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1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- S E M _ R E S --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2014, 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 ------------------------------------------------------------------------------
84 -----------------------
85 -- Local Subprograms --
86 -----------------------
88 -- Second pass (top-down) type checking and overload resolution procedures
89 -- Typ is the type required by context. These procedures propagate the type
90 -- information recursively to the descendants of N. If the node is not
91 -- overloaded, its Etype is established in the first pass. If overloaded,
92 -- the Resolve routines set the correct type. For arith. operators, the
93 -- Etype is the base type of the context.
95 -- Note that Resolve_Attribute is separated off in Sem_Attr
98 -- Enforce the restrictions on the use of discriminants when constraining
99 -- a component of a discriminated type (record or concurrent type).
102 -- Given a node for an operator associated with type T, check that
103 -- the operator is visible. Operators all of whose operands are
104 -- universal must be checked for visibility during resolution
105 -- because their type is not determinable based on their operands.
107 procedure Check_Fully_Declared_Prefix
110 -- Check that the type of the prefix of a dereference is not incomplete
113 -- Determine whether node Ghost_Ref appears within a Ghost-friendly context
114 -- where Ghost entity Ghost_Id can safely reside.
117 -- Given a call node, N, which is known to occur immediately within the
118 -- subprogram being called, determines whether it is a detectable case of
119 -- an infinite recursion, and if so, outputs appropriate messages. Returns
120 -- True if an infinite recursion is detected, and False otherwise.
123 -- If the type of the object being initialized uses the secondary stack
124 -- directly or indirectly, create a transient scope for the call to the
125 -- init proc. This is because we do not create transient scopes for the
126 -- initialization of individual components within the init proc itself.
127 -- Could be optimized away perhaps?
130 -- N is the node for a logical operator. If the operator is predefined, and
131 -- the root type of the operands is Standard.Boolean, then a check is made
132 -- for restriction No_Direct_Boolean_Operators. This procedure also handles
133 -- the style check for Style_Check_Boolean_And_Or.
136 -- N is either an indexed component or a selected component. This function
137 -- returns true if the prefix refers to an object that has an address
138 -- clause (the case in which we may want to issue a warning).
141 -- Determine whether E is an access type declared by an access declaration,
142 -- and not an (anonymous) allocator type.
145 -- Utility to check whether the entity for an operator is a predefined
146 -- operator, in which case the expression is left as an operator in the
147 -- tree (else it is rewritten into a call). An instance of an intrinsic
148 -- conversion operation may be given an operator name, but is not treated
149 -- like an operator. Note that an operator that is an imported back-end
150 -- builtin has convention Intrinsic, but is expected to be rewritten into
151 -- a call, so such an operator is not treated as predefined by this
152 -- predicate.
155 -- If a default expression in entry call N depends on the discriminants
156 -- of the task, it must be replaced with a reference to the discriminant
157 -- of the task being called.
159 procedure Resolve_Op_Concat_Arg
164 -- Internal procedure for Resolve_Op_Concat to resolve one operand of
165 -- concatenation operator. The operand is either of the array type or of
166 -- the component type. If the operand is an aggregate, and the component
167 -- type is composite, this is ambiguous if component type has aggregates.
170 -- Does the first part of the work of Resolve_Op_Concat
173 -- Does the "rest" of the work of Resolve_Op_Concat, after the left operand
174 -- has been resolved. See Resolve_Op_Concat for details.
212 function Operator_Kind
215 -- Utility to map the name of an operator into the corresponding Node. Used
216 -- by other node rewriting procedures.
219 -- Resolve actuals of call, and add default expressions for missing ones.
220 -- N is the Node_Id for the subprogram call, and Nam is the entity of the
221 -- called subprogram.
224 -- Called from Resolve_Call, when the prefix denotes an entry or element
225 -- of entry family. Actuals are resolved as for subprograms, and the node
226 -- is rebuilt as an entry call. Also called for protected operations. Typ
227 -- is the context type, which is used when the operation is a protected
228 -- function with no arguments, and the return value is indexed.
231 -- A call to a user-defined intrinsic operator is rewritten as a call to
232 -- the corresponding predefined operator, with suitable conversions. Note
233 -- that this applies only for intrinsic operators that denote predefined
234 -- operators, not ones that are intrinsic imports of back-end builtins.
237 -- Ditto, for arithmetic unary operators
240 -- If an operator node resolves to a call to a user-defined operator,
241 -- rewrite the node as a function call.
243 procedure Make_Call_Into_Operator
247 -- Inverse transformation: if an operator is given in functional notation,
248 -- then after resolving the node, transform into an operator node, so
249 -- that operands are resolved properly. Recall that predefined operators
250 -- do not have a full signature and special resolution rules apply.
252 procedure Rewrite_Renamed_Operator
256 -- An operator can rename another, e.g. in an instantiation. In that
257 -- case, the proper operator node must be constructed and resolved.
260 -- The String_Literal_Subtype is built for all strings that are not
261 -- operands of a static concatenation operation. If the argument is
262 -- not a N_String_Literal node, then the call has no effect.
265 -- Build subtype of array type, with the range specified by the slice
268 -- Called after N has been resolved and evaluated, but before range checks
269 -- have been applied. Currently simplifies a combination of floating-point
270 -- to integer conversion and Rounding or Truncation attribute.
273 -- A universal_fixed expression in an universal context is unambiguous if
274 -- there is only one applicable fixed point type. Determining whether there
275 -- is only one requires a search over all visible entities, and happens
276 -- only in very pathological cases (see 6115-006).
278 -------------------------
279 -- Ambiguous_Character --
280 -------------------------
285 begin
289 -- First the ones in Standard
294 -- Include Wide_Wide_Character in Ada 2005 mode
300 -- Now any other types that match
310 -------------------------
311 -- Analyze_And_Resolve --
312 -------------------------
315 begin
321 begin
326 -- Versions with check(s) suppressed
328 procedure Analyze_And_Resolve
332 is
335 begin
337 declare
339 begin
345 else
346 declare
348 begin
356 and then Scope_Is_Transient
357 then
358 -- This can only happen if a transient scope was created for an inner
359 -- expression, which will be removed upon completion of the analysis
360 -- of an enclosing construct. The transient scope must have the
361 -- suppress status of the enclosing environment, not of this Analyze
362 -- call.
365 Scope_Suppress;
369 procedure Analyze_And_Resolve
372 is
375 begin
377 declare
379 begin
385 else
386 declare
388 begin
397 Scope_Suppress;
401 ----------------------------
402 -- Check_Discriminant_Use --
403 ----------------------------
411 begin
412 -- Any use in a spec-expression is legal
419 -- Discriminant cannot be used to constrain a scalar type
426 then
431 -- The following check catches the unusual case where a
432 -- discriminant appears within an index constraint that is part of
433 -- a larger expression within a constraint on a component, e.g. "C
434 -- : Int range 1 .. F (new A(1 .. D))". For now we only check case
435 -- of record components, and note that a similar check should also
436 -- apply in the case of discriminant constraints below. ???
438 -- Note that the check for N_Subtype_Declaration below is to
439 -- detect the valid use of discriminants in the constraints of a
440 -- subtype declaration when this subtype declaration appears
441 -- inside the scope of a record type (which is syntactically
442 -- illegal, but which may be created as part of derived type
443 -- processing for records). See Sem_Ch3.Build_Derived_Record_Type
444 -- for more info.
448 and then not
450 and then
452 N_Subtype_Declaration)
454 then
455 Error_Msg_N
460 -- Detect a common error:
462 -- type R (D : Positive := 100) is record
463 -- Name : String (1 .. D);
464 -- end record;
466 -- The default value causes an object of type R to be allocated
467 -- with room for Positive'Last characters. The RM does not mandate
468 -- the allocation of the maximum size, but that is what GNAT does
469 -- so we should warn the programmer that there is a problem.
478 -- Return True if type T has a large enough range that any
479 -- array whose index type covered the whole range of the type
480 -- would likely raise Storage_Error.
482 ------------------------
483 -- Large_Storage_Type --
484 ------------------------
487 begin
488 -- The type is considered large if its bounds are known at
489 -- compile time and if it requires at least as many bits as
490 -- a Positive to store the possible values.
494 and then
499 -- Start of processing for Check_Large
501 begin
502 -- Check that the Disc has a large range
508 -- If the enclosing type is limited, we allocate only the
509 -- default value, not the maximum, and there is no need for
510 -- a warning.
516 -- Check that it is the high bound
520 then
524 -- Check the array allows a large range at this bound. First
525 -- find the array
539 -- Next, find the dimension
547 loop
556 -- Now, check the dimension has a large range
562 -- Warn about the danger
564 Error_Msg_N
574 -- Legal case is in index or discriminant constraint
577 N_Discriminant_Association)
578 then
580 Error_Msg_N
585 then
586 Error_Msg_N
592 -- Otherwise, context is an expression. It should not be within (i.e. a
593 -- subexpression of) a constraint for a component.
595 else
599 N_Subtype_Indication,
600 N_Entry_Declaration)
601 loop
607 -- If the discriminant is used in an expression that is a bound of a
608 -- scalar type, an Itype is created and the bounds are attached to
609 -- its range, not to the original subtype indication. Such use is of
610 -- course a double fault.
614 N_Derived_Type_Definition)
617 -- The constraint itself may be given by a subtype indication,
618 -- rather than by a more common discrete range.
621 and then
625 then
626 Error_Msg_N
632 --------------------------------
633 -- Check_For_Visible_Operator --
634 --------------------------------
637 begin
639 Error_Msg_NE -- CODEFIX
641 Error_Msg_N -- CODEFIX
646 ----------------------------------
647 -- Check_Fully_Declared_Prefix --
648 ----------------------------------
650 procedure Check_Fully_Declared_Prefix
653 is
654 begin
655 -- Check that the designated type of the prefix of a dereference is
656 -- not an incomplete type. This cannot be done unconditionally, because
657 -- dereferences of private types are legal in default expressions. This
658 -- case is taken care of in Check_Fully_Declared, called below. There
659 -- are also 2005 cases where it is legal for the prefix to be unfrozen.
661 -- This consideration also applies to similar checks for allocators,
662 -- qualified expressions, and type conversions.
664 -- An additional exception concerns other per-object expressions that
665 -- are not directly related to component declarations, in particular
666 -- representation pragmas for tasks. These will be per-object
667 -- expressions if they depend on discriminants or some global entity.
668 -- If the task has access discriminants, the designated type may be
669 -- incomplete at the point the expression is resolved. This resolution
670 -- takes place within the body of the initialization procedure, where
671 -- the discriminant is replaced by its discriminal.
675 then
678 -- Ada 2005 (AI-326): Tagged incomplete types allowed. The wrong usages
679 -- are handled by Analyze_Access_Attribute, Analyze_Assignment,
680 -- Analyze_Object_Renaming, and Freeze_Entity.
686 E_Incomplete_Type
688 then
690 else
695 -------------------------
696 -- Check_Ghost_Context --
697 -------------------------
701 -- Verify that the Ghost policy at the point of declaration of entity Id
702 -- matches the policy at the point of reference. If this is not the case
703 -- emit an error at Err_N.
706 -- Determine whether node Context denotes a Ghost-friendly context where
707 -- a Ghost entity can safely reside.
709 -------------------------
710 -- Is_OK_Ghost_Context --
711 -------------------------
715 -- Determine whether node Decl is a Ghost declaration or appears
716 -- within a Ghost declaration.
718 --------------------------
719 -- Is_Ghost_Declaration --
720 --------------------------
727 begin
728 -- Climb the parent chain looking for an object declaration
733 when N_Abstract_Subprogram_Declaration |
734 N_Exception_Declaration |
735 N_Exception_Renaming_Declaration |
736 N_Full_Type_Declaration |
737 N_Generic_Function_Renaming_Declaration |
738 N_Generic_Package_Declaration |
739 N_Generic_Package_Renaming_Declaration |
740 N_Generic_Procedure_Renaming_Declaration |
741 N_Generic_Subprogram_Declaration |
742 N_Number_Declaration |
743 N_Object_Declaration |
744 N_Object_Renaming_Declaration |
745 N_Package_Declaration |
746 N_Package_Renaming_Declaration |
747 N_Private_Extension_Declaration |
748 N_Private_Type_Declaration |
749 N_Subprogram_Declaration |
750 N_Subprogram_Renaming_Declaration |
751 N_Subtype_Declaration =>
758 -- Special cases
760 -- A reference to a Ghost entity may appear as the default
761 -- expression of a formal parameter of a subprogram body. This
762 -- context must be treated as suitable because the relation
763 -- between the spec and the body has not been established and
764 -- the body is not marked as Ghost yet. The real check was
765 -- performed on the spec.
769 then
772 -- References to Ghost entities may be relocated in internally
773 -- generated bodies.
777 then
780 -- The original context is an expression function that has
781 -- been split into a spec and a body. The context is OK as
782 -- long as the the initial declaration is Ghost.
785 Subp_Decl :=
793 -- Otherwise this is either an internal body or an internal
794 -- completion. Both are OK because the real check was done
795 -- before expansion activities.
800 -- Prevent the search from going too far
812 -- Start of processing for Is_OK_Ghost_Context
814 begin
815 -- The Ghost entity appears within an assertion expression
820 -- The Ghost entity is part of a declaration or its completion
825 -- The Ghost entity is referenced within a Ghost statement
830 else
835 ------------------------
836 -- Check_Ghost_Policy --
837 ------------------------
842 begin
843 -- The Ghost policy in effect a the point of declaration and at the
844 -- point of use must match (SPARK RM 6.9(14)).
862 -- Start of processing for Check_Ghost_Context
864 begin
865 -- Once it has been established that the reference to the Ghost entity
866 -- is within a suitable context, ensure that the policy at the point of
867 -- declaration and at the point of use match.
872 -- Otherwise the Ghost entity appears in a non-Ghost context and affects
873 -- its behavior or value.
875 else
876 Error_Msg_N
878 Ghost_Ref);
882 ------------------------------
883 -- Check_Infinite_Recursion --
884 ------------------------------
891 -- Check whether list of actuals is identical to list of formals of
892 -- called function (which is also the enclosing scope).
894 ------------------------
895 -- Same_Argument_List --
896 ------------------------
903 begin
906 else
915 then
926 -- Start of processing for Check_Infinite_Recursion
928 begin
929 -- Special case, if this is a procedure call and is a call to the
930 -- current procedure with the same argument list, then this is for
931 -- sure an infinite recursion and we insert a call to raise SE.
935 and then Same_Argument_List
936 then
937 declare
939 begin
943 then
955 -- If not that special case, search up tree, quitting if we reach a
956 -- construct (e.g. a conditional) that tells us that this is not a
957 -- case for an infinite recursion warning.
960 loop
963 -- If no parent, then we were not inside a subprogram, this can for
964 -- example happen when processing certain pragmas in a spec. Just
965 -- return False in this case.
971 -- Done if we get to subprogram body, this is definitely an infinite
972 -- recursion case if we did not find anything to stop us.
976 -- If appearing in conditional, result is false
979 N_And_Then,
980 N_Case_Expression,
981 N_Case_Statement,
982 N_If_Expression,
983 N_If_Statement)
984 then
989 then
990 -- If the call is the expression of a return statement and the
991 -- actuals are identical to the formals, it's worth a warning.
992 -- However, we skip this if there is an immediately preceding
993 -- raise statement, since the call is never executed.
995 -- Furthermore, this corresponds to a common idiom:
997 -- function F (L : Thing) return Boolean is
998 -- begin
999 -- raise Program_Error;
1000 -- return F (L);
1001 -- end F;
1003 -- for generating a stub function
1006 and then Same_Argument_List
1007 then
1010 -- OK, return statement is in a statement list, look for raise
1012 declare
1015 begin
1016 -- Skip past N_Freeze_Entity nodes generated by expansion
1021 loop
1025 -- If no raise statement, give warning. We look at the
1026 -- original node, because in the case of "raise ... with
1027 -- ...", the node has been transformed into a call.
1030 and then
1038 else
1050 -------------------------------
1051 -- Check_Initialization_Call --
1052 -------------------------------
1058 -- Check whether the creation of an object of the type will involve
1059 -- use of the secondary stack. If T is a record type, this is true
1060 -- if the expression for some component uses the secondary stack, e.g.
1061 -- through a call to a function that returns an unconstrained value.
1062 -- False if T is controlled, because cleanups occur elsewhere.
1064 -------------
1065 -- Uses_SS --
1066 -------------
1073 begin
1074 -- Normally we want to use the underlying type, but if it's not set
1075 -- then continue with T.
1092 then
1093 -- The expression for a dynamic component may be rewritten
1094 -- as a dereference, so retrieve original node.
1098 -- Return True if the expression is a call to a function
1099 -- (including an attribute function such as Image, or a
1100 -- user-defined operator) with a result that requires a
1101 -- transient scope.
1108 then
1121 else
1126 -- Start of processing for Check_Initialization_Call
1128 begin
1129 -- Establish a transient scope if the type needs it
1136 ---------------------------------------
1137 -- Check_No_Direct_Boolean_Operators --
1138 ---------------------------------------
1141 begin
1144 then
1145 -- Restriction only applies to original source code
1152 -- Do style check (but skip if in instance, error is on template)
1161 ------------------------------
1162 -- Check_Parameterless_Call --
1163 ------------------------------
1169 -- If the prefix is of an access_to_subprogram type, the node must be
1170 -- rewritten as a call. Ditto if the prefix is overloaded and all its
1171 -- interpretations are access to subprograms.
1173 ---------------------------
1174 -- Prefix_Is_Access_Subp --
1175 ---------------------------
1181 begin
1182 -- If the context is an attribute reference that can apply to
1183 -- functions, this is never a parameterless call (RM 4.1.4(6)).
1187 Name_Code_Address,
1188 Name_Access)
1189 then
1194 return
1197 else
1202 then
1213 -- Start of processing for Check_Parameterless_Call
1215 begin
1216 -- Defend against junk stuff if errors already detected
1223 then
1230 -- If the context expects a value, and the name is a procedure, this is
1231 -- most likely a missing 'Access. Don't try to resolve the parameterless
1232 -- call, error will be caught when the outer call is analyzed.
1237 and then
1239 N_Function_Call,
1240 N_Procedure_Call_Statement)
1241 then
1245 -- Rewrite as call if overloadable entity that is (or could be, in the
1246 -- overloaded case) a function call. If we know for sure that the entity
1247 -- is an enumeration literal, we do not rewrite it.
1249 -- If the entity is the name of an operator, it cannot be a call because
1250 -- operators cannot have default parameters. In this case, this must be
1251 -- a string whose contents coincide with an operator name. Set the kind
1252 -- of the node appropriately.
1260 -- Rewrite as call if it is an explicit dereference of an expression of
1261 -- a subprogram access type, and the subprogram type is not that of a
1262 -- procedure or entry.
1264 or else
1267 -- Rewrite as call if it is a selected component which is a function,
1268 -- this is the case of a call to a protected function (which may be
1269 -- overloaded with other protected operations).
1271 or else
1274 or else
1276 E_Procedure)
1279 -- If one of the above three conditions is met, rewrite as call. Apply
1280 -- the rewriting only once.
1282 then
1285 then
1287 -- This may be a prefixed call that was not fully analyzed, e.g.
1288 -- an actual in an instance.
1293 then
1301 -- The node is the name of the parameterless call. Preserve its
1302 -- descendants, which may be complex expressions.
1306 -- If overloaded, overload set belongs to new copy
1310 -- Change node to parameterless function call (note that the
1311 -- Parameter_Associations associations field is left set to Empty,
1312 -- its normal default value since there are no parameters)
1330 --------------------------------
1331 -- Is_Atomic_Ref_With_Address --
1332 --------------------------------
1337 begin
1341 else
1342 declare
1345 begin
1353 -----------------------------
1354 -- Is_Definite_Access_Type --
1355 -----------------------------
1359 begin
1365 ----------------------
1366 -- Is_Predefined_Op --
1367 ----------------------
1370 begin
1371 -- Predefined operators are intrinsic subprograms
1377 -- A call to a back-end builtin is never a predefined operator
1388 -----------------------------
1389 -- Make_Call_Into_Operator --
1390 -----------------------------
1392 procedure Make_Call_Into_Operator
1396 is
1411 -- If the operand is not universal, and the operator is given by an
1412 -- expanded name, verify that the operand has an interpretation with a
1413 -- type defined in the given scope of the operator.
