
9390 -- result from the type of the expression. For other cases, the actual
9391 -- subtype of the expression is the target type.
9395 then
9402 -- If we still have a qualified expression after the static evaluation,
9403 -- then apply a scalar range check if needed. The reason that we do this
9404 -- after the Eval call is that otherwise, the application of the range
9405 -- check may convert an illegal static expression and result in warning
9406 -- rather than giving an error (e.g Integer'(Integer'Last + 1)).
9413 ------------------------------
9414 -- Resolve_Raise_Expression --
9415 ------------------------------
9418 begin
9422 else
9427 -------------------
9428 -- Resolve_Range --
9429 -------------------
9436 -- Returns True if N is of the form X'First .. X'Last where X is the
9437 -- same entity for both attributes.
9439 --------------------
9440 -- First_Last_Ref --
9441 --------------------
9447 begin
9452 then
9453 declare
9456 begin
9460 then
9469 -- Start of processing for Resolve_Range
9471 begin
9476 -- Check for inappropriate range on unordered enumeration type
9480 -- Exclude X'First .. X'Last if X is the same entity for both
9482 and then not First_Last_Ref
9483 then
9485 Error_Msg_NE
9492 -- We have to check the bounds for being within the base range as
9493 -- required for a non-static context. Normally this is automatic and
9494 -- done as part of evaluating expressions, but the N_Range node is an
9495 -- exception, since in GNAT we consider this node to be a subexpression,
9496 -- even though in Ada it is not. The circuit in Sem_Eval could check for
9497 -- this, but that would put the test on the main evaluation path for
9498 -- expressions.
9503 -- Check for an ambiguous range over character literals. This will
9504 -- happen with a membership test involving only literals.
9512 -- If bounds are static, constant-fold them, so size computations are
9513 -- identical between front-end and back-end. Do not perform this
9514 -- transformation while analyzing generic units, as type information
9515 -- would be lost when reanalyzing the constant node in the instance.
9528 --------------------------
9529 -- Resolve_Real_Literal --
9530 --------------------------
9535 begin
9536 -- Special processing for fixed-point literals to make sure that the
9537 -- value is an exact multiple of small where this is required. We skip
9538 -- this for the universal real case, and also for generic types.
9544 then
9545 declare
9552 begin
9553 -- Case of literal is not an exact multiple of the Small
9557 -- For a source program literal for a decimal fixed-point type,
9558 -- this is statically illegal (RM 4.9(36)).
9563 then
9567 -- Generate a warning if literal from source
9570 and then Warn_On_Bad_Fixed_Value
9571 then
9572 Error_Msg_N
9574 N);
9577 -- Replace literal by a value that is the exact representation
9578 -- of a value of the type, i.e. a multiple of the small value,
9579 -- by truncation, since Machine_Rounds is false for all GNAT
9580 -- fixed-point types (RM 4.9(38)).
9590 -- In all cases, set the corresponding integer field
9596 -- Now replace the actual type by the expected type as usual
9602 -----------------------
9603 -- Resolve_Reference --
9604 -----------------------
9609 begin
9610 -- Replace general access with specific type
9618 -- If we are taking the reference of a volatile entity, then treat it as
9619 -- a potential modification of this entity. This is too conservative,
9620 -- but necessary because remove side effects can cause transformations
9621 -- of normal assignments into reference sequences that otherwise fail to
9622 -- notice the modification.
9629 --------------------------------
9630 -- Resolve_Selected_Component --
9631 --------------------------------
9646 -- Check whether this is the initialization of a component within an
9647 -- init proc (by assignment or call to another init proc). If true,
9648 -- there is no need for a discriminant check.
9650 --------------------
9651 -- Init_Component --
9652 --------------------
9655 begin
9656 return Inside_Init_Proc
9662 -- Start of processing for Resolve_Selected_Component
9664 begin
9667 -- Use the context type to select the prefix that has a selector
9668 -- of the correct name and type.
9676 else
9680 -- Locate selected component. For a private prefix the selector
9681 -- can denote a discriminant.
9685 -- The visible components of a class-wide type are those of
9686 -- the root type.
9696 then
9703 else
9707 Error_Msg_N
9712 else
9715 -- There may be an implicit dereference. Retrieve
9716 -- designated record type.
9720 else
9726 -- Resolution chooses the new interpretation.
9727 -- Find the component with the right name.
9732 loop
9749 -- There must be a legal interpretation at this point
9756 else
9757 -- Resolve prefix with its type
9762 -- Generate cross-reference. We needed to wait until full overloading
9763 -- resolution was complete to do this, since otherwise we can't tell if
9764 -- we are an lvalue or not.
9768 else
9772 -- If prefix is an access type, the node will be transformed into an
9773 -- explicit dereference during expansion. The type of the node is the
9774 -- designated type of that of the prefix.
9779 else
9783 -- Set flag for expander if discriminant check required
9790 and then not Init_Component
9791 then
9799 -- If the prefix is a record conversion, this may be a renamed
9800 -- discriminant whose bounds differ from those of the original
9801 -- one, so we must ensure that a range check is performed.
9806 then
9810 -- Note: No Eval processing is required, because the prefix is of a
9811 -- record type, or protected type, and neither can possibly be static.
9813 -- If the record type is atomic, and the component is non-atomic, then
9814 -- this is worth a warning, since we have a situation where the access
9815 -- to the component may cause extra read/writes of the atomic array
9816 -- object, or partial word accesses, both of which may be unexpected.
9822 then
9823 Error_Msg_N
9826 Error_Msg_N
9834 -------------------
9835 -- Resolve_Shift --
9836 -------------------
9843 begin
9844 -- We do the resolution using the base type, because intermediate values
9845 -- in expressions always are of the base type, not a subtype of it.