1416 -- Find a type of the given class in package Pack that contains the
1417 -- operator.
1419 ---------------------------
1420 -- Operand_Type_In_Scope --
1421 ---------------------------
1428 begin
1432 else
1446 ---------------
1447 -- Type_In_P --
1448 ---------------
1454 -- Verify that node is not part of the type declaration for the
1455 -- candidate type, which would otherwise be invisible.
1457 -------------
1458 -- In_Decl --
1459 -------------
1465 begin
1474 else
1477 loop
1480 else
1489 -- Start of processing for Type_In_P
1491 begin
1492 -- If the context type is declared in the prefix package, this is the
1493 -- desired base type.
1498 else
1502 and then not In_Decl
1503 then
1514 -- Start of processing for Make_Call_Into_Operator
1516 begin
1519 -- Binary operator
1529 -- Unary operator
1531 else
1537 -- If the operator is denoted by an expanded name, and the prefix is
1538 -- not Standard, but the operator is a predefined one whose scope is
1539 -- Standard, then this is an implicit_operator, inserted as an
1540 -- interpretation by the procedure of the same name. This procedure
1541 -- overestimates the presence of implicit operators, because it does
1542 -- not examine the type of the operands. Verify now that the operand
1543 -- type appears in the given scope. If right operand is universal,
1544 -- check the other operand. In the case of concatenation, either
1545 -- argument can be the component type, so check the type of the result.
1546 -- If both arguments are literals, look for a type of the right kind
1547 -- defined in the given scope. This elaborate nonsense is brought to
1548 -- you courtesy of b33302a. The type itself must be frozen, so we must
1549 -- find the type of the proper class in the given scope.
1551 -- A final wrinkle is the multiplication operator for fixed point types,
1552 -- which is defined in Standard only, and not in the scope of the
1553 -- fixed point type itself.
1558 -- If this is a package renaming, get renamed entity, which will be
1559 -- the scope of the operands if operaton is type-correct.
1565 -- If the entity being called is defined in the given package, it is
1566 -- a renaming of a predefined operator, and known to be legal.
1570 then
1573 -- Visibility does not need to be checked in an instance: if the
1574 -- operator was not visible in the generic it has been diagnosed
1575 -- already, else there is an implicit copy of it in the instance.
1583 then
1588 -- Ada 2005 AI-420: Predefined equality on Universal_Access is
1589 -- available.
1594 then
1597 else
1606 and then Is_Binary
1608 then
1614 -- Verify that the scope contains a type that corresponds to
1615 -- the given literal. Optimize the case where Pack is Standard.
1637 else
1646 else
1655 then
1658 -- If the type is defined elsewhere, and the operator is not
1659 -- defined in the given scope (by a renaming declaration, e.g.)
1660 -- then this is an error as well. If an extension of System is
1661 -- present, and the type may be defined there, Pack must be
1662 -- System itself.
1669 then
1672 else
1678 then
1685 Error_Msg_NE
1690 -- Detect a mismatch between the context type and the result type
1691 -- in the named package, which is otherwise not detected if the
1692 -- operands are universal. Check is only needed if source entity is
1693 -- an operator, not a function that renames an operator.
1700 and then not In_Instance
1701 then
1704 then
1705 -- Already checked above
1709 -- Operator may be defined in an extension of System
1713 then
1716 else
1717 -- Could we use Wrong_Type here??? (this would require setting
1718 -- Etype (N) to the actual type found where Typ was expected).
1729 else
1733 -- If this is a call to a function that renames a predefined equality,
1734 -- the renaming declaration provides a type that must be used to
1735 -- resolve the operands. This must be done now because resolution of
1736 -- the equality node will not resolve any remaining ambiguity, and it
1737 -- assumes that the first operand is not overloaded.
1742 then
1750 -- Do rewrite setting Comes_From_Source on the result if the original
1751 -- call came from source. Although it is not strictly the case that the
1752 -- operator as such comes from the source, logically it corresponds
1753 -- exactly to the function call in the source, so it should be marked
1754 -- this way (e.g. to make sure that validity checks work fine).
1756 declare
1758 begin
1763 -- If this is an arithmetic operator and the result type is private,
1764 -- the operands and the result must be wrapped in conversion to
1765 -- expose the underlying numeric type and expand the proper checks,
1766 -- e.g. on division.
1770 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
1771 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
1780 else
1784 -- If in ASIS_Mode, propagate operand types to original actuals of
1785 -- function call, which would otherwise not be fully resolved. If
1786 -- the call has already been constant-folded, nothing to do. We
1787 -- relocate the operand nodes rather than copy them, to preserve
1788 -- original_node pointers, given that the operands themselves may
1789 -- have been rewritten. If the call was itself a rewriting of an
1790 -- operator node, nothing to do.
1792 if ASIS_Mode
1795 then
1801 else
1810 -------------------
1811 -- Operator_Kind --
1812 -------------------
1814 function Operator_Kind
1817 is
1820 begin
1821 -- Use CASE statement or array???
1858 else
1862 -- Unary operators
1864 else
1873 else
1881 ----------------------------
1882 -- Preanalyze_And_Resolve --
1883 ----------------------------
1888 begin
1892 -- Normally, we suppress all checks for this preanalysis. There is no
1893 -- point in processing them now, since they will be applied properly
1894 -- and in the proper location when the default expressions reanalyzed
1895 -- and reexpanded later on. We will also have more information at that
1896 -- point for possible suppression of individual checks.
1898 -- However, in SPARK mode, most expansion is suppressed, and this
1899 -- later reanalysis and reexpansion may not occur. SPARK mode does
1900 -- require the setting of checking flags for proof purposes, so we
1901 -- do the SPARK preanalysis without suppressing checks.
1903 -- This special handling for SPARK mode is required for example in the
1904 -- case of Ada 2012 constructs such as quantified expressions, which are
1905 -- expanded in two separate steps.
1909 else
1913 Expander_Mode_Restore;
1917 -- Version without context type
1922 begin
1929 Expander_Mode_Restore;
1933 ----------------------------------
1934 -- Replace_Actual_Discriminants --
1935 ----------------------------------
1942 -- Comment needed???
1944 -------------------
1945 -- Process_Discr --
1946 -------------------
1951 begin
1957 then
1973 -- Start of processing for Replace_Actual_Discriminants
1975 begin
1989 else
1994 -------------
1995 -- Resolve --
1996 -------------
2012 -- Determine whether a node comes from a predefined library unit or
2013 -- Standard.
2016 -- Try and fix up a literal so that it matches its expected type. New
2017 -- literals are manufactured if necessary to avoid cascaded errors.
2020 -- Additional diagnostics when an ambiguous call has an ambiguous
2021 -- argument (typically a controlling actual).
2024 -- Called when attempt at resolving current expression fails
2026 ------------------------------------
2027 -- Comes_From_Predefined_Lib_Unit --
2028 -------------------------------------
2031 begin
2032 return
2034 or else Is_Predefined_File_Name
2038 --------------------
2039 -- Patch_Up_Value --
2040 --------------------
2043 begin
2060 then
2065 Char_Literal_Value =>
2081 -------------------------------
2082 -- Report_Ambiguous_Argument --
2083 -------------------------------
2090 begin
2094 then
2097 -- Could use comments on what is going on here???
2105 else
2114 -----------------------
2115 -- Resolution_Failed --
2116 -----------------------
2119 begin
2125 -- The caller will return without calling the expander, so we need
2126 -- to set the analyzed flag. Note that it is fine to set Analyzed
2127 -- to True even if we are in the middle of a shallow analysis,
2128 -- (see the spec of sem for more details) since this is an error
2129 -- situation anyway, and there is no point in repeating the
2130 -- analysis later (indeed it won't work to repeat it later, since
2131 -- we haven't got a clear resolution of which entity is being
2132 -- referenced.)
2138 -- Start of processing for Resolve
2140 begin
2145 -- Access attribute on remote subprogram cannot be used for a non-remote
2146 -- access-to-subprogram type.
2150 Name_Unrestricted_Access,
2151 Name_Unchecked_Access)
2157 then
2158 Error_Msg_N
2164 -- If the context is a Remote_Access_To_Subprogram, access attributes
2165 -- must be resolved with the corresponding fat pointer. There is no need
2166 -- to check for the attribute name since the return type of an
2167 -- attribute is never a remote type.
2172 then
2173 declare
2181 begin
2182 -- Check that Typ is a remote access-to-subprogram type
2186 -- Prefix (N) must statically denote a remote subprogram
2187 -- declared in a package specification.
2191 Attr = Attribute_Unrestricted_Access
2192 then
2207 or else
2209 then
2211 Error_Msg_N
2213 N);
2216 -- If we are generating code in distributed mode, perform
2217 -- semantic checks against corresponding remote entities.
2219 if Expander_Active
2221 then
2222 Check_Subtype_Conformant
2224 Old_Id => Designated_Type
2250 then
2255 -- Return if already analyzed
2262 -- Any case of Any_Type as the Etype value means that we had a
2263 -- previous error.
2272 -- The resolution of an Expression_With_Actions is determined by
2273 -- its Expression.
2281 -- If not overloaded, then we know the type, and all that needs doing
2282 -- is to check that this type is compatible with the context.
2288 -- In the overloaded case, we must select the interpretation that
2289 -- is compatible with the context (i.e. the type passed to Resolve)
2291 else
2292 -- Loop through possible interpretations
2302 -- We are only interested in interpretations that are compatible
2303 -- with the expected type, any other interpretations are ignored.
2308 Write_Eol;
2311 else
2312 -- Skip the current interpretation if it is disabled by an
2313 -- abstract operator. This action is performed only when the
2314 -- type against which we are resolving is the same as the
2315 -- type of the interpretation.
2322 then
2330 -- First matching interpretation
2338 -- Matching interpretation that is not the first, maybe an
2339 -- error, but there are some cases where preference rules are
2340 -- used to choose between the two possibilities. These and
2341 -- some more obscure cases are handled in Disambiguate.
2343 else
2344 -- If the current statement is part of a predefined library
2345 -- unit, then all interpretations which come from user level
2346 -- packages should not be considered. Check previous and
2347 -- current one.
2355 -- Previous interpretation must be discarded
2365 -- Otherwise apply further disambiguation steps
2370 -- Disambiguation has succeeded. Skip the remaining
2371 -- interpretations.
2381 else
2382 -- Before we issue an ambiguity complaint, check for
2383 -- the case of a subprogram call where at least one
2384 -- of the arguments is Any_Type, and if so, suppress
2385 -- the message, since it is a cascaded error.
2388 declare
2392 begin
2404 Write_Eol;
2417 then
2422 then
2426 -- Not that special case, so issue message using the
2427 -- flag Ambiguous to control printing of the header
2428 -- message only at the start of an ambiguous set.
2433 then
2434 Error_Msg_N
2437 else
2438 Error_Msg_NE -- CODEFIX
2446 Error_Msg_N
2448 else
2449 Error_Msg_N -- CODEFIX
2455 then
2456 Report_Ambiguous_Argument;
2462 -- By default, the error message refers to the candidate
2463 -- interpretation. But if it is a predefined operator, it
2464 -- is implicitly declared at the declaration of the type
2465 -- of the operand. Recover the sloc of that declaration
2466 -- for the error message.
2472 Standard_Standard
2473 then
2478 then
2486 Standard_Standard
2487 then
2492 then
2496 -- If this is an indirect call, use the subprogram_type
2497 -- in the message, to have a meaningful location. Also
2498 -- indicate if this is an inherited operation, created
2499 -- by a type declaration.
2504 then
2506 Error_Msg_Sloc :=
2508 else
2515 then
2516 -- Special-case the message for universal_fixed
2517 -- operators, which are not declared with the type
2518 -- of the operand, but appear forever in Standard.
2522 then
2523 Error_Msg_N
2526 else
2527 Error_Msg_N
2531 elsif
2533 then
2534 Error_Msg_N
2536 else
2537 Error_Msg_N -- CODEFIX
2544 -- We have a matching interpretation, Expr_Type is the type
2545 -- from this interpretation, and Seen is the entity.
2547 -- For an operator, just set the entity name. The type will be
2548 -- set by the specific operator resolution routine.
2563 -- AI05-0139-2: Expression is overloaded because type has
2564 -- implicit dereference. If type matches context, no implicit
2565 -- dereference is involved.
2576 then
2577 -- If the node is a general indexing, the dereference is
2578 -- is inserted when resolving the rewritten form, else
2579 -- insert it now.
2583 then
2587 -- For an explicit dereference, attribute reference, range,
2588 -- short-circuit form (which is not an operator node), or call
2589 -- with a name that is an explicit dereference, there is
2590 -- nothing to be done at this point.
2593 N_Attribute_Reference,
2594 N_And_Then,
2595 N_Indexed_Component,
2596 N_Or_Else,
2597 N_Range,
2598 N_Selected_Component,
2599 N_Slice)
2601 then
2604 -- For procedure or function calls, set the type of the name,
2605 -- and also the entity pointer for the prefix.
2609 then
2616 then
2621 -- For all other cases, just set the type of the Name
2623 else
2631 -- Move to next interpretation
2639 -- At this stage Found indicates whether or not an acceptable
2640 -- interpretation exists. If not, then we have an error, except that if
2641 -- the context is Any_Type as a result of some other error, then we
2642 -- suppress the error report.
2647 -- If type we are looking for is Void, then this is the procedure
2648 -- call case, and the error is simply that what we gave is not a
2649 -- procedure name (we think of procedure calls as expressions with
2650 -- types internally, but the user doesn't think of them this way).
2654 -- Special case message if function used as a procedure
2659 then
2660 Error_Msg_NE
2664 -- Otherwise give general message (not clear what cases this
2665 -- covers, but no harm in providing for them).
2667 else
2673 -- Otherwise we do have a subexpression with the wrong type
2675 -- Check for the case of an allocator which uses an access type
2676 -- instead of the designated type. This is a common error and we
2677 -- specialize the message, posting an error on the operand of the
2678 -- allocator, complaining that we expected the designated type of
2679 -- the allocator.
2685 then
2689 -- Check for view mismatch on Null in instances, for which the
2690 -- view-swapping mechanism has no identifier.
2696 then
2701 -- Check for an aggregate. Sometimes we can get bogus aggregates
2702 -- from misuse of parentheses, and we are about to complain about
2703 -- the aggregate without even looking inside it.
2705 -- Instead, if we have an aggregate of type Any_Composite, then
2706 -- analyze and resolve the component fields, and then only issue
2707 -- another message if we get no errors doing this (otherwise
2708 -- assume that the errors in the aggregate caused the problem).
2712 then
2713 -- Disable expansion in any case. If there is a type mismatch
2714 -- it may be fatal to try to expand the aggregate. The flag
2715 -- would otherwise be set to false when the error is posted.
2719 declare
2721 -- Check one aggregate, and set Found to True if we have a
2722 -- definite error in any of its elements
2725 -- Check one element of aggregate and set Found to True if
2726 -- we definitely have an error in the element.
2728 ----------------
2729 -- Check_Aggr --
2730 ----------------
2735 begin
2748 -- If this is a default-initialized component, then
2749 -- there is nothing to check. The box will be
2750 -- replaced by the appropriate call during late
2751 -- expansion.
2762 ----------------
2763 -- Check_Elmt --
2764 ----------------
2767 begin
2768 -- If we have a nested aggregate, go inside it (to
2769 -- attempt a naked analyze-resolve of the aggregate can
2770 -- cause undesirable cascaded errors). Do not resolve
2771 -- expression if it needs a type from context, as for
2772 -- integer * fixed expression.
2777 else
2782 then
2792 begin
2797 -- Looks like we have a type error, but check for special case
2798 -- of Address wanted, integer found, with the configuration pragma
2799 -- Allow_Integer_Address active. If we have this case, introduce
2800 -- an unchecked conversion to allow the integer expression to be
2801 -- treated as an Address. The reverse case of integer wanted,
2802 -- Address found, is treated in an analogous manner.
2810 -- That special Allow_Integer_Address check did not appply, so we
2811 -- have a real type error. If an error message was issued already,
2812 -- Found got reset to True, so if it's still False, issue standard
2813 -- Wrong_Type message.
2817 declare
2820 begin
2826 -- Protected operation: retrieve operation name
2830 else
2835 Error_Msg_NE
2841 declare
2845 begin
2852 Error_Msg_NE
2858 else
2862 else
2868 Resolution_Failed;
2871 -- Test if we have more than one interpretation for the context
2874 Resolution_Failed;
2877 -- Only one intepretation
2879 else
2880 -- In Ada 2005, if we have something like "X : T := 2 + 2;", where
2881 -- the "+" on T is abstract, and the operands are of universal type,
2882 -- the above code will have (incorrectly) resolved the "+" to the
2883 -- universal one in Standard. Therefore check for this case and give
2884 -- an error. We can't do this earlier, because it would cause legal
2885 -- cases to get errors (when some other type has an abstract "+").
2891 then
2896 then
2897 Error_Msg_NE
2906 -- Here we have an acceptable interpretation for the context
2908 -- Propagate type information and normalize tree for various
2909 -- predefined operations. If the context only imposes a class of
2910 -- types, rather than a specific type, propagate the actual type
2911 -- downward.
2917 Typ = Any_Discrete
2918 then
2921 -- Any_Fixed is legal in a real context only if a specific fixed-
2922 -- point type is imposed. If Norman Cohen can be confused by this,
2923 -- it deserves a separate message.
2927 then
2934 -- A user-defined operator is transformed into a function call at
2935 -- this point, so that further processing knows that operators are
2936 -- really operators (i.e. are predefined operators). User-defined
2937 -- operators that are intrinsic are just renamings of the predefined
2938 -- ones, and need not be turned into calls either, but if they rename
2939 -- a different operator, we must transform the node accordingly.
2940 -- Instantiations of Unchecked_Conversion are intrinsic but are
2941 -- treated as functions, even if given an operator designator.
2946 then
2952 and then
2954 N_Subprogram_Renaming_Declaration
2955 then
2958 -- If the node is rewritten, it will be fully resolved in
2959 -- Rewrite_Renamed_Operator.
2969 when N_Aggregate => Resolve_Aggregate (N, Ctx_Type);
2971 when N_Allocator => Resolve_Allocator (N, Ctx_Type);
2973 when N_Short_Circuit
2974 => Resolve_Short_Circuit (N, Ctx_Type);
2976 when N_Attribute_Reference
2977 => Resolve_Attribute (N, Ctx_Type);
2979 when N_Case_Expression
2980 => Resolve_Case_Expression (N, Ctx_Type);
2982 when N_Character_Literal
2983 => Resolve_Character_Literal (N, Ctx_Type);
2985 when N_Expanded_Name
2986 => Resolve_Entity_Name (N, Ctx_Type);
2988 when N_Explicit_Dereference
2989 => Resolve_Explicit_Dereference (N, Ctx_Type);
2991 when N_Expression_With_Actions
2992 => Resolve_Expression_With_Actions (N, Ctx_Type);
2994 when N_Extension_Aggregate
2995 => Resolve_Extension_Aggregate (N, Ctx_Type);
2997 when N_Function_Call
2998 => Resolve_Call (N, Ctx_Type);
3000 when N_Identifier
3001 => Resolve_Entity_Name (N, Ctx_Type);
3003 when N_If_Expression
3004 => Resolve_If_Expression (N, Ctx_Type);
3006 when N_Indexed_Component
3007 => Resolve_Indexed_Component (N, Ctx_Type);
3009 when N_Integer_Literal
3010 => Resolve_Integer_Literal (N, Ctx_Type);
3012 when N_Membership_Test
3013 => Resolve_Membership_Op (N, Ctx_Type);
3015 when N_Null => Resolve_Null (N, Ctx_Type);
3017 when N_Op_And | N_Op_Or | N_Op_Xor
3018 => Resolve_Logical_Op (N, Ctx_Type);
3020 when N_Op_Eq | N_Op_Ne
3021 => Resolve_Equality_Op (N, Ctx_Type);
3023 when N_Op_Lt | N_Op_Le | N_Op_Gt | N_Op_Ge
3024 => Resolve_Comparison_Op (N, Ctx_Type);
3026 when N_Op_Not => Resolve_Op_Not (N, Ctx_Type);
3028 when N_Op_Add | N_Op_Subtract | N_Op_Multiply |
3029 N_Op_Divide | N_Op_Mod | N_Op_Rem
3031 => Resolve_Arithmetic_Op (N, Ctx_Type);
3033 when N_Op_Concat => Resolve_Op_Concat (N, Ctx_Type);
3035 when N_Op_Expon => Resolve_Op_Expon (N, Ctx_Type);
3037 when N_Op_Plus | N_Op_Minus | N_Op_Abs
3038 => Resolve_Unary_Op (N, Ctx_Type);
3040 when N_Op_Shift => Resolve_Shift (N, Ctx_Type);
3042 when N_Procedure_Call_Statement
3043 => Resolve_Call (N, Ctx_Type);
3045 when N_Operator_Symbol
3046 => Resolve_Operator_Symbol (N, Ctx_Type);
3048 when N_Qualified_Expression
3049 => Resolve_Qualified_Expression (N, Ctx_Type);
3051 -- Why is the following null, needs a comment ???
3053 when N_Quantified_Expression
3054 => null;
3056 when N_Raise_Expression
3057 => Resolve_Raise_Expression (N, Ctx_Type);
3059 when N_Raise_xxx_Error
3060 => Set_Etype (N, Ctx_Type);
3062 when N_Range => Resolve_Range (N, Ctx_Type);
3064 when N_Real_Literal
3065 => Resolve_Real_Literal (N, Ctx_Type);
3067 when N_Reference => Resolve_Reference (N, Ctx_Type);
3069 when N_Selected_Component
3070 => Resolve_Selected_Component (N, Ctx_Type);
3072 when N_Slice => Resolve_Slice (N, Ctx_Type);
3074 when N_String_Literal
3075 => Resolve_String_Literal (N, Ctx_Type);
3077 when N_Type_Conversion
3078 => Resolve_Type_Conversion (N, Ctx_Type);
3080 when N_Unchecked_Expression =>
3081 Resolve_Unchecked_Expression (N, Ctx_Type);
3083 when N_Unchecked_Type_Conversion =>
3084 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
3085 end case;
3087 -- Ada 2012 (AI05-0149): Apply an (implicit) conversion to an
3088 -- expression of an anonymous access type that occurs in the context
3089 -- of a named general access type, except when the expression is that
3090 -- of a membership test. This ensures proper legality checking in
3091 -- terms of allowed conversions (expressions that would be illegal to
3092 -- convert implicitly are allowed in membership tests).
3094 if Ada_Version >= Ada_2012
3095 and then Ekind (Ctx_Type) = E_General_Access_Type
3096 and then Ekind (Etype (N)) = E_Anonymous_Access_Type
3097 and then Nkind (Parent (N)) not in N_Membership_Test
3098 then
3099 Rewrite (N, Convert_To (Ctx_Type, Relocate_Node (N)));
3100 Analyze_And_Resolve (N, Ctx_Type);
3101 end if;
3103 -- If the subexpression was replaced by a non-subexpression, then
3104 -- all we do is to expand it. The only legitimate case we know of
3105 -- is converting procedure call statement to entry call statements,
3106 -- but there may be others, so we are making this test general.
3108 if Nkind (N) not in N_Subexpr then
3109 Debug_A_Exit ("resolving ", N, " (done)");
3110 Expand (N);
3111 return;
3112 end if;
3114 -- The expression is definitely NOT overloaded at this point, so
3115 -- we reset the Is_Overloaded flag to avoid any confusion when
3116 -- reanalyzing the node.
3118 Set_Is_Overloaded (N, False);
3120 -- Freeze expression type, entity if it is a name, and designated
3121 -- type if it is an allocator (RM 13.14(10,11,13)).
3123 -- Now that the resolution of the type of the node is complete, and
3124 -- we did not detect an error, we can expand this node. We skip the
3125 -- expand call if we are in a default expression, see section
3126 -- "Handling of Default Expressions" in Sem spec.
3128 Debug_A_Exit ("resolving ", N, " (done)");
3130 -- We unconditionally freeze the expression, even if we are in
3131 -- default expression mode (the Freeze_Expression routine tests this
3132 -- flag and only freezes static types if it is set).
3134 -- Ada 2012 (AI05-177): The declaration of an expression function
3135 -- does not cause freezing, but we never reach here in that case.
3136 -- Here we are resolving the corresponding expanded body, so we do
3137 -- need to perform normal freezing.
3139 Freeze_Expression (N);
3141 -- Now we can do the expansion
3143 Expand (N);
3144 end if;
3145 end Resolve;
3147 -------------
3148 -- Resolve --
3149 -------------
3151 -- Version with check(s) suppressed
3153 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
3154 begin
3155 if Suppress = All_Checks then
3156 declare
3157 Sva : constant Suppress_Array := Scope_Suppress.Suppress;
3158 begin
3159 Scope_Suppress.Suppress := (others => True);
3160 Resolve (N, Typ);
3161 Scope_Suppress.Suppress := Sva;
3162 end;
3164 else
3165 declare
3166 Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
3167 begin
3168 Scope_Suppress.Suppress (Suppress) := True;
3169 Resolve (N, Typ);
3170 Scope_Suppress.Suppress (Suppress) := Svg;
3171 end;
3172 end if;
3173 end Resolve;
3175 -------------
3176 -- Resolve --
3177 -------------
3179 -- Version with implicit type
3181 procedure Resolve (N : Node_Id) is
3182 begin
3183 Resolve (N, Etype (N));
3184 end Resolve;
3186 ---------------------
3187 -- Resolve_Actuals --
3188 ---------------------
3190 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
3191 Loc : constant Source_Ptr := Sloc (N);
3192 A : Node_Id;
3193 A_Id : Entity_Id;
3194 A_Typ : Entity_Id;
3195 F : Entity_Id;
3196 F_Typ : Entity_Id;
3197 Prev : Node_Id := Empty;
3198 Orig_A : Node_Id;
3200 procedure Check_Aliased_Parameter;
3201 -- Check rules on aliased parameters and related accessibility rules
3202 -- in (RM 3.10.2 (10.2-10.4)).
3204 procedure Check_Argument_Order;
3205 -- Performs a check for the case where the actuals are all simple
3206 -- identifiers that correspond to the formal names, but in the wrong
3207 -- order, which is considered suspicious and cause for a warning.
3209 procedure Check_Prefixed_Call;
3210 -- If the original node is an overloaded call in prefix notation,
3212 -- Try_Object_Operation has already verified that there is a valid
3213 -- interpretation, but the form of the actual can only be determined
3214 -- once the primitive operation is identified.
3217 -- If the actual is missing in a call, insert in the actuals list
3218 -- an instance of the default expression. The insertion is always
3219 -- a named association.
3221 procedure Property_Error
3225 -- Emit an error concerning variable Var with entity Var_Id that has
3226 -- enabled property Prop_Nam when it acts as an actual parameter in a
3227 -- call and the corresponding formal parameter is of mode IN.
3230 -- Check whether T1 and T2, or their full views, are derived from a
3231 -- common type. Used to enforce the restrictions on array conversions
3232 -- of AI95-00246.
3235 -- Predicate to determine whether an actual that is a concatenation
3236 -- will be evaluated statically and does not need a transient scope.
3237 -- This must be determined before the actual is resolved and expanded
3238 -- because if needed the transient scope must be introduced earlier.
3240 ------------------------------
3241 -- Check_Aliased_Parameter --
3242 ------------------------------
3247 begin
3255 else
3262 -- In a generic body assume the worst for generic formals:
3263 -- they can have a constrained partial view (AI05-041).
3269 then
3272 else
3277 else
3289 then
3297 then
3298 Error_Msg_N
3304 --------------------------
3305 -- Check_Argument_Order --
3306 --------------------------
3309 begin
3310 -- Nothing to do if no parameters, or original node is neither a
3311 -- function call nor a procedure call statement (happens in the
3312 -- operator-transformed-to-function call case), or the call does
3313 -- not come from source, or this warning is off.
3315 if not Warn_On_Parameter_Order
3319 then
3323 declare
3326 begin
3327 -- Nothing to do if only one parameter
3333 -- Here if at least two arguments
3335 declare
3341 -- Set True if an out of order case is found
3343 begin
3344 -- Collect identifier names of actuals, fail if any actual is
3345 -- not a simple identifier, and record max length of name.
3351 else
3357 -- If we got this far, all actuals are identifiers and the list
3358 -- of their names is stored in the Actuals array.
3363 -- If we ran out of formals, that's odd, probably an error
3364 -- which will be detected elsewhere, but abandon the search.
3370 -- If name matches and is in order OK
3375 else
3376 -- If no match, see if it is elsewhere in list and if so
3377 -- flag potential wrong order if type is compatible.
3381 and then
3383 then
3389 -- No match
3397 -- If Formals left over, also probably an error, skip warning
3403 -- Here we give the warning if something was out of order
3406 Error_Msg_N
3413 -------------------------
3414 -- Check_Prefixed_Call --
3415 -------------------------
3424 begin
3425 -- Check whether the call is a prefixed call, with or without
3426 -- additional actuals.
3429 or else
3435 then
3438 then
3439 -- Introduce dereference on object in prefix
3441 New_A :=
3449 then
3450 -- Introduce an implicit 'Access in prefix
3453 Error_Msg_NE
3469 --------------------
3470 -- Insert_Default --
3471 --------------------
3477 begin
3478 -- Missing argument in call, nothing to insert
3483 else
3484 -- Note that we do a full New_Copy_Tree, so that any associated
3485 -- Itypes are properly copied. This may not be needed any more,
3486 -- but it does no harm as a safety measure. Defaults of a generic
3487 -- formal may be out of bounds of the corresponding actual (see
3488 -- cc1311b) and an additional check may be required.
3490 Actval :=
3491 New_Copy_Tree
3498 then
3504 then
3507 then
3508 -- If default is a real literal, do not introduce a
3509 -- conversion whose effect may depend on the run-time
3510 -- size of universal real.
3514 else
3525 -- Resolve aggregates with their base type, to avoid scope
3526 -- anomalies: the subtype was first built in the subprogram
3527 -- declaration, and the current call may be nested.
3531 else
3535 else
3538 -- See note above concerning aggregates
3542 then
3545 -- Resolve entities with their own type, which may differ from
3546 -- the type of a reference in a generic context (the view
3547 -- swapping mechanism did not anticipate the re-analysis of
3548 -- default values in calls).
3553 else
3558 -- If default is a tag indeterminate function call, propagate tag
3559 -- to obtain proper dispatching.
3563 then
3569 -- If the default expression raises constraint error, then just
3570 -- silently replace it with an N_Raise_Constraint_Error node, since
3571 -- we already gave the warning on the subprogram spec. If node is
3572 -- already a Raise_Constraint_Error leave as is, to prevent loops in
3573 -- the warnings removal machinery.
3577 then
3585 Assoc :=
3590 -- Case of insertion is first named actual
3594 then
3601 else
3605 else
3609 -- Case of insertion is not first named actual
3611 else
3612 Set_Next_Named_Actual
3624 --------------------
3625 -- Property_Error --
3626 --------------------
3628 procedure Property_Error
3632 is
3633 begin
3635 Error_Msg_NE
3641 -------------------
3642 -- Same_Ancestor --
3643 -------------------
3649 begin
3652 then
3658 then
3665 --------------------------
3666 -- Static_Concatenation --
3667 --------------------------
3670 begin
3677 -- Concatenation is static when both operands are static and
3678 -- the concatenation operator is a predefined one.
3681 and then
3683 and then
3688 declare
3690 begin
3693 and then
3697 else
3703 -- Start of processing for Resolve_Actuals
3705 begin
3706 Check_Argument_Order;
3710 Check_Prefixed_Call;
3719 -- If we have an error in any actual or formal, indicated by a type
3720 -- of Any_Type, then abandon resolution attempt, and set result type
3721 -- to Any_Type. Skip this if the actual is a Raise_Expression, whose
3722 -- type is imposed from context.
3726 then
3733 -- Case where actual is present
3735 -- If the actual is an entity, generate a reference to it now. We
3736 -- do this before the actual is resolved, because a formal of some
3737 -- protected subprogram, or a task discriminant, will be rewritten
3738 -- during expansion, and the source entity reference may be lost.
3743 then
3749 then
3756 -- RM 6.4.1(12): For an out parameter that is passed by
3757 -- copy, the formal parameter object is created, and:
3759 -- * For an access type, the formal parameter is initialized
3760 -- from the value of the actual, without checking that the
3761 -- value satisfies any constraint, any predicate, or any
3762 -- exclusion of the null value.
3764 -- * For a scalar type that has the Default_Value aspect
3765 -- specified, the formal parameter is initialized from the
3766 -- value of the actual, without checking that the value
3767 -- satisfies any constraint or any predicate.
3768 -- I do not understand why this case is included??? this is
3769 -- not a case where an OUT parameter is treated as IN OUT.
3771 -- * For a composite type with discriminants or that has
3772 -- implicit initial values for any subcomponents, the
3773 -- behavior is as for an in out parameter passed by copy.
3775 -- Hence for these cases we generate the read reference now
3776 -- (the write reference will be generated later by
3777 -- Note_Possible_Modification).
3780 and then
3782 or else
3784 and then
3786 or else
3789 or else Is_Partially_Initialized_Type
3791 then
3801 then
3802 -- If style checking mode on, check match of formal name
3810 -- If the formal is Out or In_Out, do not resolve and expand the
3811 -- conversion, because it is subsequently expanded into explicit
3812 -- temporaries and assignments. However, the object of the
3813 -- conversion can be resolved. An exception is the case of tagged
3814 -- type conversion with a class-wide actual. In that case we want
3815 -- the tag check to occur and no temporary will be needed (no
3816 -- representation change can occur) and the parameter is passed by
3817 -- reference, so we go ahead and resolve the type conversion.
3818 -- Another exception is the case of reference to component or
3819 -- subcomponent of a bit-packed array, in which case we want to
3820 -- defer expansion to the point the in and out assignments are
3821 -- performed.
3826 then
3829 then
3830 -- In a view conversion, the conversion must be legal in
3831 -- both directions, and thus both component types must be
3832 -- aliased, or neither (4.6 (8)).
3834 -- The extra rule in 4.6 (24.9.2) seems unduly restrictive:
3835 -- the privacy requirement should not apply to generic
3836 -- types, and should be checked in an instance. ARG query
3837 -- is in order ???
3841 then
3842 Error_Msg_N
3846 -- Comment here??? what set of cases???
3848 elsif
3850 then
3851 -- Check view conv between unrelated by ref array types
3855 then
3856 Error_Msg_N
3860 -- In Ada 2005 mode, check view conversion component
3861 -- type cannot be private, tagged, or volatile. Note
3862 -- that we only apply this to source conversions. The
3863 -- generated code can contain conversions which are
3864 -- not subject to this test, and we cannot extract the
3865 -- component type in such cases since it is not present.
3869 then
3870 declare
3872 Component_Type
3874 begin
3879 then
3880 Error_Msg_N
3891 -- Resolve expression if conversion is all OK
3896 then
3900 -- If the actual is a function call that returns a limited
3901 -- unconstrained object that needs finalization, create a
3902 -- transient scope for it, so that it can receive the proper
3903 -- finalization list.
3908 and then Expander_Active
3910 then
3914 -- A small optimization: if one of the actuals is a concatenation
3915 -- create a block around a procedure call to recover stack space.
3916 -- This alleviates stack usage when several procedure calls in
3917 -- the same statement list use concatenation. We do not perform
3918 -- this wrapping for code statements, where the argument is a
3919 -- static string, and we want to preserve warnings involving
3920 -- sequences of such statements.
3924 and then Expander_Active
3925 and then
3929 then
3933 else
3937 and then
3940 then
3941 Error_Msg_N
3954 -- (Ada 2005: AI-251): If the actual is an allocator whose
3955 -- directly designated type is a class-wide interface, we build
3956 -- an anonymous access type to use it as the type of the
3957 -- allocator. Later, when the subprogram call is expanded, if
3958 -- the interface has a secondary dispatch table the expander
3959 -- will add a type conversion to force the correct displacement
3960 -- of the pointer.
3963 declare
3969 begin
3972 then
3975 Set_Directly_Designated_Type
3980 -- Ada 2005, AI-162:If the actual is an allocator, the
3981 -- innermost enclosing statement is the master of the
3982 -- created object. This needs to be done with expansion
3983 -- enabled only, otherwise the transient scope will not
3984 -- be removed in the expansion of the wrapped construct.
3987 and then Expander_Active
3988 then
3998 -- (Ada 2005): The call may be to a primitive operation of a
3999 -- tagged synchronized type, declared outside of the type. In
4000 -- this case the controlling actual must be converted to its
4001 -- corresponding record type, which is the formal type. The
4002 -- actual may be a subtype, either because of a constraint or
4003 -- because it is a generic actual, so use base type to locate
4004 -- concurrent type.
4011 then
4012 -- If the actual is overloaded, look for an interpretation
4013 -- that has a synchronized type.
4018 else
4019 declare
4023 begin
4028 then
4038 declare
4041 begin
4044 else
4048 -- Tagged synchronized type (case 1): the actual is a
4049 -- concurrent type.
4053 then
4055 Unchecked_Convert_To
4059 -- Tagged synchronized type (case 2): the formal is a
4060 -- concurrent type.
4063 and then Present
4068 then
4071 -- Common case
4073 else
4078 -- Not a synchronized operation
4080 else
4088 -- An actual cannot be an untagged formal incomplete type
4093 then
4094 Error_Msg_N
4100 N_Procedure_Call_Statement)
4101 then
4102 -- In formal mode, check that actual parameters matching
4103 -- formals of tagged types are objects (or ancestor type
4104 -- conversions of objects), not general expressions.
4111 declare
4116 begin
4118 Check_SPARK_05_Restriction
4121 -- In formal mode, the only view conversions are those
4122 -- involving ancestor conversion of an extended type.
4124 elsif not
4130 then
4131 if Ekind_In
4133 then
4134 Check_SPARK_05_Restriction
4137 else
4138 Check_SPARK_05_Restriction
4142 else
4147 else
4151 -- In formal mode, the only view conversions are those
4152 -- involving ancestor conversion of an extended type.
4156 then
4157 Check_SPARK_05_Restriction
4163 -- has warnings suppressed, then we reset Never_Set_In_Source for
4164 -- the calling entity. The reason for this is to catch cases like
4165 -- GNAT.Spitbol.Patterns.Vstring_Var where the called subprogram
4166 -- uses trickery to modify an IN parameter.
4173 then
4177 -- Perform error checks for IN and IN OUT parameters
4181 -- Check unset reference. For scalar parameters, it is clearly
4182 -- wrong to pass an uninitialized value as either an IN or
4183 -- IN-OUT parameter. For composites, it is also clearly an
4184 -- error to pass a completely uninitialized value as an IN
4185 -- parameter, but the case of IN OUT is trickier. We prefer
4186 -- not to give a warning here. For example, suppose there is
4187 -- a routine that sets some component of a record to False.
4188 -- It is perfectly reasonable to make this IN-OUT and allow
4189 -- either initialized or uninitialized records to be passed
4190 -- in this case.
4192 -- For partially initialized composite values, we also avoid
4193 -- warnings, since it is quite likely that we are passing a
4194 -- partially initialized value and only the initialized fields
4195 -- will in fact be read in the subprogram.
4200 then
4204 -- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
4205 -- actual to a nested call, since this is case of reading an
4206 -- out parameter, which is not allowed.
4211 then
4216 -- Case of OUT or IN OUT parameter
4220 -- For an Out parameter, check for useless assignment. Note
4221 -- that we can't set Last_Assignment this early, because we may
4222 -- kill current values in Resolve_Call, and that call would
4223 -- clobber the Last_Assignment field.