9858 ---------------------------
9859 -- Resolve_Short_Circuit --
9860 ---------------------------
9867 begin
9868 -- Ensure all actions associated with the left operand (e.g.
9869 -- finalization of transient controlled objects) are fully evaluated
9870 -- locally within an expression with actions. This is particularly
9871 -- helpful for coverage analysis. However this should not happen in
9872 -- generics.
9875 declare
9877 begin
9885 -- Set Comes_From_Source on L to preserve warnings for unset
9886 -- reference.
9895 -- Check for issuing warning for always False assert/check, this happens
9896 -- when assertions are turned off, in which case the pragma Assert/Check
9897 -- was transformed into:
9899 -- if False and then <condition> then ...
9901 -- and we detect this pattern
9903 if Warn_On_Assertion_Failure
9910 then
9911 declare
9914 begin
9915 -- Special handling of Asssert pragma
9919 then
9920 declare
9922 Original_Node
9923 (Expression
9926 begin
9927 -- Don't warn if original condition is explicit False,
9928 -- since obviously the failure is expected in this case.
9932 then
9935 -- Issue warning. We do not want the deletion of the
9936 -- IF/AND-THEN to take this message with it. We achieve this
9937 -- by making sure that the expanded code points to the Sloc
9938 -- of the expression, not the original pragma.
9940 else
9941 -- Note: Use Error_Msg_F here rather than Error_Msg_N.
9942 -- The source location of the expression is not usually
9943 -- the best choice here. For example, it gets located on
9944 -- the last AND keyword in a chain of boolean expressiond
9945 -- AND'ed together. It is best to put the message on the
9946 -- first character of the assertion, which is the effect
9947 -- of the First_Node call here.
9949 Error_Msg_F
9951 Expression
9956 -- Similar processing for Check pragma
9960 then
9961 -- Don't want to warn if original condition is explicit False
9963 declare
9965 Original_Node
9966 (Expression
9968 begin
9971 then
9974 -- Post warning
9976 else
9977 -- Again use Error_Msg_F rather than Error_Msg_N, see
9978 -- comment above for an explanation of why we do this.
9980 Error_Msg_F
9982 Expression
9990 -- Continue with processing of short circuit
9999 -------------------
10000 -- Resolve_Slice --
10001 -------------------
10010 begin
10013 -- Use the context type to select the prefix that yields the correct
10014 -- array type.
10016 declare
10023 begin
10031 then
10039 else
10044 else
10055 else
10065 -- If the prefix is an access to an unconstrained array, we must use
10066 -- the actual subtype of the object to perform the index checks. The
10067 -- object denoted by the prefix is implicit in the node, so we build
10068 -- an explicit representation for it in order to compute the actual
10069 -- subtype.
10074 declare
10078 begin
10089 then
10092 -- If the name is a selected component that depends on discriminants,
10093 -- build an actual subtype for it. This can happen only when the name
10094 -- itself is overloaded; otherwise the actual subtype is created when
10095 -- the selected component is analyzed.
10098 and then Full_Analysis
10100 then
10101 declare
10104 begin
10109 -- Maybe this should just be "else", instead of checking for the
10110 -- specific case of slice??? This is needed for the case where the
10111 -- prefix is an Image attribute, which gets expanded to a slice, and so
10112 -- has a constrained subtype which we want to use for the slice range
10113 -- check applied below (the range check won't get done if the
10114 -- unconstrained subtype of the 'Image is used).
10120 -- Obtain the type of the array index
10124 else
10128 -- If name was overloaded, set slice type correctly now
10132 -- Handle the generation of a range check that compares the array index
10133 -- against the discrete_range. The check is not applied to internally
10134 -- built nodes associated with the expansion of dispatch tables. Check
10135 -- that Ada.Tags has already been loaded to avoid extra dependencies on
10136 -- the unit.
10138 if Tagged_Type_Expansion
10144 then
10147 -- The discrete_range is specified by a subtype indication. Create a
10148 -- shallow copy and inherit the type, parent and source location from
10149 -- the discrete_range. This ensures that the range check is inserted
10150 -- relative to the slice and that the runtime exception points to the
10151 -- proper construct.
10160 -- The discrete_range is a regular range. Resolve the bounds and remove
10161 -- their side effects.
10163 else
10180 -- Check bad use of type with predicates
10182 declare
10185 begin
10188 then
10190 else
10195 Bad_Predicated_Subtype_Use
10200 -- Otherwise here is where we check suspicious indexes
10211 ----------------------------
10212 -- Resolve_String_Literal --
10213 ----------------------------
10224 begin
10225 -- For a string appearing in a concatenation, defer creation of the
10226 -- string_literal_subtype until the end of the resolution of the
10227 -- concatenation, because the literal may be constant-folded away. This
10228 -- is a useful optimization for long concatenation expressions.
10230 -- If the string is an aggregate built for a single character (which
10231 -- happens in a non-static context) or a is null string to which special
10232 -- checks may apply, we build the subtype. Wide strings must also get a
10233 -- string subtype if they come from a one character aggregate. Strings
10234 -- generated by attributes might be static, but it is often hard to
10235 -- determine whether the enclosing context is static, so we generate
10236 -- subtypes for them as well, thus losing some rarer optimizations ???
10237 -- Same for strings that come from a static conversion.
10239 Need_Check :=
10248 -- If the resolving type is itself a string literal subtype, we can just
10249 -- reuse it, since there is no point in creating another.
10255 and then not Need_Check
10257 N_Attribute_Reference,
10258 N_Qualified_Expression,
10259 N_Type_Conversion)
10260 then
10263 -- Do not generate a string literal subtype for the default expression
10264 -- of a formal parameter in GNATprove mode. This is because the string
10265 -- subtype is associated with the freezing actions of the subprogram,
10266 -- however freezing is disabled in GNATprove mode and as a result the
10267 -- subtype is unavailable.