4225 -- Note: call Warn_On_Useless_Assignment before doing the check
4226 -- below for Is_OK_Variable_For_Out_Formal so that the setting
4227 -- of Referenced_As_LHS/Referenced_As_Out_Formal properly
4228 -- reflects the last assignment, not this one.
4235 then
4240 -- Validate the form of the actual. Note that the call to
4241 -- Is_OK_Variable_For_Out_Formal generates the required
4242 -- reference in this case.
4244 -- A call to an initialization procedure for an aggregate
4245 -- component may initialize a nested component of a constant
4246 -- designated object. In this context the object is variable.
4250 then
4254 and then
4257 then
4258 Error_Msg_N
4264 -- What's the following about???
4268 else
4269 Kill_All_Checks;
4278 -- Apply appropriate constraint/predicate checks for IN [OUT] case
4282 -- Apply predicate tests except in certain special cases. Note
4283 -- that it might be more consistent to apply these only when
4284 -- expansion is active (in Exp_Ch6.Expand_Actuals), as we do
4285 -- for the outbound predicate tests ???
4291 -- Apply required constraint checks
4293 -- Gigi looks at the check flag and uses the appropriate types.
4294 -- For now since one flag is used there is an optimization
4295 -- which might not be done in the IN OUT case since Gigi does
4296 -- not do any analysis. More thought required about this ???
4298 -- In fact is this comment obsolete??? doesn't the expander now
4299 -- generate all these tests anyway???
4312 then
4315 -- For view conversions of a discriminated object, apply
4316 -- check to object itself, the conversion alreay has the
4317 -- proper type.
4321 then
4328 then
4334 then
4337 else
4341 -- Ada 2005 (AI-231): Note that the controlling parameter case
4342 -- already existed in Ada 95, which is partially checked
4343 -- elsewhere (see Checks), and we don't want the warning
4344 -- message to differ.
4349 then
4351 Apply_Compile_Time_Constraint_Error
4357 Apply_Compile_Time_Constraint_Error
4366 -- Checks for OUT parameters and IN OUT parameters
4370 -- If there is a type conversion, to make sure the return value
4371 -- meets the constraints of the variable before the conversion.
4375 Apply_Scalar_Range_Check
4377 else
4378 Apply_Range_Check
4382 -- If no conversion apply scalar range checks and length checks
4383 -- base on the subtype of the actual (NOT that of the formal).
4385 else
4390 then
4392 else
4397 -- Note: we do not apply the predicate checks for the case of
4398 -- OUT and IN OUT parameters. They are instead applied in the
4399 -- Expand_Actuals routine in Exp_Ch6.
4402 -- An actual associated with an access parameter is implicitly
4403 -- converted to the anonymous access type of the formal and must
4404 -- satisfy the legality checks for access conversions.
4408 Error_Msg_N
4412 -- If the actual is an access selected component of a variable,
4413 -- the call may modify its designated object. It is reasonable
4414 -- to treat this as a potential modification of the enclosing
4415 -- record, to prevent spurious warnings that it should be
4416 -- declared as a constant, because intuitively programmers
4417 -- regard the designated subcomponent as part of the record.
4422 then
4427 -- Check bad case of atomic/volatile argument (RM C.6(12))
4431 then
4434 then
4435 Error_Msg_NE
4441 then
4442 Error_Msg_NE
4448 -- Check that subprograms don't have improper controlling
4449 -- arguments (RM 3.9.2 (9)).
4451 -- A primitive operation may have an access parameter of an
4452 -- incomplete tagged type, but a dispatching call is illegal
4453 -- if the type is still incomplete.
4459 declare
4461 begin
4465 then
4466 Error_Msg_NE
4480 then
4485 Error_Msg_NE
4489 -- Apply the checks described in 3.10.2(27): if the context is a
4490 -- specific access-to-object, the actual cannot be class-wide.
4491 -- Use base type to exclude access_to_subprogram cases.
4498 and then
4503 -- Disable these checks for call to imported C++ subprograms
4505 and then not
4509 then
4510 Error_Msg_N
4515 Error_Msg_NE
4520 Check_Aliased_Parameter;
4524 -- If it is a named association, treat the selector_name as a
4525 -- proper identifier, and mark the corresponding entity.
4529 -- Ignore reference in SPARK mode, as it refers to an entity not
4530 -- in scope at the point of reference, so the reference should
4531 -- be ignored for computing effects of subprograms.
4533 and then not GNATprove_Mode
4534 then
4547 -- The following checks are only relevant when SPARK_Mode is on as
4548 -- they are not standard Ada legality rule. Internally generated
4549 -- temporaries are ignored.
4554 then
4555 -- An effectively volatile object may act as an actual
4556 -- parameter when the corresponding formal is of a non-scalar
4557 -- volatile type.
4561 then
4564 -- An effectively volatile object may act as an actual
4565 -- parameter in a call to an instance of Unchecked_Conversion.
4570 else
4571 Error_Msg_N
4576 -- Detect an external variable with an enabled property that
4577 -- does not match the mode of the corresponding formal in a
4578 -- procedure call. Functions are not considered because they
4579 -- cannot have effectively volatile formal parameters in the
4580 -- first place.
4586 then
4600 then
4602 Error_Msg_NE
4606 Error_Msg_N
4612 -- A formal parameter of a specific tagged type whose related
4613 -- subprogram is subject to pragma Extensions_Visible with value
4614 -- "False" cannot act as an actual in a subprogram with value
4615 -- "True" (SPARK RM 6.1.7(3)).
4619 Extensions_Visible_True
4620 then
4621 Error_Msg_N
4624 Error_Msg_NE
4628 -- The actual parameter of a Ghost subprogram whose formal is of
4629 -- mode IN OUT or OUT must be a Ghost variable (SPARK RM 6.9(13)).
4636 then
4637 Error_Msg_NE
4643 else
4650 -- Case where actual is not present
4652 else
4653 Insert_Default;
4660 -----------------------
4661 -- Resolve_Allocator --
4662 -----------------------
4674 procedure Check_Allocator_Discrim_Accessibility
4677 -- Check that accessibility level associated with an access discriminant
4678 -- initialized in an allocator by the expression Disc_Exp is not deeper
4679 -- than the level of the allocator type Alloc_Typ. An error message is
4680 -- issued if this condition is violated. Specialized checks are done for
4681 -- the cases of a constraint expression which is an access attribute or
4682 -- an access discriminant.
4685 -- If the allocator is an actual in a call, it is allowed to be class-
4686 -- wide when the context is not because it is a controlling actual.
4688 -------------------------------------------
4689 -- Check_Allocator_Discrim_Accessibility --
4690 -------------------------------------------
4692 procedure Check_Allocator_Discrim_Accessibility
4695 is
4696 begin
4699 then
4700 Error_Msg_N
4703 -- When the expression is an Access attribute the level of the prefix
4704 -- object must not be deeper than that of the allocator's type.
4708 Attribute_Access
4711 then
4712 Error_Msg_N
4714 Disc_Exp);
4716 -- When the expression is an access discriminant the check is against
4717 -- the level of the prefix object.
4723 then
4724 Error_Msg_N
4726 Disc_Exp);
4728 -- All other cases are legal
4730 else
4735 ----------------------------
4736 -- In_Dispatching_Context --
4737 ----------------------------
4742 begin
4748 -- Start of processing for Resolve_Allocator
4750 begin
4751 -- Replace general access with specific type
4761 -- For qualified expression, resolve the expression using the given
4762 -- subtype (nothing to do for type mark, subtype indication)
4767 and then not In_Dispatching_Context
4768 then
4769 Error_Msg_N
4777 -- A qualified expression requires an exact match of the type.
4778 -- Class-wide matching is not allowed.
4783 then
4787 -- Calls to build-in-place functions are not currently supported in
4788 -- allocators for access types associated with a simple storage pool.
4789 -- Supporting such allocators may require passing additional implicit
4790 -- parameters to build-in-place functions (or a significant revision
4791 -- of the current b-i-p implementation to unify the handling for
4792 -- multiple kinds of storage pools). ???
4796 then
4797 declare
4800 begin
4802 and then
4803 Present (Get_Rep_Pragma
4805 then
4806 Error_Msg_N
4813 -- A special accessibility check is needed for allocators that
4814 -- constrain access discriminants. The level of the type of the
4815 -- expression used to constrain an access discriminant cannot be
4816 -- deeper than the type of the allocator (in contrast to access
4817 -- parameters, where the level of the actual can be arbitrary).
4819 -- We can't use Valid_Conversion to perform this check because in
4820 -- general the type of the allocator is unrelated to the type of
4821 -- the access discriminant.
4825 then
4832 then
4835 -- Get the first component expression of the aggregate
4845 else
4849 else
4868 else
4873 else
4882 -- For a subtype mark or subtype indication, freeze the subtype
4884 else
4888 Error_Msg_N
4892 -- A special accessibility check is needed for allocators that
4893 -- constrain access discriminants. The level of the type of the
4894 -- expression used to constrain an access discriminant cannot be
4895 -- deeper than the type of the allocator (in contrast to access
4896 -- parameters, where the level of the actual can be arbitrary).
4897 -- We can't use Valid_Conversion to perform this check because
4898 -- in general the type of the allocator is unrelated to the type
4899 -- of the access discriminant.
4904 then
4914 else
4928 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
4929 -- check that the level of the type of the created object is not deeper
4930 -- than the level of the allocator's access type, since extensions can
4931 -- now occur at deeper levels than their ancestor types. This is a
4932 -- static accessibility level check; a run-time check is also needed in
4933 -- the case of an initialized allocator with a class-wide argument (see
4934 -- Expand_Allocator_Expression).
4938 then
4939 declare
4942 begin
4947 else
4953 then
4956 Error_Msg_N
4965 -- Do not apply Ada 2005 accessibility checks on a class-wide
4966 -- allocator if the type given in the allocator is a formal
4967 -- type. A run-time check will be performed in the instance.
4977 -- Check for allocation from an empty storage pool
4982 -- If the context is an unchecked conversion, as may happen within an
4983 -- inlined subprogram, the allocator is being resolved with its own
4984 -- anonymous type. In that case, if the target type has a specific
4985 -- storage pool, it must be inherited explicitly by the allocator type.
4989 then
4990 Set_Associated_Storage_Pool
4998 -- Check that an allocator with task parts isn't for a nested access
4999 -- type when restriction No_Task_Hierarchy applies.
5003 then
5007 -- An illegal allocator may be rewritten as a raise Program_Error
5008 -- statement.
5012 -- An anonymous access discriminant is the definition of a
5013 -- coextension.
5017 N_Discriminant_Specification
5018 then
5019 declare
5023 begin
5026 -- Ada 2012 AI05-0052: If the designated type of the allocator
5027 -- is limited, then the allocator shall not be used to define
5028 -- the value of an access discriminant unless the discriminated
5029 -- type is immutably limited.
5034 then
5035 Error_Msg_N
5041 -- Avoid marking an allocator as a dynamic coextension if it is
5042 -- within a static construct.
5048 -- Cleanup for potential static coextensions
5050 else
5056 -- Report a simple error: if the designated object is a local task,
5057 -- its body has not been seen yet, and its activation will fail an
5058 -- elaboration check.
5065 then
5071 -- Ada 2012 (AI05-0111-3): Detect an attempt to allocate a task or a
5072 -- type with a task component on a subpool. This action must raise
5073 -- Program_Error at runtime.
5079 then
5091 ---------------------------
5092 -- Resolve_Arithmetic_Op --
5093 ---------------------------
5095 -- Used for resolving all arithmetic operators except exponentiation
5106 -- We do the resolution using the base type, because intermediate values
5107 -- in expressions always are of the base type, not a subtype of it.
5110 -- Returns True if N is in a context that expects "any real type"
5113 -- Return True iff given type is Integer or universal real/integer
5116 -- Choose type of integer literal in fixed-point operation to conform
5117 -- to available fixed-point type. T is the type of the other operand,
5118 -- which is needed to determine the expected type of N.
5121 -- Set operand type to T if universal
5123 -------------------------------
5124 -- Expected_Type_Is_Any_Real --
5125 -------------------------------
5128 begin
5129 -- N is the expression after "delta" in a fixed_point_definition;
5130 -- see RM-3.5.9(6):
5133 N_Decimal_Fixed_Point_Definition,
5135 -- N is one of the bounds in a real_range_specification;
5136 -- see RM-3.5.7(5):
5138 N_Real_Range_Specification,
5140 -- N is the expression of a delta_constraint;
5141 -- see RM-J.3(3):
5143 N_Delta_Constraint);
5146 -----------------------------
5147 -- Is_Integer_Or_Universal --
5148 -----------------------------
5155 begin
5161 else
5167 then
5178 ----------------------------
5179 -- Set_Mixed_Mode_Operand --
5180 ----------------------------
5186 begin
5189 -- A universal integer literal is resolved as standard integer
5190 -- except in the case of a fixed-point result, where we leave it
5191 -- as universal (to be handled by Exp_Fixd later on)
5195 else
5203 then
5204 -- A universal real can appear in a fixed-type context. We resolve
5205 -- the literal with that context, even though this might raise an
5206 -- exception prematurely (the other operand may be zero).
5213 then
5214 -- Integer arg in mixed-mode operation. Resolve with universal
5215 -- type, in case preference rule must be applied.
5221 then
5222 -- Not a mixed-mode operation, resolve with context
5228 -- N may itself be a mixed-mode operation, so use context type
5235 then
5236 -- Must be (fixed * fixed) operation, operand must have one
5237 -- compatible interpretation.
5244 then
5245 -- C * F(X) in a fixed context, where C is a real literal or a
5246 -- fixed-point expression. F must have either a fixed type
5247 -- interpretation or an integer interpretation, but not both.
5254 else
5261 else
5269 -- Reanalyze the literal with the fixed type of the context. If
5270 -- context is Universal_Fixed, we are within a conversion, leave
5271 -- the literal as a universal real because there is no usable
5272 -- fixed type, and the target of the conversion plays no role in
5273 -- the resolution.
5275 declare
5279 begin
5282 else
5288 then
5290 else
5298 else
5303 ----------------------
5304 -- Set_Operand_Type --
5305 ----------------------
5308 begin
5311 then
5316 -- Start of processing for Resolve_Arithmetic_Op
5318 begin
5323 then
5327 -- Special-case for mixed-mode universal expressions or fixed point type
5328 -- operation: each argument is resolved separately. The same treatment
5329 -- is required if one of the operands of a fixed point operation is
5330 -- universal real, since in this case we don't do a conversion to a
5331 -- specific fixed-point type (instead the expander handles the case).
5333 -- Set the type of the node to its universal interpretation because
5334 -- legality checks on an exponentiation operand need the context.
5339 then
5350 or else
5353 then
5358 -- If context is a fixed type and one operand is integer, the other
5359 -- is resolved with the type of the context.
5364 then
5371 then
5375 else
5380 -- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
5381 -- multiplying operators from being used when the expected type is
5382 -- also universal_fixed. Note that B_Typ will be Universal_Fixed in
5383 -- some cases where the expected type is actually Any_Real;
5384 -- Expected_Type_Is_Any_Real takes care of that case.
5388 then
5392 N_Unchecked_Type_Conversion)
5393 then
5400 else
5403 and then not
5405 N_Unchecked_Type_Conversion)
5406 then
5407 Error_Msg_N
5412 -- The expected type is "any real type" in contexts like
5414 -- type T is delta <universal_fixed-expression> ...
5416 -- in which case we need to set the type to Universal_Real
5417 -- so that static expression evaluation will work properly.
5421 else
5431 then
5436 -- If no previous errors, this is only possible if one operand is
5437 -- overloaded and the context is universal. Resolve as such.
5442 else
5444 and then
5446 then
5450 -- If the context is Universal_Fixed and the operands are also
5451 -- universal fixed, this is an error, unless there is only one
5452 -- applicable fixed_point type (usually Duration).
5460 else
5465 else
5470 -- If one of the arguments was resolved to a non-universal type.
5471 -- label the result of the operation itself with the same type.
5472 -- Do the same for the universal argument, if any.
5484 -- In SPARK, a multiplication or division with operands of fixed point
5485 -- types must be qualified or explicitly converted to identify the
5486 -- result type.
5491 and then
5493 then
5494 Check_SPARK_05_Restriction
5498 -- Set overflow and division checking bit
5505 -- Give warning if explicit division by zero
5509 then
5515 or else
5518 then
5519 -- Specialize the warning message according to the operation.
5520 -- The following warnings are for the case
5525 -- For division, we have two cases, for float division
5526 -- of an unconstrained float type, on a machine where
5527 -- Machine_Overflows is false, we don't get an exception
5528 -- at run-time, but rather an infinity or Nan. The Nan
5529 -- case is pretty obscure, so just warn about infinities.
5533 and then not Machine_Overflows_On_Target
5534 then
5535 Error_Msg_N
5539 -- For all other cases, we get a Constraint_Error
5541 else
5542 Apply_Compile_Time_Constraint_Error
5548 Apply_Compile_Time_Constraint_Error
5553 Apply_Compile_Time_Constraint_Error
5557 -- Division by zero can only happen with division, rem,
5558 -- and mod operations.
5564 -- Otherwise just set the flag to check at run time
5566 else
5571 -- If Restriction No_Implicit_Conditionals is active, then it is
5572 -- violated if either operand can be negative for mod, or for rem
5573 -- if both operands can be negative.
5577 then
5578 declare
5585 -- Set if corresponding operand might be negative
5587 begin
5588 Determine_Range
5592 Determine_Range
5596 -- Check if we will be generating conditionals. There are two
5597 -- cases where that can happen, first for REM, the only case
5598 -- is largest negative integer mod -1, where the division can
5599 -- overflow, but we still have to give the right result. The
5600 -- front end generates a test for this annoying case. Here we
5601 -- just test if both operands can be negative (that's what the
5602 -- expander does, so we match its logic here).
5604 -- The second case is mod where either operand can be negative.
5605 -- In this case, the back end has to generate additional tests.
5608 or else
5610 then
5622 ------------------
5623 -- Resolve_Call --
5624 ------------------
5627 function Same_Or_Aliased_Subprograms
5630 -- Returns True if the subprogram entity S is the same as E or else
5631 -- S is an alias of E.
5633 ---------------------------------
5634 -- Same_Or_Aliased_Subprograms --
5635 ---------------------------------
5637 function Same_Or_Aliased_Subprograms
5640 is
5642 begin
5646 -- Local variables
5660 -- Start of processing for Resolve_Call
5662 begin
5663 -- The context imposes a unique interpretation with type Typ on a
5664 -- procedure or function call. Find the entity of the subprogram that
5665 -- yields the expected type, and propagate the corresponding formal
5666 -- constraints on the actuals. The caller has established that an
5667 -- interpretation exists, and emitted an error if not unique.
5669 -- First deal with the case of a call to an access-to-subprogram,
5670 -- dereference made explicit in Analyze_Call.
5676 else
5677 -- Find the interpretation whose type (a subprogram type) has a
5678 -- return type that is compatible with the context. Analysis of
5679 -- the node has established that one exists.
5698 -- If the prefix is not an entity, then resolve it
5704 -- For an indirect call, we always invalidate checks, since we do not
5705 -- know whether the subprogram is local or global. Yes we could do
5706 -- better here, e.g. by knowing that there are no local subprograms,
5707 -- but it does not seem worth the effort. Similarly, we kill all
5708 -- knowledge of current constant values.
5710 Kill_Current_Values;
5712 -- If this is a procedure call which is really an entry call, do
5713 -- the conversion of the procedure call to an entry call. Protected
5714 -- operations use the same circuitry because the name in the call
5715 -- can be an arbitrary expression with special resolution rules.
5720 then
5724 -- Kill checks and constant values, as above for indirect case
5725 -- Who knows what happens when another task is activated?
5727 Kill_Current_Values;
5730 -- Normal subprogram call with name established in Resolve
5736 -- Otherwise we must have the case of an overloaded call
5738 else
5741 -- Initialize Nam to prevent warning (we know it will be assigned
5742 -- in the loop below, but the compiler does not know that).
5762 then
5763 -- The prefix is a parameterless function call that returns an access
5764 -- to subprogram. If parameters are present in the current call, add
5765 -- add an explicit dereference. We use the base type here because
5766 -- within an instance these may be subtypes.
5768 -- The dereference is added either in Analyze_Call or here. Should
5769 -- be consolidated ???
5778 -- Check that a call to Current_Task does not occur in an entry body
5781 declare
5784 begin
5786 loop
5789 -- Exclude calls that occur within the default of a formal
5790 -- parameter of the entry, since those are evaluated outside
5791 -- of the body.
5798 then
5801 Error_Msg_NE
5815 -- Check that a procedure call does not occur in the context of the
5816 -- entry call statement of a conditional or timed entry call. Note that
5817 -- the case of a call to a subprogram renaming of an entry will also be
5818 -- rejected. The test for N not being an N_Entry_Call_Statement is
5819 -- defensive, covering the possibility that the processing of entry
5820 -- calls might reach this point due to later modifications of the code
5821 -- above.
5826 then
5830 -- Ada 2005 (AI-345): If a procedure_call_statement is used
5831 -- for a procedure_or_entry_call, the procedure_name or
5832 -- procedure_prefix of the procedure_call_statement shall denote
5833 -- an entry renamed by a procedure, or (a view of) a primitive
5834 -- subprogram of a limited interface whose first parameter is
5835 -- a controlling parameter.
5840 then
5841 Error_Msg_N
5846 -- If the SPARK_05 restriction is active, we are not allowed
5847 -- to have a call to a subprogram before we see its completion.
5852 -- Don't flag strange internal calls
5857 -- Only flag calls in extended main source
5862 -- Exclude enumeration literals from this processing
5865 then
5866 Check_SPARK_05_Restriction
5870 -- Check that this is not a call to a protected procedure or entry from
5871 -- within a protected function.
5875 -- Freeze the subprogram name if not in a spec-expression. Note that
5876 -- we freeze procedure calls as well as function calls. Procedure calls
5877 -- are not frozen according to the rules (RM 13.14(14)) because it is
5878 -- impossible to have a procedure call to a non-frozen procedure in
5879 -- pure Ada, but in the code that we generate in the expander, this
5880 -- rule needs extending because we can generate procedure calls that
5881 -- need freezing.
5883 -- In Ada 2012, expression functions may be called within pre/post
5884 -- conditions of subsequent functions or expression functions. Such
5885 -- calls do not freeze when they appear within generated bodies,
5886 -- (including the body of another expression function) which would
5887 -- place the freeze node in the wrong scope. An expression function
5888 -- is frozen in the usual fashion, by the appearance of a real body,
5889 -- or at the end of a declarative part.
5893 and then
5896 then
5900 -- For a predefined operator, the type of the result is the type imposed
5901 -- by context, except for a predefined operation on universal fixed.
5902 -- Otherwise The type of the call is the type returned by the subprogram
5903 -- being called.
5910 -- If the subprogram returns an array type, and the context requires the
5911 -- component type of that array type, the node is really an indexing of
5912 -- the parameterless call. Resolve as such. A pathological case occurs
5913 -- when the type of the component is an access to the array type. In
5914 -- this case the call is truly ambiguous.
5917 and then
5920 or else
5923 and then
5925 then
5926 declare
5931 begin
5934 then
5935 Error_Msg_N
5937 else
5940 -- The called entity may be an explicit dereference, in which
5941 -- case there is no entity to set.
5949 or else
5951 and then
5953 then
5956 -- Indexed call to a parameterless function
5958 Index_Node :=
5960 Prefix =>
5963 else
5964 -- An Ada 2005 prefixed call to a primitive operation
5965 -- whose first parameter is the prefix. This prefix was
5966 -- prepended to the parameter list, which is actually a
5967 -- list of indexes. Remove the prefix in order to build
5968 -- the proper indexed component.
5970 Index_Node :=
5972 Prefix =>
5975 Parameter_Associations =>
5976 New_List
5981 -- Preserve the parenthesis count of the node
5985 -- Since we are correcting a node classification error made
5986 -- by the parser, we call Replace rather than Rewrite.
6000 else
6004 -- In the case where the call is to an overloaded subprogram, Analyze
6005 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
6006 -- such a case Normalize_Actuals needs to be called once more to order
6007 -- the actuals correctly. Otherwise the call will have the ordering
6008 -- given by the last overloaded subprogram whether this is the correct
6009 -- one being called or not.
6016 -- In any case, call is fully resolved now. Reset Overload flag, to
6017 -- prevent subsequent overload resolution if node is analyzed again
6022 -- A Ghost entity must appear in a specific context
6028 -- If we are calling the current subprogram from immediately within its
6029 -- body, then that is the case where we can sometimes detect cases of
6030 -- infinite recursion statically. Do not try this in case restriction
6031 -- No_Recursion is in effect anyway, and do it only for source calls.
6036 -- Check violation of SPARK_05 restriction which does not permit
6037 -- a subprogram body to contain a call to the subprogram directly.
6041 then
6042 Check_SPARK_05_Restriction
6046 -- Issue warning for possible infinite recursion in the absence
6047 -- of the No_Recursion restriction.
6052 then
6053 -- Here we detected and flagged an infinite recursion, so we do
6054 -- not need to test the case below for further warnings. Also we
6055 -- are all done if we now have a raise SE node.
6061 -- If call is to immediately containing subprogram, then check for
6062 -- the case of a possible run-time detectable infinite recursion.
6064 else
6068 -- Although in general case, recursion is not statically
6069 -- checkable, the case of calling an immediately containing
6070 -- subprogram is easy to catch.
6074 -- If the recursive call is to a parameterless subprogram,
6075 -- then even if we can't statically detect infinite
6076 -- recursion, this is pretty suspicious, and we output a
6077 -- warning. Furthermore, we will try later to detect some
6078 -- cases here at run time by expanding checking code (see
6079 -- Detect_Infinite_Recursion in package Exp_Ch6).
6081 -- If the recursive call is within a handler, do not emit a
6082 -- warning, because this is a common idiom: loop until input
6083 -- is correct, catch illegal input in handler and restart.
6089 then
6090 -- For the case of a procedure call. We give the message
6091 -- only if the call is the first statement in a sequence
6092 -- of statements, or if all previous statements are
6093 -- simple assignments. This is simply a heuristic to
6094 -- decrease false positives, without losing too many good
6095 -- warnings. The idea is that these previous statements
6096 -- may affect global variables the procedure depends on.
6097 -- We also exclude raise statements, that may arise from
6098 -- constraint checks and are probably unrelated to the
6099 -- intended control flow.
6103 then
6104 declare
6106 begin
6110 N_Raise_Constraint_Error)
6111 then
6120 -- Do not give warning if we are in a conditional context
6122 declare
6124 begin
6130 then
6135 -- Here warning is to be issued
6151 -- Check obsolescent reference to Ada.Characters.Handling subprogram
6155 -- If subprogram name is a predefined operator, it was given in
6156 -- functional notation. Replace call node with operator node, so
6157 -- that actuals can be resolved appropriately.
6165 then
6171 -- Create a transient scope if the resulting type requires it
6173 -- There are several notable exceptions:
6175 -- a) In init procs, the transient scope overhead is not needed, and is
6176 -- even incorrect when the call is a nested initialization call for a
6177 -- component whose expansion may generate adjust calls. However, if the
6178 -- call is some other procedure call within an initialization procedure
6179 -- (for example a call to Create_Task in the init_proc of the task
6180 -- run-time record) a transient scope must be created around this call.
6182 -- b) Enumeration literal pseudo-calls need no transient scope
6184 -- c) Intrinsic subprograms (Unchecked_Conversion and source info
6185 -- functions) do not use the secondary stack even though the return
6186 -- type may be unconstrained.
6188 -- d) Calls to a build-in-place function, since such functions may
6189 -- allocate their result directly in a target object, and cases where
6190 -- the result does get allocated in the secondary stack are checked for
6191 -- within the specialized Exp_Ch6 procedures for expanding those
6192 -- build-in-place calls.
6194 -- e) If the subprogram is marked Inline_Always, then even if it returns
6195 -- an unconstrained type the call does not require use of the secondary
6196 -- stack. However, inlining will only take place if the body to inline
6197 -- is already present. It may not be available if e.g. the subprogram is
6198 -- declared in a child instance.
6200 -- If this is an initialization call for a type whose construction
6201 -- uses the secondary stack, and it is not a nested call to initialize
6202 -- a component, we do need to create a transient scope for it. We
6203 -- check for this by traversing the type in Check_Initialization_Call.
6209 then
6215 then
6218 elsif Expander_Active
6221 and then
6223 or else
6225 then
6228 -- If the call appears within the bounds of a loop, it will
6229 -- be rewritten and reanalyzed, nothing left to do here.
6236 and then not Within_Init_Proc
6237 then
6241 -- A protected function cannot be called within the definition of the
6242 -- enclosing protected type, unless it is part of a pre/postcondition
6243 -- on another protected operation.
6248 and then not In_Spec_Expression
6249 then
6250 Error_Msg_NE
6254 -- Propagate interpretation to actuals, and add default expressions
6255 -- where needed.
6260 -- Overloaded literals are rewritten as function calls, for purpose of
6261 -- resolution. After resolution, we can replace the call with the
6262 -- literal itself.
6268 -- Avoid validation, since it is a static function call
6274 -- If the subprogram is not global, then kill all saved values and
6275 -- checks. This is a bit conservative, since in many cases we could do
6276 -- better, but it is not worth the effort. Similarly, we kill constant
6277 -- values. However we do not need to do this for internal entities
6278 -- (unless they are inherited user-defined subprograms), since they
6279 -- are not in the business of molesting local values.
6281 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
6282 -- kill all checks and values for calls to global subprograms. This
6283 -- takes care of the case where an access to a local subprogram is
6284 -- taken, and could be passed directly or indirectly and then called
6285 -- from almost any context.
6287 -- Note: we do not do this step till after resolving the actuals. That
6288 -- way we still take advantage of the current value information while
6289 -- scanning the actuals.
6291 -- We suppress killing values if we are processing the nodes associated
6292 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
6293 -- type kills all the values as part of analyzing the code that
6294 -- initializes the dispatch tables.
6298 or else Suppress_Value_Tracking_On_Call
6303 then
6304 Kill_Current_Values;
6307 -- If we are warning about unread OUT parameters, this is the place to
6308 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
6309 -- after the above call to Kill_Current_Values (since that call clears
6310 -- the Last_Assignment field of all local variables).
6315 then
6316 declare
6320 begin
6330 then
6340 -- If the subprogram is a primitive operation, check whether or not
6341 -- it is a correct dispatching call.
6345 then
6350 and then not In_Instance
6351 then
6355 -- If this is a dispatching call, generate the appropriate reference,
6356 -- for better source navigation in GPS.
6360 then
6363 -- Normal case, not a dispatching call: generate a call reference
6365 else
6373 -- Check for violation of restriction No_Specific_Termination_Handlers
6374 -- and warn on a potentially blocking call to Abort_Task.
6378 or else
6380 then
6387 -- A call to Ada.Real_Time.Timing_Events.Set_Handler to set a relative
6388 -- timing event violates restriction No_Relative_Delay (AI-0211). We
6389 -- need to check the second argument to determine whether it is an
6390 -- absolute or relative timing event.
6395 then
6399 -- Issue an error for a call to an eliminated subprogram. This routine
6400 -- will not perform the check if the call appears within a default
6401 -- expression.
6405 -- In formal mode, the primitive operations of a tagged type or type
6406 -- extension do not include functions that return the tagged type.
6412 then
6416 -- Implement rule in 12.5.1 (23.3/2): In an instance, if the actual is
6417 -- class-wide and the call dispatches on result in a context that does
6418 -- not provide a tag, the call raises Program_Error.
6421 and then In_Instance
6426 then
6427 -- Verify that none of the formals are controlling
6429 declare
6433 begin
6455 -- Check for calling a function with OUT or IN OUT parameter when the
6456 -- calling context (us right now) is not Ada 2012, so does not allow
6457 -- OUT or IN OUT parameters in function calls.
6462 then
6467 -- Check the dimensions of the actuals in the call. For function calls,
6468 -- propagate the dimensions from the returned type to N.
6472 -- All done, evaluate call and deal with elaboration issues
6477 -- In GNATprove mode, expansion is disabled, but we want to inline some
6478 -- subprograms to facilitate formal verification. Indirect calls through
6479 -- a subprogram type or within a generic cannot be inlined. Inlining is
6480 -- performed only for calls subject to SPARK_Mode on.
6482 if GNATprove_Mode
6485 and then not Inside_A_Generic
6486 then
6493 -- Nothing to do if the subprogram is not eligible for inlining in
6494 -- GNATprove mode.
6498 then
6501 -- Calls cannot be inlined inside assertions, as GNATprove treats
6502 -- assertions as logic expressions.
6509 -- Calls cannot be inlined inside default expressions
6516 -- Inlining should not be performed during pre-analysis
6520 -- With the one-pass inlining technique, a call cannot be
6521 -- inlined if the corresponding body has not been seen yet.
6524 Error_Msg_NE
6529 -- Nothing to do if there is no body to inline, indicating that
6530 -- the subprogram is not suitable for inlining in GNATprove
6531 -- mode.
6536 -- Calls cannot be inlined inside potentially unevaluated
6537 -- expressions, as this would create complex actions inside
6538 -- expressions, that are not handled by GNATprove.
6542 Error_Msg_N
6546 -- Otherwise, inline the call
6548 else
6558 -----------------------------
6559 -- Resolve_Case_Expression --
6560 -----------------------------
6565 begin
6576 -------------------------------
6577 -- Resolve_Character_Literal --
6578 -------------------------------
6584 begin
6585 -- Verify that the character does belong to the type of the context
6590 -- Wide_Wide_Character literals must always be defined, since the set
6591 -- of wide wide character literals is complete, i.e. if a character
6592 -- literal is accepted by the parser, then it is OK for wide wide
6593 -- character (out of range character literals are rejected).
6598 -- Always accept character literal for type Any_Character, which
6599 -- occurs in error situations and in comparisons of literals, both
6600 -- of which should accept all literals.
6605 -- For Standard.Character or a type derived from it, check that the
6606 -- literal is in range.
6613 -- For Standard.Wide_Character or a type derived from it, check that the
6614 -- literal is in range.
6621 -- For Standard.Wide_Wide_Character or a type derived from it, we
6622 -- know the literal is in range, since the parser checked.
6627 -- If the entity is already set, this has already been resolved in a
6628 -- generic context, or comes from expansion. Nothing else to do.
6633 -- Otherwise we have a user defined character type, and we can use the
6634 -- standard visibility mechanisms to locate the referenced entity.
6636 else
6649 -- If we fall through, then the literal does not match any of the
6650 -- entries of the enumeration type. This isn't just a constraint error
6651 -- situation, it is an illegality (see RM 4.2).
6653 Error_Msg_NE
6657 ---------------------------
6658 -- Resolve_Comparison_Op --
6659 ---------------------------
6661 -- Context requires a boolean type, and plays no role in resolution.
6662 -- Processing identical to that for equality operators. The result type is
6663 -- the base type, which matters when pathological subtypes of booleans with
6664 -- limited ranges are used.
6671 begin
6672 -- If this is an intrinsic operation which is not predefined, use the
6673 -- types of its declared arguments to resolve the possibly overloaded
6674 -- operands. Otherwise the operands are unambiguous and specify the
6675 -- expected type.
6680 else
6691 -- Skip remaining processing if already set to Any_Type
6697 -- Deal with other error cases
6701 T = Any_Character
6702 then
6705 else
6713 -- Resolve the operands if types OK
6722 -- In SPARK, ordering operators <, <=, >, >= are not defined for Boolean
6723 -- types or array types except String.
6726 Check_SPARK_05_Restriction
6731 then
6732 Check_SPARK_05_Restriction
6736 -- Check comparison on unordered enumeration
6740 Error_Msg_NE
6745 -- Evaluate the relation (note we do this after the above check since
6746 -- this Eval call may change N to True/False.
6752 -----------------------------------------
6753 -- Resolve_Discrete_Subtype_Indication --
6754 -----------------------------------------
6756 procedure Resolve_Discrete_Subtype_Indication
6759 is
6763 begin
6771 else
6781 Error_Msg_NE
6784 -- Rewrite the constraint as a range of Typ
6785 -- to allow compilation to proceed further.
6797 else
6801 -- Additionally, we must check that the bounds are compatible
6802 -- with the given subtype, which might be different from the
6803 -- type of the context.
6807 -- ??? If the above check statically detects a Constraint_Error
6808 -- it replaces the offending bound(s) of the range R with a
6809 -- Constraint_Error node. When the itype which uses these bounds
6810 -- is frozen the resulting call to Duplicate_Subexpr generates
6811 -- a new temporary for the bounds.
6813 -- Unfortunately there are other itypes that are also made depend
6814 -- on these bounds, so when Duplicate_Subexpr is called they get
6815 -- a forward reference to the newly created temporaries and Gigi
6816 -- aborts on such forward references. This is probably sign of a
6817 -- more fundamental problem somewhere else in either the order of
6818 -- itype freezing or the way certain itypes are constructed.
6820 -- To get around this problem we call Remove_Side_Effects right
6821 -- away if either bounds of R are a Constraint_Error.
6823 declare
6827 begin
6843 -------------------------
6844 -- Resolve_Entity_Name --
6845 -------------------------
6847 -- Used to resolve identifiers and expanded names
6851 -- Denote whether an arbitrary node Nod appears in a check node
6853 function Is_OK_Volatile_Context
6856 -- Determine whether node Context denotes a "non-interfering context"
6857 -- (as defined in SPARK RM 7.1.3(13)) where volatile reference Obj_Ref
6858 -- can safely reside.
6860 ----------------------
6861 -- Appears_In_Check --
6862 ----------------------
6867 begin
6868 -- Climb the parent chain looking for a check node
6875 -- Prevent the search from going too far
6887 ----------------------------
6888 -- Is_OK_Volatile_Context --
6889 ----------------------------
6891 function Is_OK_Volatile_Context
6894 is
6895 begin
6896 -- The volatile object appears on either side of an assignment
6901 -- The volatile object is part of the initialization expression of
6902 -- another object. Ensure that the climb of the parent chain came
6903 -- from the expression side and not from the name side.
6908 then
6911 -- The volatile object appears as an actual parameter in a call to an
6912 -- instance of Unchecked_Conversion whose result is renamed.
6917 then
6920 -- The volatile object appears as the prefix of a name occurring
6921 -- in a non-interfering context.
6924 N_Indexed_Component,
6925 N_Selected_Component,
6926 N_Slice)
6928 and then Is_OK_Volatile_Context
6931 then
6934 -- The volatile object appears as the expression of a type conversion
6935 -- occurring in a non-interfering context.
6938 N_Unchecked_Type_Conversion)
6940 and then Is_OK_Volatile_Context
6943 then
6946 -- Allow references to volatile objects in various checks. This is
6947 -- not a direct SPARK 2014 requirement.
6952 else
6957 -- Local variables
6962 -- Start of processing for Resolve_Entity_Name
6964 begin
6965 -- If garbage from errors, set to Any_Type and return
6972 -- Replace named numbers by corresponding literals. Note that this is
6973 -- the one case where Resolve_Entity_Name must reset the Etype, since
6974 -- it is currently marked as universal.
6984 -- For enumeration literals, we need to make sure that a proper style
6985 -- check is done, since such literals are overloaded, and thus we did
6986 -- not do a style check during the first phase of analysis.
6992 -- Case of subtype name appearing as an operand in expression
6996 -- Allow use of subtype if it is a concurrent type where we are
6997 -- currently inside the body. This will eventually be expanded into a
6998 -- call to Self (for tasks) or _object (for protected objects). Any
6999 -- other use of a subtype is invalid.
7003 then
7006 -- Any other use is an error
7008 else
7009 Error_Msg_N
7013 -- Check discriminant use if entity is discriminant in current scope,
7014 -- i.e. discriminant of record or concurrent type currently being
7015 -- analyzed. Uses in corresponding body are unrestricted.