10269 elsif GNATprove_Mode
10271 then
10274 -- Otherwise we must create a string literal subtype. Note that the
10275 -- whole idea of string literal subtypes is simply to avoid the need
10276 -- for building a full fledged array subtype for each literal.
10278 else
10284 or else Need_Check
10285 then
10292 then
10298 -- The validity of a null string has been checked in the call to
10299 -- Eval_String_Literal.
10304 -- Always accept string literal with component type Any_Character, which
10305 -- occurs in error situations and in comparisons of literals, both of
10306 -- which should accept all literals.
10311 -- If the type is bit-packed, then we always transform the string
10312 -- literal into a full fledged aggregate.
10317 -- Deal with cases of Wide_Wide_String, Wide_String, and String
10319 else
10320 -- For Standard.Wide_Wide_String, or any other type whose component
10321 -- type is Standard.Wide_Wide_Character, we know that all the
10322 -- characters in the string must be acceptable, since the parser
10323 -- accepted the characters as valid character literals.
10328 -- For the case of Standard.String, or any other type whose component
10329 -- type is Standard.Character, we must make sure that there are no
10330 -- wide characters in the string, i.e. that it is entirely composed
10331 -- of characters in range of type Character.
10333 -- If the string literal is the result of a static concatenation, the
10334 -- test has already been performed on the components, and need not be
10335 -- repeated.
10339 then
10343 -- If we are out of range, post error. This is one of the
10344 -- very few places that we place the flag in the middle of
10345 -- a token, right under the offending wide character. Not
10346 -- quite clear if this is right wrt wide character encoding
10347 -- sequences, but it's only an error message.
10349 Error_Msg
10356 -- For the case of Standard.Wide_String, or any other type whose
10357 -- component type is Standard.Wide_Character, we must make sure that
10358 -- there are no wide characters in the string, i.e. that it is
10359 -- entirely composed of characters in range of type Wide_Character.
10361 -- If the string literal is the result of a static concatenation,
10362 -- the test has already been performed on the components, and need
10363 -- not be repeated.
10367 then
10371 -- If we are out of range, post error. This is one of the
10372 -- very few places that we place the flag in the middle of
10373 -- a token, right under the offending wide character.
10375 -- This is not quite right, because characters in general
10376 -- will take more than one character position ???
10378 Error_Msg
10385 -- If the root type is not a standard character, then we will convert
10386 -- the string into an aggregate and will let the aggregate code do
10387 -- the checking. Standard Wide_Wide_Character is also OK here.
10389 else
10393 -- See if the component type of the array corresponding to the string
10394 -- has compile time known bounds. If yes we can directly check
10395 -- whether the evaluation of the string will raise constraint error.
10396 -- Otherwise we need to transform the string literal into the
10397 -- corresponding character aggregate and let the aggregate code do
10398 -- the checking.
10402 -- Check for the case of full range, where we are definitely OK
10408 -- Here the range is not the complete base type range, so check
10410 declare
10418 begin
10421 then
10427 then
10428 Apply_Compile_Time_Constraint_Error
10430 CE_Range_Check_Failed,
10441 -- If we got here we meed to transform the string literal into the
10442 -- equivalent qualified positional array aggregate. This is rather
10443 -- heavy artillery for this situation, but it is hard work to avoid.
10445 declare
10450 begin
10451 -- Build the character literals, we give them source locations that
10452 -- correspond to the string positions, which is a bit tricky given
10453 -- the possible presence of wide character escape sequences.
10467 -- Should we have a call to Skip_Wide here ???
10469 -- ??? else
10470 -- Skip_Wide (P);
10478 Expression =>
10485 -----------------------------
10486 -- Resolve_Type_Conversion --
10487 -----------------------------
10499 -- Set to False to suppress cases where we want to suppress the test
10500 -- for redundancy to avoid possible false positives on this warning.
10502 begin
10503 if not Conv_OK
10505 then
10509 -- If the Operand Etype is Universal_Fixed, then the conversion is
10510 -- never redundant. We need this check because by the time we have
10511 -- finished the rather complex transformation, the conversion looks
10512 -- redundant when it is not.
10517 -- If the operand is marked as Any_Fixed, then special processing is
10518 -- required. This is also a case where we suppress the test for a
10519 -- redundant conversion, since most certainly it is not redundant.
10524 -- Mixed-mode operation involving a literal. Context must be a fixed
10525 -- type which is applied to the literal subsequently.
10533 or else
10535 then
10536 -- Return if expression is ambiguous
10541 -- If nothing else, the available fixed type is Duration
10543 else
10547 -- Resolve the real operand with largest available precision
10551 else
10557 -- If the operand is a literal (it could be a non-static and
10558 -- illegal exponentiation) check whether the use of Duration
10559 -- is potentially inaccurate.
10564 then
10565 Error_Msg_N
10568 Error_Msg_N
10575 then
10578 else
10587 -- In SPARK, a type conversion between array types should be restricted
10588 -- to types which have matching static bounds.
10590 -- Protect call to Matching_Static_Array_Bounds to avoid costly
10591 -- operation if not needed.
10598 then
10599 Check_SPARK_05_Restriction
10603 -- In formal mode, the operand of an ancestor type conversion must be an
10604 -- object (not an expression).
10612 then
10618 -- Note: we do the Eval_Type_Conversion call before applying the
10619 -- required checks for a subtype conversion. This is important, since
10620 -- both are prepared under certain circumstances to change the type
10621 -- conversion to a constraint error node, but in the case of
10622 -- Eval_Type_Conversion this may reflect an illegality in the static
10623 -- case, and we would miss the illegality (getting only a warning
10624 -- message), if we applied the type conversion checks first.