7020 then
7023 -- A parameterless generic function cannot appear in a context that
7024 -- requires resolution.
7035 then
7038 -- In all other cases, just do the possible static evaluation
7040 else
7041 -- A deferred constant that appears in an expression must have a
7042 -- completion, unless it has been removed by in-place expansion of
7043 -- an aggregate.
7049 and then not In_Spec_Expression
7051 then
7055 then
7057 else
7058 Error_Msg_N (
7068 -- When the entity appears in a parameter association, retrieve the
7069 -- related subprogram call.
7075 -- The following checks are only relevant when SPARK_Mode is on as they
7076 -- are not standard Ada legality rules. An effectively volatile object
7077 -- subject to enabled properties Async_Writers or Effective_Reads must
7078 -- appear in a specific context.
7083 and then
7086 then
7087 -- The effectively volatile objects appears in a "non-interfering
7088 -- context" as defined in SPARK RM 7.1.3(13).
7093 -- Assume that references to effectively volatile objects that appear
7094 -- as actual parameters in a procedure call are always legal. A full
7095 -- legality check is done when the actuals are resolved.
7100 -- Otherwise the context causes a side effect with respect to the
7101 -- effectively volatile object.
7103 else
7104 SPARK_Msg_N
7110 -- A Ghost entity must appear in a specific context
7117 -------------------
7118 -- Resolve_Entry --
7119 -------------------
7131 -- If the bounds of the entry family being called depend on task
7132 -- discriminants, build a new index subtype where a discriminant is
7133 -- replaced with the value of the discriminant of the target task.
7134 -- The target task is the prefix of the entry name in the call.
7136 -----------------------
7137 -- Actual_Index_Type --
7138 -----------------------
7148 -- If the bound is given by a discriminant, replace with a reference
7149 -- to the discriminant of the same name in the target task. If the
7150 -- entry name is the target of a requeue statement and the entry is
7151 -- in the current protected object, the bound to be used is the
7152 -- discriminal of the object (see Apply_Range_Checks for details of
7153 -- the transformation).
7155 -----------------------------
7156 -- Actual_Discriminant_Ref --
7157 -----------------------------
7163 begin
7168 then
7174 then
7175 -- Note: here Bound denotes a discriminant of the corresponding
7176 -- record type tskV, whose discriminal is a formal of the
7177 -- init-proc tskVIP. What we want is the body discriminal,
7178 -- which is associated to the discriminant of the original
7179 -- concurrent type tsk.
7181 return New_Occurrence_Of
7184 else
7185 Ref :=
7195 -- Start of processing for Actual_Index_Type
7197 begin
7200 then
7203 else
7217 -- Start of processing of Resolve_Entry
7219 begin
7220 -- Find name of entry being called, and resolve prefix of name with its
7221 -- own type. The prefix can be overloaded, and the name and signature of
7222 -- the entry must be taken into account.
7226 -- Case of dealing with entry family within the current tasks
7230 else
7236 -- Entry call to an entry (or entry family) in the current task. This
7237 -- is legal even though the task will deadlock. Rewrite as call to
7238 -- current task.
7240 -- This can also be a call to an entry in an enclosing task. If this
7241 -- is a single task, we have to retrieve its name, because the scope
7242 -- of the entry is the task type, not the object. If the enclosing
7243 -- task is a task type, the identity of the task is given by its own
7244 -- self variable.
7246 -- Finally this can be a requeue on an entry of the same task or
7247 -- protected object.
7254 then
7255 -- S is an enclosing task or protected object. The concurrent
7256 -- declaration has been converted into a type declaration, and
7257 -- the object itself has an object declaration that follows
7258 -- the type in the same declarative part.
7270 -- Call to current task. Will be transformed into call to Self
7277 New_N :=
7280 Selector_Name =>
7287 then
7288 -- Use the entry name (which must be unique at this point) to find
7289 -- the prefix that returns the corresponding task/protected type.
7291 declare
7297 begin
7319 -- Up to this point the expression could have been the actual in a
7320 -- simple entry call, and be given by a named association.
7324 else
7330 ------------------------
7331 -- Resolve_Entry_Call --
7332 ------------------------
7344 begin
7345 -- We kill all checks here, because it does not seem worth the effort to
7346 -- do anything better, an entry call is a big operation.
7348 Kill_All_Checks;
7350 -- Processing of the name is similar for entry calls and protected
7351 -- operation calls. Once the entity is determined, we can complete
7352 -- the resolution of the actuals.
7354 -- The selector may be overloaded, in the case of a protected object
7355 -- with overloaded functions. The type of the context is used for
7356 -- resolution.
7361 then
7362 declare
7366 begin
7385 -- Simple entry call
7393 -- Call to member of entry family
7400 -- We cannot in general check the maximum depth of protected entry calls
7401 -- at compile time. But we can tell that any protected entry call at all
7402 -- violates a specified nesting depth of zero.
7408 -- Use context type to disambiguate a protected function that can be
7409 -- called without actuals and that returns an array type, and where the
7410 -- argument list may be an indexing of the returned value.
7415 and then
7421 and then
7422 Covers
7425 then
7426 declare
7429 begin
7430 Index_Node :=
7432 Prefix =>
7436 -- Since we are correcting a node classification error made by the
7437 -- parser, we call Replace rather than Rewrite.
7450 then
7451 -- Rewrite as call to the precondition wrapper, adding the task
7452 -- object to the list of actuals. If the call is to a member of an
7453 -- entry family, include the index as well.
7455 declare
7459 begin
7468 New_Call :=
7470 Name =>
7475 -- Preanalyze and resolve new call. Current procedure is called
7476 -- from Resolve_Call, after which expansion will take place.
7483 -- The operation name may have been overloaded. Order the actuals
7484 -- according to the formals of the resolved entity, and set the return
7485 -- type to that of the operation.
7496 -- Create a call reference to the entry
7504 -- Verify that a procedure call cannot masquerade as an entry
7505 -- call where an entry call is expected.
7510 then
7515 then
7520 then
7525 -- After resolution, entry calls and protected procedure calls are
7526 -- changed into entry calls, for expansion. The structure of the node
7527 -- does not change, so it can safely be done in place. Protected
7528 -- function calls must keep their structure because they are
7529 -- subexpressions.
7533 -- A protected operation that is not a function may modify the
7534 -- corresponding object, and cannot apply to a constant. If this
7535 -- is an internal call, the prefix is the type itself.
7541 then
7542 Error_Msg_N
7544 Entry_Name);
7558 -- Protected functions can return on the secondary stack, in which
7559 -- case we must trigger the transient scope mechanism.
7561 elsif Expander_Active
7563 then
7568 -------------------------
7569 -- Resolve_Equality_Op --
7570 -------------------------
7572 -- Both arguments must have the same type, and the boolean context does
7573 -- not participate in the resolution. The first pass verifies that the
7574 -- interpretation is not ambiguous, and the type of the left argument is
7575 -- correctly set, or is Any_Type in case of ambiguity. If both arguments
7576 -- are strings or aggregates, allocators, or Null, they are ambiguous even
7577 -- though they carry a single (universal) type. Diagnose this case here.
7585 -- The resolution rule for if expressions requires that each such must
7586 -- have a unique type. This means that if several dependent expressions
7587 -- are of a non-null anonymous access type, and the context does not
7588 -- impose an expected type (as can be the case in an equality operation)
7589 -- the expression must be rejected.
7592 -- Attempt to explain the nature of a redundant comparison with True. If
7593 -- the expression N is too complex, this routine issues a general error
7594 -- message.
7597 -- In the case of allocators and access attributes, the context must
7598 -- provide an indication of the specific access type to be used. If
7599 -- one operand is of such a "generic" access type, check whether there
7600 -- is a specific visible access type that has the same designated type.
7601 -- This is semantically dubious, and of no interest to any real code,
7602 -- but c48008a makes it all worthwhile.
7604 -------------------------
7605 -- Check_If_Expression --
7606 -------------------------
7612 begin
7619 then
7625 ------------------------
7626 -- Explain_Redundancy --
7627 ------------------------
7634 begin
7637 -- Strip the operand down to an entity
7639 loop
7642 else
7647 -- The construct denotes an entity
7652 -- Do not generate an error message when the comparison is done
7653 -- against the enumeration literal Standard.True.
7657 -- Build a customized error message
7684 -- The construct is too complex to disect, issue a general message
7686 else
7691 -----------------------------
7692 -- Find_Unique_Access_Type --
7693 -----------------------------
7700 begin
7702 E_Access_Attribute_Type)
7703 then
7707 E_Access_Attribute_Type)
7708 then
7710 else
7722 then
7735 -- Start of processing for Resolve_Equality_Op
7737 begin
7748 T = Any_Character
7749 then
7752 else
7761 then
7770 -- If expressions must have a single type, and if the context does
7771 -- not impose one the dependent expressions cannot be anonymous
7772 -- access types.
7774 -- Why no similar processing for case expressions???
7778 E_Anonymous_Access_Subprogram_Type)
7780 E_Anonymous_Access_Subprogram_Type)
7781 then
7789 -- In SPARK, equality operators = and /= for array types other than
7790 -- String are only defined when, for each index position, the
7791 -- operands have equal static bounds.
7795 -- Protect call to Matching_Static_Array_Bounds to avoid costly
7796 -- operation if not needed.
7804 then
7805 Check_SPARK_05_Restriction
7810 -- If the unique type is a class-wide type then it will be expanded
7811 -- into a dispatching call to the predefined primitive. Therefore we
7812 -- check here for potential violation of such restriction.
7818 if Warn_On_Redundant_Constructs
7823 then
7824 Error_Msg_N -- CODEFIX
7834 -- If this is an inequality, it may be the implicit inequality
7835 -- created for a user-defined operation, in which case the corres-
7836 -- ponding equality operation is not intrinsic, and the operation
7837 -- cannot be constant-folded. Else fold.
7842 or else Is_Intrinsic_Subprogram
7844 then
7850 then
7854 -- Ada 2005: If one operand is an anonymous access type, convert the
7855 -- other operand to it, to ensure that the underlying types match in
7856 -- the back-end. Same for access_to_subprogram, and the conversion
7857 -- verifies that the types are subtype conformant.
7859 -- We apply the same conversion in the case one of the operands is a
7860 -- private subtype of the type of the other.
7862 -- Why the Expander_Active test here ???
7864 if Expander_Active
7865 and then
7867 E_Anonymous_Access_Subprogram_Type)
7869 then
7889 ----------------------------------
7890 -- Resolve_Explicit_Dereference --
7891 ----------------------------------
7899 -- The candidate prefix type, if overloaded
7904 begin
7908 -- A useful optimization: check whether the dereference denotes an
7909 -- element of a container, and if so rewrite it as a call to the
7910 -- corresponding Element function.
7912 -- Disabled for now, on advice of ARG. A more restricted form of the
7913 -- predicate might be acceptable ???
7915 -- if Is_Container_Element (N) then
7916 -- return;
7917 -- end if;
7921 -- Use the context type to select the prefix that has the correct
7922 -- designated type. Keep the first match, which will be the inner-
7923 -- most.
7930 then
7935 -- Remove access types that do not match, but preserve access
7936 -- to subprogram interpretations, in case a further dereference
7937 -- is needed (see below).
7950 else
7951 -- If no interpretation covers the designated type of the prefix,
7952 -- this is the pathological case where not all implementations of
7953 -- the prefix allow the interpretation of the node as a call. Now
7954 -- that the expected type is known, Remove other interpretations
7955 -- from prefix, rewrite it as a call, and resolve again, so that
7956 -- the proper call node is generated.
7967 New_N :=
7969 Name =>
7980 -- If not overloaded, resolve P with its own type
7982 else
7990 -- If the designated type is a packed unconstrained array type, and the
7991 -- explicit dereference is not in the context of an attribute reference,
7992 -- then we must compute and set the actual subtype, since it is needed
7993 -- by Gigi. The reason we exclude the attribute case is that this is
7994 -- handled fine by Gigi, and in fact we use such attributes to build the
7995 -- actual subtype. We also exclude generated code (which builds actual
7996 -- subtypes directly if they are needed).
8003 then
8007 -- Note: No Eval processing is required for an explicit dereference,
8008 -- because such a name can never be static.
8012 -------------------------------------
8013 -- Resolve_Expression_With_Actions --
8014 -------------------------------------
8017 begin
8020 -- If N has no actions, and its expression has been constant folded,
8021 -- then rewrite N as just its expression. Note, we can't do this in
8022 -- the general case of Is_Empty_List (Actions (N)) as this would cause
8023 -- Expression (N) to be expanded again.
8027 then
8032 ----------------------------------
8033 -- Resolve_Generalized_Indexing --
8034 ----------------------------------
8042 begin
8043 -- In ASIS mode, propagate the information about the indices back to
8044 -- to the original indexing node. The generalized indexing is either
8045 -- a function call, or a dereference of one. The actuals include the
8046 -- prefix of the original node, which is the container expression.
8055 loop
8066 else
8072 ---------------------------
8073 -- Resolve_If_Expression --
8074 ---------------------------
8083 begin
8088 -- When the "then" expression is of a scalar subtype different from the
8089 -- result subtype, then insert a conversion to ensure the generation of
8090 -- a constraint check. The same is done for the else part below, again
8091 -- comparing subtypes rather than base types.
8095 then
8100 -- If ELSE expression present, just resolve using the determined type
8108 then
8113 -- If no ELSE expression is present, root type must be Standard.Boolean
8114 -- and we provide a Standard.True result converted to the appropriate
8115 -- Boolean type (in case it is a derived boolean type).
8118 Else_Expr :=
8123 else
8132 -------------------------------
8133 -- Resolve_Indexed_Component --
8134 -------------------------------
8142 begin
8150 -- Use the context type to select the prefix that yields the correct
8151 -- component type.
8153 declare
8160 begin
8167 and then
8168 Covers
8171 then
8180 else
8186 else
8197 else
8204 -- If prefix is access type, dereference to get real array type.
8205 -- Note: we do not apply an access check because the expander always
8206 -- introduces an explicit dereference, and the check will happen there.
8212 -- If name was overloaded, set component type correctly now
8213 -- If a misplaced call to an entry family (which has no index types)
8214 -- return. Error will be diagnosed from calling context.
8218 else
8225 -- The prefix may have resolved to a string literal, in which case its
8226 -- etype has a special representation. This is only possible currently
8227 -- if the prefix is a static concatenation, written in functional
8228 -- notation.
8233 else
8240 else
8251 -- Do not generate the warning on suspicious index if we are analyzing
8252 -- package Ada.Tags; otherwise we will report the warning with the
8253 -- Prims_Ptr field of the dispatch table.
8256 or else not
8258 Ada_Tags)
8259 then
8264 -- If the array type is atomic, and the component is not atomic, then
8265 -- this is worth a warning, since we have a situation where the access
8266 -- to the component may cause extra read/writes of the atomic array
8267 -- object, or partial word accesses, which could be unexpected.
8273 and then Has_Atomic_Components
8276 then
8284 -----------------------------
8285 -- Resolve_Integer_Literal --
8286 -----------------------------
8289 begin
8294 --------------------------------
8295 -- Resolve_Intrinsic_Operator --
8296 --------------------------------
8305 -- If the operand is a literal, it cannot be the expression in a
8306 -- conversion. Use a qualified expression instead.
8311 begin
8313 Res :=
8319 else
8326 -- Start of processing for Resolve_Intrinsic_Operator
8328 begin
8329 -- We must preserve the original entity in a generic setting, so that
8330 -- the legality of the operation can be verified in an instance.
8345 -- If the result or operand types are private, rewrite with unchecked
8346 -- conversions on the operands and the result, to expose the proper
8347 -- underlying numeric type.
8352 then
8354 -- Unchecked_Convert_To (Btyp, Left_Opnd (N));
8355 -- What on earth is this commented out fragment of code???
8359 else
8380 then
8381 -- Add explicit conversion where needed, and save interpretations in
8382 -- case operands are overloaded.
8389 else
8395 else
8405 else
8410 --------------------------------------
8411 -- Resolve_Intrinsic_Unary_Operator --
8412 --------------------------------------
8414 procedure Resolve_Intrinsic_Unary_Operator
8417 is
8422 begin
8441 else
8446 ------------------------
8447 -- Resolve_Logical_Op --
8448 ------------------------
8453 begin
8456 -- Predefined operations on scalar types yield the base type. On the
8457 -- other hand, logical operations on arrays yield the type of the
8458 -- arguments (and the context).
8462 else
8466 -- The following test is required because the operands of the operation
8467 -- may be literals, in which case the resulting type appears to be
8468 -- compatible with a signed integer type, when in fact it is compatible
8469 -- only with modular types. If the context itself is universal, the
8470 -- operation is illegal.
8478 Error_Msg_N
8486 then
8490 -- Replace AND by AND THEN, or OR by OR ELSE, if Short_Circuit_And_Or
8491 -- is active and the result type is standard Boolean (do not mess with
8492 -- ops that return a nonstandard Boolean type, because something strange
8493 -- is going on).
8495 -- Note: you might expect this replacement to be done during expansion,
8496 -- but that doesn't work, because when the pragma Short_Circuit_And_Or
8497 -- is used, no part of the right operand of an "and" or "or" operator
8498 -- should be executed if the left operand would short-circuit the
8499 -- evaluation of the corresponding "and then" or "or else". If we left
8500 -- the replacement to expansion time, then run-time checks associated
8501 -- with such operands would be evaluated unconditionally, due to being
8502 -- before the condition prior to the rewriting as short-circuit forms
8503 -- during expansion.
8505 if Short_Circuit_And_Or
8508 then
8516 -- Case of OR changed to OR ELSE
8518 else
8526 -- Return now, since analysis of the rewritten ops will take care of
8527 -- other reference bookkeeping and expression folding.
8542 -- In SPARK, logical operations AND, OR and XOR for arrays are defined
8543 -- only when both operands have same static lower and higher bounds. Of
8544 -- course the types have to match, so only check if operands are
8545 -- compatible and the node itself has no errors.
8549 then
8550 declare
8554 begin
8555 -- Protect call to Matching_Static_Array_Bounds to avoid costly
8556 -- operation if not needed.
8563 then
8564 Check_SPARK_05_Restriction
8573 ---------------------------
8574 -- Resolve_Membership_Op --
8575 ---------------------------
8577 -- The context can only be a boolean type, and does not determine the
8578 -- arguments. Arguments should be unambiguous, but the preference rule for
8579 -- universal types applies.
8589 -- Analysis has determined a unique type for the left operand. Use it to
8590 -- resolve the disjuncts.
8592 ----------------------------
8593 -- Resolve_Set_Membership --
8594 ----------------------------
8600 begin
8606 -- Alternative is an expression, a range
8607 -- or a subtype mark.
8611 then
8618 -- Check for duplicates for discrete case
8621 declare
8630 begin
8631 -- Loop checking duplicates. This is quadratic, but giant sets
8632 -- are unlikely in this context so it's a reasonable choice.
8639 N_Character_Literal)
8641 then
8659 -- Start of processing for Resolve_Membership_Op
8661 begin
8667 Resolve_Set_Membership;
8671 and then
8673 or else
8676 then
8679 -- Ada 2005 (AI-251): Support the following case:
8681 -- type I is interface;
8682 -- type T is tagged ...
8684 -- function Test (O : I'Class) is
8685 -- begin
8686 -- return O in T'Class.
8687 -- end Test;
8689 -- In this case we have nothing else to do. The membership test will be
8690 -- done at run time.
8697 then
8699 else
8703 -- If mixed-mode operations are present and operands are all literal,
8704 -- the only interpretation involves Duration, which is probably not
8705 -- the intention of the programmer.
8720 then
8726 else
8731 -- Here after resolving membership operation
8739 ------------------
8740 -- Resolve_Null --
8741 ------------------
8746 begin
8747 -- Handle restriction against anonymous null access values This
8748 -- restriction can be turned off using -gnatdj.
8750 -- Ada 2005 (AI-231): Remove restriction
8753 and then not Debug_Flag_J
8756 then
8757 -- In the common case of a call which uses an explicitly null value
8758 -- for an access parameter, give specialized error message.
8761 Error_Msg_N
8764 -- Standard message for all other cases (are there any?)
8766 else
8767 Error_Msg_N
8772 -- Ada 2005 (AI-231): Generate the null-excluding check in case of
8773 -- assignment to a null-excluding object
8778 then
8780 Insert_Action
8785 else
8792 -- In a distributed context, null for a remote access to subprogram may
8793 -- need to be replaced with a special record aggregate. In this case,
8794 -- return after having done the transformation.
8799 then
8803 -- The null literal takes its type from the context
8808 -----------------------
8809 -- Resolve_Op_Concat --
8810 -----------------------
8814 -- We wish to avoid deep recursion, because concatenations are often
8815 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
8816 -- operands nonrecursively until we find something that is not a simple
8817 -- concatenation (A in this case). We resolve that, and then walk back
8818 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
8819 -- to do the rest of the work at each level. The Parent pointers allow
8820 -- us to avoid recursion, and thus avoid running out of memory. See also
8821 -- Sem_Ch4.Analyze_Concatenation, where a similar approach is used.
8826 begin
8827 -- The following code is equivalent to:
8829 -- Resolve_Op_Concat_First (NN, Typ);
8830 -- Resolve_Op_Concat_Arg (N, ...);
8831 -- Resolve_Op_Concat_Rest (N, Typ);
8833 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
8834 -- operand is a concatenation.
8836 -- Walk down left operands
8838 loop
8847 -- Now (given the above example) NN is A&B and Op1 is A
8849 -- First resolve Op1 ...
8853 -- ... then walk NN back up until we reach N (where we started), calling
8854 -- Resolve_Op_Concat_Rest along the way.
8856 loop
8863 Check_SPARK_05_Restriction
8868 ---------------------------
8869 -- Resolve_Op_Concat_Arg --
8870 ---------------------------
8872 procedure Resolve_Op_Concat_Arg
8877 is
8881 begin
8883 if Is_Comp
8887 then
8889 else
8893 -- If both Array & Array and Array & Component are visible, there is a
8894 -- potential ambiguity that must be reported.
8899 then
8903 -- If the operation is user-defined and not overloaded use its
8904 -- profile. The operation may be a renaming, in which case it has
8905 -- been rewritten, and we want the original profile.
8910 then
8912 Etype
8916 -- Otherwise an aggregate may match both the array type and the
8917 -- component type.
8919 else
8924 else
8928 then
8929 declare
8934 begin
8939 -- Special-case the error message when the overloading is
8940 -- caused by a function that yields an array and can be
8941 -- called without parameters.
8946 Error_Msg_NE
8948 Error_Msg_NE
8952 else
8960 or else
8962 then
8963 Error_Msg_N -- CODEFIX
8981 else
8986 else
8990 -- Concatenation is restricted in SPARK: each operand must be either a
8991 -- string literal, the name of a string constant, a static character or
8992 -- string expression, or another concatenation. Arg cannot be a
8993 -- concatenation here as callers of Resolve_Op_Concat_Arg call it
8994 -- separately on each final operand, past concatenation operations.
8998 Check_SPARK_05_Restriction
9006 then
9007 Check_SPARK_05_Restriction
9011 -- Do not issue error on an operand that is neither a character nor a
9012 -- string, as the error is issued in Resolve_Op_Concat.
9014 else
9021 -----------------------------
9022 -- Resolve_Op_Concat_First --
9023 -----------------------------
9030 begin
9031 -- The parser folds an enormous sequence of concatenations of string
9032 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
9033 -- in the right operand. If the expression resolves to a predefined "&"
9034 -- operator, all is well. Otherwise, the parser's folding is wrong, so
9035 -- we give an error. See P_Simple_Expression in Par.Ch4.
9040 then
9055 ----------------------------
9056 -- Resolve_Op_Concat_Rest --
9057 ----------------------------
9063 begin
9072 -- If this is not a static concatenation, but the result is a string
9073 -- type (and not an array of strings) ensure that static string operands
9074 -- have their subtypes properly constructed.
9078 then
9084 ----------------------
9085 -- Resolve_Op_Expon --
9086 ----------------------
9091 begin
9092 -- Catch attempts to do fixed-point exponentiation with universal
9093 -- operands, which is a case where the illegality is not caught during
9094 -- normal operator analysis. This is not done in preanalysis mode
9095 -- since the tree is not fully decorated during preanalysis.
9106 then
9116 then
9123 then
9127 -- We do the resolution using the base type, because intermediate values
9128 -- in expressions are always of the base type, not a subtype of it.
9133 -- For integer types, right argument must be in Natural range
9148 -- Evaluate the exponentiation operator for dimensioned type
9151 else
9155 -- Set overflow checking bit. Much cleverer code needed here eventually
9156 -- and perhaps the Resolve routines should be separated for the various
9157 -- arithmetic operations, since they will need different processing. ???
9166 --------------------
9167 -- Resolve_Op_Not --
9168 --------------------
9174 -- This function determines if the parent node is a boolean operator or
9175 -- operation (comparison op, membership test, or short circuit form) and
9176 -- the not in question is the left operand of this operation. Note that
9177 -- if the not is in parens, then false is returned.
9179 -----------------------
9180 -- Parent_Is_Boolean --
9181 -----------------------
9184 begin
9188 else
9190 when N_Op_And |
9191 N_Op_Eq |
9192 N_Op_Ge |
9193 N_Op_Gt |
9194 N_Op_Le |
9195 N_Op_Lt |
9196 N_Op_Ne |
9197 N_Op_Or |
9198 N_Op_Xor |
9199 N_In |
9200 N_Not_In |
9201 N_And_Then |
9202 N_Or_Else =>
9212 -- Start of processing for Resolve_Op_Not
9214 begin
9215 -- Predefined operations on scalar types yield the base type. On the
9216 -- other hand, logical operations on arrays yield the type of the
9217 -- arguments (and the context).
9221 else
9225 -- Straightforward case of incorrect arguments
9232 -- Special case of probable missing parens
9236 Error_Msg_N
9239 else
9240 Error_Msg_N
9247 -- OK resolution of NOT
9249 else
9250 -- Warn if non-boolean types involved. This is a case like not a < b
9251 -- where a and b are modular, where we will get (not a) < b and most
9252 -- likely not (a < b) was intended.
9254 if Warn_On_Questionable_Missing_Parens
9256 and then Parent_Is_Boolean
9257 then
9261 -- Warn on double negation if checking redundant constructs
9263 if Warn_On_Redundant_Constructs
9268 then
9272 -- Complete resolution and evaluation of NOT
9282 -----------------------------
9283 -- Resolve_Operator_Symbol --
9284 -----------------------------
9286 -- Nothing to be done, all resolved already
9292 begin
9296 ----------------------------------
9297 -- Resolve_Qualified_Expression --
9298 ----------------------------------
9306 begin
9309 -- Protect call to Matching_Static_Array_Bounds to avoid costly
9310 -- operation if not needed.
9317 then
9318 Check_SPARK_05_Restriction
9322 -- A qualified expression requires an exact match of the type, class-
9323 -- wide matching is not allowed. However, if the qualifying type is
9324 -- specific and the expression has a class-wide type, it may still be
9325 -- okay, since it can be the result of the expansion of a call to a
9326 -- dispatching function, so we also have to check class-wideness of the
9327 -- type of the expression's original node.
9330 or else
9334 then
9338 -- If the target type is unconstrained, then we reset the type of the
9339 -- result from the type of the expression. For other cases, the actual
9340 -- subtype of the expression is the target type.
9344 then
9351 -- If we still have a qualified expression after the static evaluation,
9352 -- then apply a scalar range check if needed. The reason that we do this
9353 -- after the Eval call is that otherwise, the application of the range
9354 -- check may convert an illegal static expression and result in warning
9355 -- rather than giving an error (e.g Integer'(Integer'Last + 1)).
9362 ------------------------------
9363 -- Resolve_Raise_Expression --
9364 ------------------------------
9367 begin
9371 else
9376 -------------------
9377 -- Resolve_Range --
9378 -------------------
9385 -- Returns True if N is of the form X'First .. X'Last where X is the
9386 -- same entity for both attributes.
9388 --------------------
9389 -- First_Last_Ref --
9390 --------------------
9396 begin
9401 then
9402 declare
9405 begin
9409 then
9418 -- Start of processing for Resolve_Range
9420 begin
9425 -- Check for inappropriate range on unordered enumeration type
9429 -- Exclude X'First .. X'Last if X is the same entity for both
9431 and then not First_Last_Ref
9432 then
9434 Error_Msg_NE
9441 -- We have to check the bounds for being within the base range as
9442 -- required for a non-static context. Normally this is automatic and
9443 -- done as part of evaluating expressions, but the N_Range node is an
9444 -- exception, since in GNAT we consider this node to be a subexpression,
9445 -- even though in Ada it is not. The circuit in Sem_Eval could check for
9446 -- this, but that would put the test on the main evaluation path for
9447 -- expressions.
9452 -- Check for an ambiguous range over character literals. This will
9453 -- happen with a membership test involving only literals.
9461 -- If bounds are static, constant-fold them, so size computations are
9462 -- identical between front-end and back-end. Do not perform this
9463 -- transformation while analyzing generic units, as type information
9464 -- would be lost when reanalyzing the constant node in the instance.
9477 --------------------------
9478 -- Resolve_Real_Literal --
9479 --------------------------
9484 begin
9485 -- Special processing for fixed-point literals to make sure that the
9486 -- value is an exact multiple of small where this is required. We skip
9487 -- this for the universal real case, and also for generic types.
9493 then
9494 declare
9501 begin
9502 -- Case of literal is not an exact multiple of the Small
9506 -- For a source program literal for a decimal fixed-point type,
9507 -- this is statically illegal (RM 4.9(36)).
9512 then
9516 -- Generate a warning if literal from source
9519 and then Warn_On_Bad_Fixed_Value
9520 then
9521 Error_Msg_N
9523 N);
9526 -- Replace literal by a value that is the exact representation
9527 -- of a value of the type, i.e. a multiple of the small value,
9528 -- by truncation, since Machine_Rounds is false for all GNAT
9529 -- fixed-point types (RM 4.9(38)).
9539 -- In all cases, set the corresponding integer field
9545 -- Now replace the actual type by the expected type as usual
9551 -----------------------
9552 -- Resolve_Reference --
9553 -----------------------
9558 begin
9559 -- Replace general access with specific type
9567 -- If we are taking the reference of a volatile entity, then treat it as
9568 -- a potential modification of this entity. This is too conservative,
9569 -- but necessary because remove side effects can cause transformations
9570 -- of normal assignments into reference sequences that otherwise fail to
9571 -- notice the modification.
9578 --------------------------------
9579 -- Resolve_Selected_Component --
9580 --------------------------------
9595 -- Check whether this is the initialization of a component within an
9596 -- init proc (by assignment or call to another init proc). If true,
9597 -- there is no need for a discriminant check.
9599 --------------------
9600 -- Init_Component --
9601 --------------------
9604 begin
9605 return Inside_Init_Proc
9611 -- Start of processing for Resolve_Selected_Component
9613 begin
9616 -- Use the context type to select the prefix that has a selector
9617 -- of the correct name and type.
9625 else
9629 -- Locate selected component. For a private prefix the selector
9630 -- can denote a discriminant.
9634 -- The visible components of a class-wide type are those of
9635 -- the root type.
9645 then
9652 else
9656 Error_Msg_N
9661 else
9664 -- There may be an implicit dereference. Retrieve
9665 -- designated record type.
9669 else
9675 -- Resolution chooses the new interpretation.
9676 -- Find the component with the right name.
9681 loop
9698 -- There must be a legal interpretation at this point
9705 else
9706 -- Resolve prefix with its type
9711 -- Generate cross-reference. We needed to wait until full overloading
9712 -- resolution was complete to do this, since otherwise we can't tell if
9713 -- we are an lvalue or not.
9717 else
9721 -- If prefix is an access type, the node will be transformed into an
9722 -- explicit dereference during expansion. The type of the node is the
9723 -- designated type of that of the prefix.
9728 else
9732 -- Set flag for expander if discriminant check required
9739 and then not Init_Component
9740 then
9748 -- If the prefix is a record conversion, this may be a renamed
9749 -- discriminant whose bounds differ from those of the original
9750 -- one, so we must ensure that a range check is performed.
9755 then
9759 -- Note: No Eval processing is required, because the prefix is of a
9760 -- record type, or protected type, and neither can possibly be static.
9762 -- If the record type is atomic, and the component is non-atomic, then
9763 -- this is worth a warning, since we have a situation where the access
9764 -- to the component may cause extra read/writes of the atomic array
9765 -- object, or partial word accesses, both of which may be unexpected.
9771 then
9772 Error_Msg_N
9775 Error_Msg_N
9783 -------------------
9784 -- Resolve_Shift --
9785 -------------------
9792 begin
9793 -- We do the resolution using the base type, because intermediate values
9794 -- in expressions always are of the base type, not a subtype of it.
9807 ---------------------------
9808 -- Resolve_Short_Circuit --
9809 ---------------------------
9816 begin
9817 -- Ensure all actions associated with the left operand (e.g.
9818 -- finalization of transient controlled objects) are fully evaluated
9819 -- locally within an expression with actions. This is particularly
9820 -- helpful for coverage analysis. However this should not happen in
9821 -- generics.
9824 declare
9826 begin
9834 -- Set Comes_From_Source on L to preserve warnings for unset
9835 -- reference.
9844 -- Check for issuing warning for always False assert/check, this happens
9845 -- when assertions are turned off, in which case the pragma Assert/Check
9846 -- was transformed into:
9848 -- if False and then <condition> then ...
9850 -- and we detect this pattern
9852 if Warn_On_Assertion_Failure
9859 then
9860 declare
9863 begin
9864 -- Special handling of Asssert pragma
9868 then
9869 declare
9871 Original_Node
9872 (Expression
9875 begin
9876 -- Don't warn if original condition is explicit False,
9877 -- since obviously the failure is expected in this case.
9881 then
9884 -- Issue warning. We do not want the deletion of the
9885 -- IF/AND-THEN to take this message with it. We achieve this
9886 -- by making sure that the expanded code points to the Sloc
9887 -- of the expression, not the original pragma.
9889 else
9890 -- Note: Use Error_Msg_F here rather than Error_Msg_N.
9891 -- The source location of the expression is not usually
9892 -- the best choice here. For example, it gets located on
9893 -- the last AND keyword in a chain of boolean expressiond
9894 -- AND'ed together. It is best to put the message on the
9895 -- first character of the assertion, which is the effect
9896 -- of the First_Node call here.
9898 Error_Msg_F
9900 Expression
9905 -- Similar processing for Check pragma
9909 then
9910 -- Don't want to warn if original condition is explicit False
9912 declare
9914 Original_Node
9915 (Expression
9917 begin
9920 then
9923 -- Post warning
9925 else
9926 -- Again use Error_Msg_F rather than Error_Msg_N, see
9927 -- comment above for an explanation of why we do this.
9929 Error_Msg_F
9931 Expression
9939 -- Continue with processing of short circuit
9948 -------------------
9949 -- Resolve_Slice --
9950 -------------------
9959 begin
9962 -- Use the context type to select the prefix that yields the correct
9963 -- array type.
9965 declare
9972 begin
9980 then
9988 else
9993 else
10004 else
10014 -- If the prefix is an access to an unconstrained array, we must use
10015 -- the actual subtype of the object to perform the index checks. The
10016 -- object denoted by the prefix is implicit in the node, so we build
10017 -- an explicit representation for it in order to compute the actual
10018 -- subtype.
10023 declare
10027 begin
10038 then
10041 -- If the name is a selected component that depends on discriminants,
10042 -- build an actual subtype for it. This can happen only when the name
10043 -- itself is overloaded; otherwise the actual subtype is created when
10044 -- the selected component is analyzed.
10047 and then Full_Analysis
10049 then
10050 declare
10053 begin
10058 -- Maybe this should just be "else", instead of checking for the
10059 -- specific case of slice??? This is needed for the case where the
10060 -- prefix is an Image attribute, which gets expanded to a slice, and so
10061 -- has a constrained subtype which we want to use for the slice range
10062 -- check applied below (the range check won't get done if the
10063 -- unconstrained subtype of the 'Image is used).
10069 -- Obtain the type of the array index
10073 else
10077 -- If name was overloaded, set slice type correctly now
10081 -- Handle the generation of a range check that compares the array index
10082 -- against the discrete_range. The check is not applied to internally
10083 -- built nodes associated with the expansion of dispatch tables. Check
10084 -- that Ada.Tags has already been loaded to avoid extra dependencies on
10085 -- the unit.
10087 if Tagged_Type_Expansion
10093 then
10096 -- The discrete_range is specified by a subtype indication. Create a
10097 -- shallow copy and inherit the type, parent and source location from
10098 -- the discrete_range. This ensures that the range check is inserted
10099 -- relative to the slice and that the runtime exception points to the
10100 -- proper construct.
10109 -- The discrete_range is a regular range. Resolve the bounds and remove
10110 -- their side effects.
10112 else
10129 -- Check bad use of type with predicates
10131 declare
10134 begin
10137 then
10139 else
10144 Bad_Predicated_Subtype_Use
10149 -- Otherwise here is where we check suspicious indexes
10160 ----------------------------
10161 -- Resolve_String_Literal --
10162 ----------------------------
10173 begin
10174 -- For a string appearing in a concatenation, defer creation of the
10175 -- string_literal_subtype until the end of the resolution of the
10176 -- concatenation, because the literal may be constant-folded away. This
10177 -- is a useful optimization for long concatenation expressions.
10179 -- If the string is an aggregate built for a single character (which
10180 -- happens in a non-static context) or a is null string to which special
10181 -- checks may apply, we build the subtype. Wide strings must also get a
10182 -- string subtype if they come from a one character aggregate. Strings
10183 -- generated by attributes might be static, but it is often hard to
10184 -- determine whether the enclosing context is static, so we generate
10185 -- subtypes for them as well, thus losing some rarer optimizations ???
10186 -- Same for strings that come from a static conversion.
10188 Need_Check :=
10197 -- If the resolving type is itself a string literal subtype, we can just
10198 -- reuse it, since there is no point in creating another.
10204 and then not Need_Check
10206 N_Attribute_Reference,
10207 N_Qualified_Expression,
10208 N_Type_Conversion)
10209 then
10212 -- Do not generate a string literal subtype for the default expression
10213 -- of a formal parameter in GNATprove mode. This is because the string
10214 -- subtype is associated with the freezing actions of the subprogram,
10215 -- however freezing is disabled in GNATprove mode and as a result the
10216 -- subtype is unavailable.
10218 elsif GNATprove_Mode
10220 then
10223 -- Otherwise we must create a string literal subtype. Note that the
10224 -- whole idea of string literal subtypes is simply to avoid the need
10225 -- for building a full fledged array subtype for each literal.
10227 else
10233 or else Need_Check
10234 then
10241 then
10247 -- The validity of a null string has been checked in the call to
10248 -- Eval_String_Literal.
10253 -- Always accept string literal with component type Any_Character, which
10254 -- occurs in error situations and in comparisons of literals, both of
10255 -- which should accept all literals.
10260 -- If the type is bit-packed, then we always transform the string
10261 -- literal into a full fledged aggregate.
10266 -- Deal with cases of Wide_Wide_String, Wide_String, and String
10268 else
10269 -- For Standard.Wide_Wide_String, or any other type whose component
10270 -- type is Standard.Wide_Wide_Character, we know that all the
10271 -- characters in the string must be acceptable, since the parser
10272 -- accepted the characters as valid character literals.
10277 -- For the case of Standard.String, or any other type whose component
10278 -- type is Standard.Character, we must make sure that there are no
10279 -- wide characters in the string, i.e. that it is entirely composed
10280 -- of characters in range of type Character.
10282 -- If the string literal is the result of a static concatenation, the
10283 -- test has already been performed on the components, and need not be
10284 -- repeated.