10628 -- Even when evaluation is not possible, we may be able to simplify the
10629 -- conversion or its expression. This needs to be done before applying
10630 -- checks, since otherwise the checks may use the original expression
10631 -- and defeat the simplifications. This is specifically the case for
10632 -- elimination of the floating-point Truncation attribute in
10633 -- float-to-int conversions.
10637 -- If after evaluation we still have a type conversion, then we may need
10638 -- to apply checks required for a subtype conversion.
10640 -- Skip these type conversion checks if universal fixed operands
10641 -- operands involved, since range checks are handled separately for
10642 -- these cases (in the appropriate Expand routines in unit Exp_Fixd).
10648 then
10652 -- Issue warning for conversion of simple object to its own type. We
10653 -- have to test the original nodes, since they may have been rewritten
10654 -- by various optimizations.
10658 -- Here we test for a redundant conversion if the warning mode is
10659 -- active (and was not locally reset), and we have a type conversion
10660 -- from source not appearing in a generic instance.
10662 if Test_Redundant
10665 and then not In_Instance
10666 then
10670 -- If the node is part of a larger expression, the Target_Type
10671 -- may not be the original type of the node if the context is a
10672 -- condition. Recover original type to see if conversion is needed.
10676 then
10680 -- If we have an entity name, then give the warning if the entity
10681 -- is the right type, or if it is a loop parameter covered by the
10682 -- original type (that's needed because loop parameters have an
10683 -- odd subtype coming from the bounds).
10686 and then
10688 or else
10692 -- If not an entity, then type of expression must match
10695 then
10696 -- One more check, do not give warning if the analyzed conversion
10697 -- has an expression with non-static bounds, and the bounds of the
10698 -- target are static. This avoids junk warnings in cases where the
10699 -- conversion is necessary to establish staticness, for example in
10700 -- a case statement.
10704 then
10707 -- Finally, if this type conversion occurs in a context requiring
10708 -- a prefix, and the expression is a qualified expression then the
10709 -- type conversion is not redundant, since a qualified expression
10710 -- is not a prefix, whereas a type conversion is. For example, "X
10711 -- := T'(Funx(...)).Y;" is illegal because a selected component
10712 -- requires a prefix, but a type conversion makes it legal: "X :=
10713 -- T(T'(Funx(...))).Y;"
10715 -- In Ada 2012, a qualified expression is a name, so this idiom is
10716 -- no longer needed, but we still suppress the warning because it
10717 -- seems unfriendly for warnings to pop up when you switch to the
10718 -- newer language version.
10722 N_Indexed_Component,
10723 N_Selected_Component,
10724 N_Slice,
10725 N_Explicit_Dereference)
10726 then
10729 -- Never warn on conversion to Long_Long_Integer'Base since
10730 -- that is most likely an artifact of the extended overflow
10731 -- checking and comes from complex expanded code.
10736 -- Here we give the redundant conversion warning. If it is an
10737 -- entity, give the name of the entity in the message. If not,
10738 -- just mention the expression.
10740 -- Shoudn't we test Warn_On_Redundant_Constructs here ???
10742 else
10745 Error_Msg_NE -- CODEFIX
10748 else
10749 Error_Msg_NE
10757 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
10758 -- No need to perform any interface conversion if the type of the
10759 -- expression coincides with the target type.
10762 and then Expander_Active
10764 then
10765 declare
10769 begin
10770 -- If the type of the operand is a limited view, use nonlimited
10771 -- view when available. If it is a class-wide type, recover the
10772 -- class-wide type of the nonlimited view.
10776 then
10792 -- Conversion from interface type
10796 -- Ada 2005 (AI-217): Handle entities from limited views
10800 Error_Msg_NE -- CODEFIX
10803 Error_Msg_N
10805 N);
10808 and then not
10811 then
10813 Error_Msg_NE -- CODEFIX
10816 Error_Msg_N
10818 N);
10820 else
10824 -- Conversion to interface type
10828 -- Handle subtypes
10835 or else Interface_Present_In_Ancestor
10838 then
10840 else
10843 Error_Msg_N
10851 -- Ada 2012: if target type has predicates, the result requires a
10852 -- predicate check. If the context is a call to another predicate
10853 -- check we must prevent infinite recursion.
10859 or else
10861 then
10864 else
10869 -- If at this stage we have a real to integer conversion, make sure
10870 -- that the Do_Range_Check flag is set, because such conversions in
10871 -- general need a range check. We only need this if expansion is off
10872 -- or we are in GNATProve mode.
10878 then
10883 ----------------------
10884 -- Resolve_Unary_Op --
10885 ----------------------
10894 begin
10897 Check_SPARK_05_Restriction
10901 -- Deal with intrinsic unary operators
10907 then
10912 -- Deal with universal cases
10915 or else
10917 then
10924 -- Generate warning for expressions like abs (x mod 2)
10926 if Warn_On_Redundant_Constructs
10928 then
10932 Error_Msg_N -- CODEFIX
10937 -- Deal with reference generation
10944 -- Set overflow checking bit. Much cleverer code needed here eventually
10945 -- and perhaps the Resolve routines should be separated for the various
10946 -- arithmetic operations, since they will need different processing ???
10954 -- Generate warning for expressions like -5 mod 3 for integers. No need
10955 -- to worry in the floating-point case, since parens do not affect the
10956 -- result so there is no point in giving in a warning.
10958 declare
10967 begin
10968 if Warn_On_Questionable_Missing_Parens
10972 then
10975 -- We are looking for cases where the right operand is not
10976 -- parenthesized, and is a binary operator, multiply, divide, or
10977 -- mod. These are the cases where the grouping can affect results.
10981 then
10982 -- For mod, we always give the warning, since the value is
10983 -- affected by the parenthesization (e.g. (-5) mod 315 /=
10984 -- -(5 mod 315)). But for the other cases, the only concern is
10985 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
10986 -- overflows, but (-2) * 64 does not). So we try to give the
10987 -- message only when overflow is possible.
10991 then
10996 else
11002 else
11006 -- Note that the test below is deliberately excluding the
11007 -- largest negative number, since that is a potentially
11008 -- troublesome case (e.g. -2 * x, where the result is the
11009 -- largest negative integer has an overflow with 2 * x).
11016 -- For the multiplication case, the only case we have to worry
11017 -- about is when (-a)*b is exactly the largest negative number
11018 -- so that -(a*b) can cause overflow. This can only happen if
11019 -- a is a power of 2, and more generally if any operand is a
11020 -- constant that is not a power of 2, then the parentheses
11021 -- cannot affect whether overflow occurs. We only bother to
11022 -- test the left most operand
11024 -- Loop looking at left operands for one that has known value
11031 -- Operand value of 0 or 1 skips warning
11036 -- Otherwise check power of 2, if power of 2, warn, if
11037 -- anything else, skip warning.
11039 else
11043 else
11052 -- Keep looking at left operands
11057 -- For rem or "/" we can only have a problematic situation
11058 -- if the divisor has a value of minus one or one. Otherwise
11059 -- overflow is impossible (divisor > 1) or we have a case of
11060 -- division by zero in any case.
11065 then
11069 -- If we fall through warning should be issued
11071 -- Shouldn't we test Warn_On_Questionable_Missing_Parens ???
11073 Error_Msg_N
11080 ----------------------------------
11081 -- Resolve_Unchecked_Expression --
11082 ----------------------------------
11084 procedure Resolve_Unchecked_Expression
11087 is
11088 begin
11093 ---------------------------------------
11094 -- Resolve_Unchecked_Type_Conversion --
11095 ---------------------------------------
11097 procedure Resolve_Unchecked_Type_Conversion
11100 is
11106 begin
11107 -- Resolve operand using its own type
11111 -- In an inlined context, the unchecked conversion may be applied
11112 -- to a literal, in which case its type is the type of the context.
11113 -- (In other contexts conversions cannot apply to literals).
11115 if In_Inlined_Body
11119 then
11127 ------------------------------
11128 -- Rewrite_Operator_As_Call --
11129 ------------------------------
11136 begin
11143 New_N :=
11154 ------------------------------
11155 -- Rewrite_Renamed_Operator --
11156 ------------------------------
11158 procedure Rewrite_Renamed_Operator
11162 is
11167 begin
11168 -- Do not perform this transformation within a pre/postcondition,
11169 -- because the expression will be re-analyzed, and the transformation
11170 -- might affect the visibility of the operator, e.g. in an instance.
11176 -- Rewrite the operator node using the real operator, not its renaming.
11177 -- Exclude user-defined intrinsic operations of the same name, which are
11178 -- treated separately and rewritten as calls.
11187 -- Indicate that both the original entity and its renaming are
11188 -- referenced at this point.
11199 -- If the context type is private, add the appropriate conversions so
11200 -- that the operator is applied to the full view. This is done in the
11201 -- routines that resolve intrinsic operators.
11205 then
11207 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
11208 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
11221 -- Operator renames a user-defined operator of the same name. Use the
11222 -- original operator in the node, which is the one Gigi knows about.
11229 -----------------------
11230 -- Set_Slice_Subtype --
11231 -----------------------
11233 -- Build an implicit subtype declaration to represent the type delivered by
11234 -- the slice. This is an abbreviated version of an array subtype. We define
11235 -- an index subtype for the slice, using either the subtype name or the
11236 -- discrete range of the slice. To be consistent with index usage elsewhere
11237 -- we create a list header to hold the single index. This list is not
11238 -- otherwise attached to the syntax tree.
11249 begin
11255 else
11256 -- We force the evaluation of a range. This is definitely needed in
11257 -- the renamed case, and seems safer to do unconditionally. Note in
11258 -- any case that since we will create and insert an Itype referring
11259 -- to this range, we must make sure any side effect removal actions
11260 -- are inserted before the Itype definition.
11266 -- If the discrete range is given by a subtype indication, the
11267 -- type of the slice is the base of the subtype mark.
11270 declare
11272 begin
11281 -- Take a new copy of Drange (where bounds have been rewritten to
11282 -- reference side-effect-free names). Using a separate tree ensures
11283 -- that further expansion (e.g. while rewriting a slice assignment
11284 -- into a FOR loop) does not attempt to remove side effects on the
11285 -- bounds again (which would cause the bounds in the index subtype
11286 -- definition to refer to temporaries before they are defined) (the
11287 -- reason is that some names are considered side effect free here
11288 -- for the subtype, but not in the context of a loop iteration
11289 -- scheme).
11310 -- The Etype of the existing Slice node is reset to this slice subtype.
11311 -- Its bounds are obtained from its first index.
11315 -- For packed slice subtypes, freeze immediately (except in the case of
11316 -- being in a "spec expression" where we never freeze when we first see
11317 -- the expression).
11322 -- For all other cases insert an itype reference in the slice's actions
11323 -- so that the itype is frozen at the proper place in the tree (i.e. at
11324 -- the point where actions for the slice are analyzed). Note that this
11325 -- is different from freezing the itype immediately, which might be
11326 -- premature (e.g. if the slice is within a transient scope). This needs
11327 -- to be done only if expansion is enabled.
11334 --------------------------------
11335 -- Set_String_Literal_Subtype --
11336 --------------------------------
11344 begin
11356 -- The low bound is set from the low bound of the corresponding index
11357 -- type. Note that we do not store the high bound in the string literal
11358 -- subtype, but it can be deduced if necessary from the length and the
11359 -- low bound.
11364 -- If the lower bound is not static we create a range for the string
11365 -- literal, using the index type and the known length of the literal.
11366 -- The index type is not necessarily Positive, so the upper bound is
11367 -- computed as T'Val (T'Pos (Low_Bound) + L - 1).
11369 else
11370 declare
11376 Prefix =>
11380 Left_Opnd =>
11383 Prefix =>
11385 Expressions =>
11387 Right_Opnd =>
11396 begin
11398 Set_String_Literal_Low_Bound
11401 else
11402 -- If the index type is an enumeration type, build bounds
11403 -- expression with attributes.
11405 Set_String_Literal_Low_Bound
11409 Prefix =>
11416 -- Build bona fide subtype for the string, and wrap it in an
11417 -- unchecked conversion, because the backend expects the
11418 -- String_Literal_Subtype to have a static lower bound.
11420 Index_Subtype :=
11427 -- In the context, the Index_Type may already have a constraint,
11428 -- so use common base type on string subtype. The base type may
11429 -- be used when generating attributes of the string, for example
11430 -- in the context of a slice assignment.
11455 ------------------------------
11456 -- Simplify_Type_Conversion --
11457 ------------------------------
11460 begin
11462 declare
11467 begin
11468 -- Special processing if the conversion is the expression of a
11469 -- Rounding or Truncation attribute reference. In this case we
11470 -- replace:
11472 -- ityp (ftyp'Rounding (x)) or ityp (ftyp'Truncation (x))
11474 -- by
11476 -- ityp (x)
11478 -- with the Float_Truncate flag set to False or True respectively,
11479 -- which is more efficient.
11482 and then
11488 Name_Truncation)
11489 then
11490 declare
11493 begin
11503 -----------------------------
11504 -- Unique_Fixed_Point_Type --
11505 -----------------------------
11514 -- Give error messages for true ambiguity. Messages are posted on node
11515 -- N, and entities T1, T2 are the possible interpretations.
11517 -----------------------
11518 -- Fixed_Point_Error --
11519 -----------------------
11522 begin
11528 -- Start of processing for Unique_Fixed_Point_Type
11530 begin
11531 -- The operations on Duration are visible, so Duration is always a
11532 -- possible interpretation.
11536 -- Look for fixed-point types in enclosing scopes
11545 then
11547 Fixed_Point_Error;
11549 else
11560 -- Look for visible fixed type declarations in the context
11571 then
11573 Fixed_Point_Error;
11575 else
11588 Error_Msg_NE
11590 else
11591 Error_Msg_NE
11598 ----------------------
11599 -- Valid_Conversion --
11600 ----------------------
11602 function Valid_Conversion
11607 is
11612 function Conversion_Check
11615 -- Little routine to post Msg if Valid is False, returns Valid value
11618 -- If Report_Errs, then calls Errout.Error_Msg_N with its arguments
11620 procedure Conversion_Error_NE
11624 -- If Report_Errs, then calls Errout.Error_Msg_NE with its arguments
11626 function Valid_Tagged_Conversion
11629 -- Specifically test for validity of tagged conversions
11632 -- Check index and component conformance, and accessibility levels if
11633 -- the component types are anonymous access types (Ada 2005).
11635 ----------------------
11636 -- Conversion_Check --
11637 ----------------------
11639 function Conversion_Check
11642 is
11643 begin
11644 if not Valid
11646 -- A generic unit has already been analyzed and we have verified
11647 -- that a particular conversion is OK in that context. Since the
11648 -- instance is reanalyzed without relying on the relationships
11649 -- established during the analysis of the generic, it is possible
11650 -- to end up with inconsistent views of private types. Do not emit
11651 -- the error message in such cases. The rest of the machinery in
11652 -- Valid_Conversion still ensures the proper compatibility of
11653 -- target and operand types.
11655 and then not In_Instance
11656 then
11663 ------------------------
11664 -- Conversion_Error_N --
11665 ------------------------
11668 begin
11674 -------------------------
11675 -- Conversion_Error_NE --
11676 -------------------------
11678 procedure Conversion_Error_NE
11682 is
11683 begin
11689 ----------------------------
11690 -- Valid_Array_Conversion --
11691 ----------------------------
11694 is
11709 begin
11710 -- Error if wrong number of dimensions
11712 if
11714 then
11715 Conversion_Error_N
11719 -- Number of dimensions matches
11721 else
11722 -- Loop through indexes of the two arrays
11730 -- Error if index types are incompatible
11736 then
11737 Conversion_Error_N
11739 Operand);
11747 -- If component types have same base type, all set
11752 -- Here if base types of components are not the same. The only
11753 -- time this is allowed is if we have anonymous access types.
11755 -- The conversion of arrays of anonymous access types can lead
11756 -- to dangling pointers. AI-392 formalizes the accessibility
11757 -- checks that must be applied to such conversions to prevent
11758 -- out-of-scope references.
11760 elsif Ekind_In
11762 E_Anonymous_Access_Subprogram_Type)
11764 and then
11766 then
11769 then
11772 Conversion_Error_N
11782 -- Conversion not allowed because of accessibility levels
11784 else
11785 Conversion_Error_N
11791 else
11795 -- All other cases where component base types do not match
11797 else
11798 Conversion_Error_N
11800 Operand);
11804 -- Check that component subtypes statically match. For numeric
11805 -- types this means that both must be either constrained or
11806 -- unconstrained. For enumeration types the bounds must match.
11807 -- All of this is checked in Subtypes_Statically_Match.
11809 if not Subtypes_Statically_Match
11811 then
11812 Conversion_Error_N
11821 -----------------------------
11822 -- Valid_Tagged_Conversion --
11823 -----------------------------
11825 function Valid_Tagged_Conversion
11828 is
11829 begin
11830 -- Upward conversions are allowed (RM 4.6(22))
11834 then
11837 -- Downward conversion are allowed if the operand is class-wide
11838 -- (RM 4.6(23)).
11842 then
11847 then
11848 return
11852 -- Ada 2005 (AI-251): The conversion to/from interface types is
11853 -- always valid
11858 -- If the operand is a class-wide type obtained through a limited_
11859 -- with clause, and the context includes the nonlimited view, use
11860 -- it to determine whether the conversion is legal.
11866 then
11871 then
11874 else
11875 Conversion_Error_NE
11882 -- Start of processing for Valid_Conversion
11884 begin
11888 declare
11896 begin
11897 -- Remove procedure calls, which syntactically cannot appear in
11898 -- this context, but which cannot be removed by type checking,
11899 -- because the context does not impose a type.
11901 -- The node may be labelled overloaded, but still contain only one
11902 -- interpretation because others were discarded earlier. If this
11903 -- is the case, retain the single interpretation if legal.
11911 then
11912 -- More than one candidate interpretation is available
11920 -- When compiling for a system where Address is of a visible
11921 -- integer type, spurious ambiguities can be produced when
11922 -- arithmetic operations have a literal operand and return
11923 -- System.Address or a descendant of it. These ambiguities
11924 -- are usually resolved by the context, but for conversions
11925 -- there is no context type and the removal of the spurious
11926 -- operations must be done explicitly here.
11928 if not Address_Is_Private
11930 then
11955 Conversion_Error_N
11958 -- If the interpretation involves a standard operator, use
11959 -- the location of the type, which may be user-defined.
11963 else
11967 Conversion_Error_N -- CODEFIX
11972 else
11976 Conversion_Error_N -- CODEFIX
11988 -- Deal with conversion of integer type to address if the pragma
11989 -- Allow_Integer_Address is in effect. We convert the conversion to
11990 -- an unchecked conversion in this case and we are all done.
11998 -- If we are within a child unit, check whether the type of the
11999 -- expression has an ancestor in a parent unit, in which case it
12000 -- belongs to its derivation class even if the ancestor is private.
12001 -- See RM 7.3.1 (5.2/3).
12005 -- Numeric types
12009 -- A universal fixed expression can be converted to any numeric type
12014 -- Also no need to check when in an instance or inlined body, because
12015 -- the legality has been established when the template was analyzed.
12016 -- Furthermore, numeric conversions may occur where only a private
12017 -- view of the operand type is visible at the instantiation point.
12018 -- This results in a spurious error if we check that the operand type
12019 -- is a numeric type.
12021 -- Note: in a previous version of this unit, the following tests were
12022 -- applied only for generated code (Comes_From_Source set to False),
12023 -- but in fact the test is required for source code as well, since
12024 -- this situation can arise in source code.
12029 -- Otherwise we need the conversion check
12031 else
12032 return Conversion_Check
12034 or else
12040 -- Array types
12046 then
12047 Conversion_Error_N
12051 else
12055 -- Ada 2005 (AI-251): Internally generated conversions of access to
12056 -- interface types added to force the displacement of the pointer to
12057 -- reference the corresponding dispatch table.
12062 then
12065 -- Ada 2005 (AI-251): Anonymous access types where target references an
12066 -- interface type.
12070 E_Anonymous_Access_Type)
12072 then
12073 -- Check the static accessibility rule of 4.6(17). Note that the
12074 -- check is not enforced when within an instance body, since the
12075 -- RM requires such cases to be caught at run time.
12077 -- If the operand is a rewriting of an allocator no check is needed
12078 -- because there are no accessibility issues.
12086 then
12087 -- In an instance, this is a run-time check, but one we know
12088 -- will fail, so generate an appropriate warning. The raise
12089 -- will be generated by Expand_N_Type_Conversion.
12093 Conversion_Error_N
12095 Operand);
12098 else
12099 Conversion_Error_N
12101 Operand);
12105 -- Special accessibility checks are needed in the case of access
12106 -- discriminants declared for a limited type.
12110 then
12111 -- When the operand is a selected access discriminant the check
12112 -- needs to be made against the level of the object denoted by
12113 -- the prefix of the selected name (Object_Access_Level handles
12114 -- checking the prefix of the operand for this case).
12119 then
12120 -- In an instance, this is a run-time check, but one we know
12121 -- will fail, so generate an appropriate warning. The raise
12122 -- will be generated by Expand_N_Type_Conversion.
12126 Conversion_Error_N
12131 -- Real error if not in instance body
12133 else
12134 Conversion_Error_N
12141 -- The case of a reference to an access discriminant from
12142 -- within a limited type declaration (which will appear as
12143 -- a discriminal) is always illegal because the level of the
12144 -- discriminant is considered to be deeper than any (nameable)
12145 -- access type.
12149 and then
12152 then
12153 Conversion_Error_N
12155 Operand);
12163 -- General and anonymous access types
12166 E_Anonymous_Access_Type)
12167 and then
12168 Conversion_Check
12170 and then not
12172 E_Access_Protected_Subprogram_Type),
12174 then
12177 then
12178 Conversion_Error_N
12183 -- Check the static accessibility rule of 4.6(17). Note that the
12184 -- check is not enforced when within an instance body, since the RM
12185 -- requires such cases to be caught at run time.
12190 N_Object_Declaration
12191 then
12192 -- Ada 2012 (AI05-0149): Perform legality checking on implicit
12193 -- conversions from an anonymous access type to a named general
12194 -- access type. Such conversions are not allowed in the case of
12195 -- access parameters and stand-alone objects of an anonymous
12196 -- access type. The implicit conversion case is recognized by
12197 -- testing that Comes_From_Source is False and that it's been
12198 -- rewritten. The Comes_From_Source test isn't sufficient because
12199 -- nodes in inlined calls to predefined library routines can have
12200 -- Comes_From_Source set to False. (Is there a better way to test
12201 -- for implicit conversions???)
12208 then
12211 -- Implicit conversions aren't allowed for objects of an
12212 -- anonymous access type, since such objects have nonstatic
12213 -- levels in Ada 2012.
12216 N_Object_Declaration
12217 then
12218 Conversion_Error_N
12223 -- Implicit conversions aren't allowed for anonymous access
12224 -- parameters. The "not Is_Local_Anonymous_Access_Type" test
12225 -- is done to exclude anonymous access results.
12229 N_Function_Specification,
12230 N_Procedure_Specification)
12231 then
12232 Conversion_Error_N
12237 -- This is a case where there's an enclosing object whose
12238 -- to which the "statically deeper than" relationship does
12239 -- not apply (such as an access discriminant selected from
12240 -- a dereference of an access parameter).
12244 then
12245 Conversion_Error_N
12250 -- In other cases, the level of the operand's type must be
12251 -- statically less deep than that of the target type, else
12252 -- implicit conversion is disallowed (by RM12-8.6(27.1/3)).
12256 then
12257 Conversion_Error_N
12266 then
12267 -- In an instance, this is a run-time check, but one we know
12268 -- will fail, so generate an appropriate warning. The raise
12269 -- will be generated by Expand_N_Type_Conversion.
12273 Conversion_Error_N
12275 Operand);
12278 -- If not in an instance body, this is a real error
12280 else
12281 -- Avoid generation of spurious error message
12284 Conversion_Error_N
12286 Operand);
12292 -- Special accessibility checks are needed in the case of access
12293 -- discriminants declared for a limited type.
12297 then
12298 -- When the operand is a selected access discriminant the check
12299 -- needs to be made against the level of the object denoted by
12300 -- the prefix of the selected name (Object_Access_Level handles
12301 -- checking the prefix of the operand for this case).
12306 then
12307 -- In an instance, this is a run-time check, but one we know
12308 -- will fail, so generate an appropriate warning. The raise
12309 -- will be generated by Expand_N_Type_Conversion.
12313 Conversion_Error_N
12318 -- If not in an instance body, this is a real error
12320 else
12321 Conversion_Error_N
12328 -- The case of a reference to an access discriminant from
12329 -- within a limited type declaration (which will appear as
12330 -- a discriminal) is always illegal because the level of the
12331 -- discriminant is considered to be deeper than any (nameable)
12332 -- access type.
12335 and then
12338 then
12339 Conversion_Error_N
12341 Operand);
12347 -- In the presence of limited_with clauses we have to use nonlimited
12348 -- views, if available.
12352 -- Helper function to handle limited views
12354 --------------------------
12355 -- Full_Designated_Type --
12356 --------------------------
12361 begin
12362 -- Handle the limited view of a type
12366 then
12368 else
12373 -- Local Declarations
12381 -- Start of processing for Check_Limited
12383 begin
12387 else
12389 Conversion_Error_NE
12394 -- Ada 2005 AI-384: legality rule is symmetric in both
12395 -- designated types. The conversion is legal (with possible
12396 -- constraint check) if either designated type is
12397 -- unconstrained.
12400 or else
12402 and then
12405 then
12406 -- Special case, if Value_Size has been used to make the
12407 -- sizes different, the conversion is not allowed even
12408 -- though the subtypes statically match.
12413 then
12414 Conversion_Error_NE
12417 Conversion_Error_NE
12422 -- Normal case where conversion is allowed
12424 else
12428 else
12429 Error_Msg_NE
12437 -- Access to subprogram types. If the operand is an access parameter,
12438 -- the type has a deeper accessibility that any master, and cannot be
12439 -- assigned. We must make an exception if the conversion is part of an
12440 -- assignment and the target is the return object of an extended return
12441 -- statement, because in that case the accessibility check takes place
12442 -- after the return.
12446 -- Note: this test of Opnd_Type is there to prevent entering this
12447 -- branch in the case of a remote access to subprogram type, which
12448 -- is internally represented as an E_Record_Type.
12451 then
12455 and then
12459 then
12460 Conversion_Error_N
12462 Operand);
12463 Conversion_Error_N
12466 Operand);
12468 Error_Msg_NE
12473 -- Check that the designated types are subtype conformant
12479 -- Check the static accessibility rule of 4.6(20)
12483 then
12484 Conversion_Error_N
12486 Operand);
12488 -- Check that if the operand type is declared in a generic body,
12489 -- then the target type must be declared within that same body
12490 -- (enforces last sentence of 4.6(20)).
12493 declare
12499 begin
12506 Conversion_Error_N
12515 -- Remote access to subprogram types
12519 then
12520 -- It is valid to convert from one RAS type to another provided
12521 -- that their specification statically match.
12523 -- Note: at this point, remote access to subprogram types have been
12524 -- expanded to their E_Record_Type representation, and we need to
12525 -- go back to the original access type definition using the
12526 -- Corresponding_Remote_Type attribute in order to check that the
12527 -- designated profiles match.
12532 Check_Subtype_Conformant
12535 Old_Id =>
12537 Err_Loc =>
12538 N);
12541 -- If it was legal in the generic, it's legal in the instance
12546 -- If both are tagged types, check legality of view conversions
12549 and then
12551 then
12554 -- Types derived from the same root type are convertible
12559 -- In an instance or an inlined body, there may be inconsistent views of
12560 -- the same type, or of types derived from a common root.
12563 and then
12566 then
12569 -- Special check for common access type error case
12573 then
12575 Conversion_Error_NE -- CODEFIX
12579 -- Here we have a real conversion error
12581 else
12582 Conversion_Error_NE