10288 then
10292 -- If we are out of range, post error. This is one of the
10293 -- very few places that we place the flag in the middle of
10294 -- a token, right under the offending wide character. Not
10295 -- quite clear if this is right wrt wide character encoding
10296 -- sequences, but it's only an error message.
10298 Error_Msg
10305 -- For the case of Standard.Wide_String, or any other type whose
10306 -- component type is Standard.Wide_Character, we must make sure that
10307 -- there are no wide characters in the string, i.e. that it is
10308 -- entirely composed of characters in range of type Wide_Character.
10310 -- If the string literal is the result of a static concatenation,
10311 -- the test has already been performed on the components, and need
10312 -- not be repeated.
10316 then
10320 -- If we are out of range, post error. This is one of the
10321 -- very few places that we place the flag in the middle of
10322 -- a token, right under the offending wide character.
10324 -- This is not quite right, because characters in general
10325 -- will take more than one character position ???
10327 Error_Msg
10334 -- If the root type is not a standard character, then we will convert
10335 -- the string into an aggregate and will let the aggregate code do
10336 -- the checking. Standard Wide_Wide_Character is also OK here.
10338 else
10342 -- See if the component type of the array corresponding to the string
10343 -- has compile time known bounds. If yes we can directly check
10344 -- whether the evaluation of the string will raise constraint error.
10345 -- Otherwise we need to transform the string literal into the
10346 -- corresponding character aggregate and let the aggregate code do
10347 -- the checking.
10351 -- Check for the case of full range, where we are definitely OK
10357 -- Here the range is not the complete base type range, so check
10359 declare
10367 begin
10370 then
10376 then
10377 Apply_Compile_Time_Constraint_Error
10379 CE_Range_Check_Failed,
10390 -- If we got here we meed to transform the string literal into the
10391 -- equivalent qualified positional array aggregate. This is rather
10392 -- heavy artillery for this situation, but it is hard work to avoid.
10394 declare
10399 begin
10400 -- Build the character literals, we give them source locations that
10401 -- correspond to the string positions, which is a bit tricky given
10402 -- the possible presence of wide character escape sequences.
10416 -- Should we have a call to Skip_Wide here ???
10418 -- ??? else
10419 -- Skip_Wide (P);
10427 Expression =>
10434 -----------------------------
10435 -- Resolve_Type_Conversion --
10436 -----------------------------
10448 -- Set to False to suppress cases where we want to suppress the test
10449 -- for redundancy to avoid possible false positives on this warning.
10451 begin
10452 if not Conv_OK
10454 then
10458 -- If the Operand Etype is Universal_Fixed, then the conversion is
10459 -- never redundant. We need this check because by the time we have
10460 -- finished the rather complex transformation, the conversion looks
10461 -- redundant when it is not.
10466 -- If the operand is marked as Any_Fixed, then special processing is
10467 -- required. This is also a case where we suppress the test for a
10468 -- redundant conversion, since most certainly it is not redundant.
10473 -- Mixed-mode operation involving a literal. Context must be a fixed
10474 -- type which is applied to the literal subsequently.
10482 or else
10484 then
10485 -- Return if expression is ambiguous
10490 -- If nothing else, the available fixed type is Duration
10492 else
10496 -- Resolve the real operand with largest available precision
10500 else
10506 -- If the operand is a literal (it could be a non-static and
10507 -- illegal exponentiation) check whether the use of Duration
10508 -- is potentially inaccurate.
10513 then
10514 Error_Msg_N
10517 Error_Msg_N
10524 then
10527 else
10536 -- In SPARK, a type conversion between array types should be restricted
10537 -- to types which have matching static bounds.
10539 -- Protect call to Matching_Static_Array_Bounds to avoid costly
10540 -- operation if not needed.
10547 then
10548 Check_SPARK_05_Restriction
10552 -- In formal mode, the operand of an ancestor type conversion must be an
10553 -- object (not an expression).
10561 then
10567 -- Note: we do the Eval_Type_Conversion call before applying the
10568 -- required checks for a subtype conversion. This is important, since
10569 -- both are prepared under certain circumstances to change the type
10570 -- conversion to a constraint error node, but in the case of
10571 -- Eval_Type_Conversion this may reflect an illegality in the static
10572 -- case, and we would miss the illegality (getting only a warning
10573 -- message), if we applied the type conversion checks first.
10577 -- Even when evaluation is not possible, we may be able to simplify the
10578 -- conversion or its expression. This needs to be done before applying
10579 -- checks, since otherwise the checks may use the original expression
10580 -- and defeat the simplifications. This is specifically the case for
10581 -- elimination of the floating-point Truncation attribute in
10582 -- float-to-int conversions.
10586 -- If after evaluation we still have a type conversion, then we may need
10587 -- to apply checks required for a subtype conversion.
10589 -- Skip these type conversion checks if universal fixed operands
10590 -- operands involved, since range checks are handled separately for
10591 -- these cases (in the appropriate Expand routines in unit Exp_Fixd).
10597 then
10601 -- Issue warning for conversion of simple object to its own type. We
10602 -- have to test the original nodes, since they may have been rewritten
10603 -- by various optimizations.
10607 -- Here we test for a redundant conversion if the warning mode is
10608 -- active (and was not locally reset), and we have a type conversion
10609 -- from source not appearing in a generic instance.
10611 if Test_Redundant
10614 and then not In_Instance
10615 then
10619 -- If the node is part of a larger expression, the Target_Type
10620 -- may not be the original type of the node if the context is a
10621 -- condition. Recover original type to see if conversion is needed.
10625 then
10629 -- If we have an entity name, then give the warning if the entity
10630 -- is the right type, or if it is a loop parameter covered by the
10631 -- original type (that's needed because loop parameters have an
10632 -- odd subtype coming from the bounds).
10635 and then
10637 or else
10641 -- If not an entity, then type of expression must match
10644 then
10645 -- One more check, do not give warning if the analyzed conversion
10646 -- has an expression with non-static bounds, and the bounds of the
10647 -- target are static. This avoids junk warnings in cases where the
10648 -- conversion is necessary to establish staticness, for example in
10649 -- a case statement.
10653 then
10656 -- Finally, if this type conversion occurs in a context requiring
10657 -- a prefix, and the expression is a qualified expression then the
10658 -- type conversion is not redundant, since a qualified expression
10659 -- is not a prefix, whereas a type conversion is. For example, "X
10660 -- := T'(Funx(...)).Y;" is illegal because a selected component
10661 -- requires a prefix, but a type conversion makes it legal: "X :=
10662 -- T(T'(Funx(...))).Y;"
10664 -- In Ada 2012, a qualified expression is a name, so this idiom is
10665 -- no longer needed, but we still suppress the warning because it
10666 -- seems unfriendly for warnings to pop up when you switch to the
10667 -- newer language version.
10671 N_Indexed_Component,
10672 N_Selected_Component,
10673 N_Slice,
10674 N_Explicit_Dereference)
10675 then
10678 -- Never warn on conversion to Long_Long_Integer'Base since
10679 -- that is most likely an artifact of the extended overflow
10680 -- checking and comes from complex expanded code.
10685 -- Here we give the redundant conversion warning. If it is an
10686 -- entity, give the name of the entity in the message. If not,
10687 -- just mention the expression.
10689 -- Shoudn't we test Warn_On_Redundant_Constructs here ???
10691 else
10694 Error_Msg_NE -- CODEFIX
10697 else
10698 Error_Msg_NE
10706 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
10707 -- No need to perform any interface conversion if the type of the
10708 -- expression coincides with the target type.
10711 and then Expander_Active
10713 then
10714 declare
10718 begin
10719 -- If the type of the operand is a limited view, use the non-
10720 -- limited view when available.
10725 then
10741 -- Conversion from interface type
10745 -- Ada 2005 (AI-217): Handle entities from limited views
10749 Error_Msg_NE -- CODEFIX
10752 Error_Msg_N
10754 N);
10757 and then not
10760 then
10762 Error_Msg_NE -- CODEFIX
10765 Error_Msg_N
10767 N);
10769 else
10773 -- Conversion to interface type
10777 -- Handle subtypes
10784 or else Interface_Present_In_Ancestor
10787 then
10789 else
10792 Error_Msg_N
10800 -- Ada 2012: if target type has predicates, the result requires a
10801 -- predicate check. If the context is a call to another predicate
10802 -- check we must prevent infinite recursion.
10808 or else
10810 then
10813 else
10818 -- If at this stage we have a real to integer conversion, make sure
10819 -- that the Do_Range_Check flag is set, because such conversions in
10820 -- general need a range check. We only need this if expansion is off
10821 -- or we are in GNATProve mode.
10827 then
10832 ----------------------
10833 -- Resolve_Unary_Op --
10834 ----------------------
10843 begin
10846 Check_SPARK_05_Restriction
10850 -- Deal with intrinsic unary operators
10856 then
10861 -- Deal with universal cases
10864 or else
10866 then
10873 -- Generate warning for expressions like abs (x mod 2)
10875 if Warn_On_Redundant_Constructs
10877 then
10881 Error_Msg_N -- CODEFIX
10886 -- Deal with reference generation
10893 -- Set overflow checking bit. Much cleverer code needed here eventually
10894 -- and perhaps the Resolve routines should be separated for the various
10895 -- arithmetic operations, since they will need different processing ???
10903 -- Generate warning for expressions like -5 mod 3 for integers. No need
10904 -- to worry in the floating-point case, since parens do not affect the
10905 -- result so there is no point in giving in a warning.
10907 declare
10916 begin
10917 if Warn_On_Questionable_Missing_Parens
10921 then
10924 -- We are looking for cases where the right operand is not
10925 -- parenthesized, and is a binary operator, multiply, divide, or
10926 -- mod. These are the cases where the grouping can affect results.
10930 then
10931 -- For mod, we always give the warning, since the value is
10932 -- affected by the parenthesization (e.g. (-5) mod 315 /=
10933 -- -(5 mod 315)). But for the other cases, the only concern is
10934 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
10935 -- overflows, but (-2) * 64 does not). So we try to give the
10936 -- message only when overflow is possible.
10940 then
10945 else
10951 else
10955 -- Note that the test below is deliberately excluding the
10956 -- largest negative number, since that is a potentially
10957 -- troublesome case (e.g. -2 * x, where the result is the
10958 -- largest negative integer has an overflow with 2 * x).
10965 -- For the multiplication case, the only case we have to worry
10966 -- about is when (-a)*b is exactly the largest negative number
10967 -- so that -(a*b) can cause overflow. This can only happen if
10968 -- a is a power of 2, and more generally if any operand is a
10969 -- constant that is not a power of 2, then the parentheses
10970 -- cannot affect whether overflow occurs. We only bother to
10971 -- test the left most operand
10973 -- Loop looking at left operands for one that has known value
10980 -- Operand value of 0 or 1 skips warning
10985 -- Otherwise check power of 2, if power of 2, warn, if
10986 -- anything else, skip warning.
10988 else
10992 else
11001 -- Keep looking at left operands
11006 -- For rem or "/" we can only have a problematic situation
11007 -- if the divisor has a value of minus one or one. Otherwise
11008 -- overflow is impossible (divisor > 1) or we have a case of
11009 -- division by zero in any case.
11014 then
11018 -- If we fall through warning should be issued
11020 -- Shouldn't we test Warn_On_Questionable_Missing_Parens ???
11022 Error_Msg_N
11029 ----------------------------------
11030 -- Resolve_Unchecked_Expression --
11031 ----------------------------------
11033 procedure Resolve_Unchecked_Expression
11036 is
11037 begin
11042 ---------------------------------------
11043 -- Resolve_Unchecked_Type_Conversion --
11044 ---------------------------------------
11046 procedure Resolve_Unchecked_Type_Conversion
11049 is
11055 begin
11056 -- Resolve operand using its own type
11060 -- In an inlined context, the unchecked conversion may be applied
11061 -- to a literal, in which case its type is the type of the context.
11062 -- (In other contexts conversions cannot apply to literals).
11064 if In_Inlined_Body
11068 then
11076 ------------------------------
11077 -- Rewrite_Operator_As_Call --
11078 ------------------------------
11085 begin
11092 New_N :=
11103 ------------------------------
11104 -- Rewrite_Renamed_Operator --
11105 ------------------------------
11107 procedure Rewrite_Renamed_Operator
11111 is
11116 begin
11117 -- Do not perform this transformation within a pre/postcondition,
11118 -- because the expression will be re-analyzed, and the transformation
11119 -- might affect the visibility of the operator, e.g. in an instance.
11125 -- Rewrite the operator node using the real operator, not its renaming.
11126 -- Exclude user-defined intrinsic operations of the same name, which are
11127 -- treated separately and rewritten as calls.
11136 -- Indicate that both the original entity and its renaming are
11137 -- referenced at this point.
11148 -- If the context type is private, add the appropriate conversions so
11149 -- that the operator is applied to the full view. This is done in the
11150 -- routines that resolve intrinsic operators.
11154 then
11156 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
11157 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
11170 -- Operator renames a user-defined operator of the same name. Use the
11171 -- original operator in the node, which is the one Gigi knows about.
11178 -----------------------
11179 -- Set_Slice_Subtype --
11180 -----------------------
11182 -- Build an implicit subtype declaration to represent the type delivered by
11183 -- the slice. This is an abbreviated version of an array subtype. We define
11184 -- an index subtype for the slice, using either the subtype name or the
11185 -- discrete range of the slice. To be consistent with index usage elsewhere
11186 -- we create a list header to hold the single index. This list is not
11187 -- otherwise attached to the syntax tree.
11198 begin
11204 else
11205 -- We force the evaluation of a range. This is definitely needed in
11206 -- the renamed case, and seems safer to do unconditionally. Note in
11207 -- any case that since we will create and insert an Itype referring
11208 -- to this range, we must make sure any side effect removal actions
11209 -- are inserted before the Itype definition.
11215 -- If the discrete range is given by a subtype indication, the
11216 -- type of the slice is the base of the subtype mark.
11219 declare
11221 begin
11230 -- Take a new copy of Drange (where bounds have been rewritten to
11231 -- reference side-effect-free names). Using a separate tree ensures
11232 -- that further expansion (e.g. while rewriting a slice assignment
11233 -- into a FOR loop) does not attempt to remove side effects on the
11234 -- bounds again (which would cause the bounds in the index subtype
11235 -- definition to refer to temporaries before they are defined) (the
11236 -- reason is that some names are considered side effect free here
11237 -- for the subtype, but not in the context of a loop iteration
11238 -- scheme).
11259 -- The Etype of the existing Slice node is reset to this slice subtype.
11260 -- Its bounds are obtained from its first index.
11264 -- For packed slice subtypes, freeze immediately (except in the case of
11265 -- being in a "spec expression" where we never freeze when we first see
11266 -- the expression).
11271 -- For all other cases insert an itype reference in the slice's actions
11272 -- so that the itype is frozen at the proper place in the tree (i.e. at
11273 -- the point where actions for the slice are analyzed). Note that this
11274 -- is different from freezing the itype immediately, which might be
11275 -- premature (e.g. if the slice is within a transient scope). This needs
11276 -- to be done only if expansion is enabled.
11283 --------------------------------
11284 -- Set_String_Literal_Subtype --
11285 --------------------------------
11293 begin
11305 -- The low bound is set from the low bound of the corresponding index
11306 -- type. Note that we do not store the high bound in the string literal
11307 -- subtype, but it can be deduced if necessary from the length and the
11308 -- low bound.
11313 -- If the lower bound is not static we create a range for the string
11314 -- literal, using the index type and the known length of the literal.
11315 -- The index type is not necessarily Positive, so the upper bound is
11316 -- computed as T'Val (T'Pos (Low_Bound) + L - 1).
11318 else
11319 declare
11325 Prefix =>
11329 Left_Opnd =>
11332 Prefix =>
11334 Expressions =>
11336 Right_Opnd =>
11345 begin
11347 Set_String_Literal_Low_Bound
11350 else
11351 -- If the index type is an enumeration type, build bounds
11352 -- expression with attributes.
11354 Set_String_Literal_Low_Bound
11358 Prefix =>
11365 -- Build bona fide subtype for the string, and wrap it in an
11366 -- unchecked conversion, because the backend expects the
11367 -- String_Literal_Subtype to have a static lower bound.
11369 Index_Subtype :=
11376 -- In the context, the Index_Type may already have a constraint,
11377 -- so use common base type on string subtype. The base type may
11378 -- be used when generating attributes of the string, for example
11379 -- in the context of a slice assignment.
11404 ------------------------------
11405 -- Simplify_Type_Conversion --
11406 ------------------------------
11409 begin
11411 declare
11416 begin
11417 -- Special processing if the conversion is the expression of a
11418 -- Rounding or Truncation attribute reference. In this case we
11419 -- replace:
11421 -- ityp (ftyp'Rounding (x)) or ityp (ftyp'Truncation (x))
11423 -- by
11425 -- ityp (x)
11427 -- with the Float_Truncate flag set to False or True respectively,
11428 -- which is more efficient.
11431 and then
11437 Name_Truncation)
11438 then
11439 declare
11442 begin
11452 -----------------------------
11453 -- Unique_Fixed_Point_Type --
11454 -----------------------------
11463 -- Give error messages for true ambiguity. Messages are posted on node
11464 -- N, and entities T1, T2 are the possible interpretations.
11466 -----------------------
11467 -- Fixed_Point_Error --
11468 -----------------------
11471 begin
11477 -- Start of processing for Unique_Fixed_Point_Type
11479 begin
11480 -- The operations on Duration are visible, so Duration is always a
11481 -- possible interpretation.
11485 -- Look for fixed-point types in enclosing scopes
11494 then
11496 Fixed_Point_Error;
11498 else
11509 -- Look for visible fixed type declarations in the context
11520 then
11522 Fixed_Point_Error;
11524 else
11537 Error_Msg_NE
11539 else
11540 Error_Msg_NE
11547 ----------------------
11548 -- Valid_Conversion --
11549 ----------------------
11551 function Valid_Conversion
11556 is
11561 function Conversion_Check
11564 -- Little routine to post Msg if Valid is False, returns Valid value
11567 -- If Report_Errs, then calls Errout.Error_Msg_N with its arguments
11569 procedure Conversion_Error_NE
11573 -- If Report_Errs, then calls Errout.Error_Msg_NE with its arguments
11575 function Valid_Tagged_Conversion
11578 -- Specifically test for validity of tagged conversions
11581 -- Check index and component conformance, and accessibility levels if
11582 -- the component types are anonymous access types (Ada 2005).
11584 ----------------------
11585 -- Conversion_Check --
11586 ----------------------
11588 function Conversion_Check
11591 is
11592 begin
11593 if not Valid
11595 -- A generic unit has already been analyzed and we have verified
11596 -- that a particular conversion is OK in that context. Since the
11597 -- instance is reanalyzed without relying on the relationships
11598 -- established during the analysis of the generic, it is possible
11599 -- to end up with inconsistent views of private types. Do not emit
11600 -- the error message in such cases. The rest of the machinery in
11601 -- Valid_Conversion still ensures the proper compatibility of
11602 -- target and operand types.
11604 and then not In_Instance
11605 then
11612 ------------------------
11613 -- Conversion_Error_N --
11614 ------------------------
11617 begin
11623 -------------------------
11624 -- Conversion_Error_NE --
11625 -------------------------
11627 procedure Conversion_Error_NE
11631 is
11632 begin
11638 ----------------------------
11639 -- Valid_Array_Conversion --
11640 ----------------------------
11643 is
11658 begin
11659 -- Error if wrong number of dimensions
11661 if
11663 then
11664 Conversion_Error_N
11668 -- Number of dimensions matches
11670 else
11671 -- Loop through indexes of the two arrays
11679 -- Error if index types are incompatible
11685 then
11686 Conversion_Error_N
11688 Operand);
11696 -- If component types have same base type, all set
11701 -- Here if base types of components are not the same. The only
11702 -- time this is allowed is if we have anonymous access types.
11704 -- The conversion of arrays of anonymous access types can lead
11705 -- to dangling pointers. AI-392 formalizes the accessibility
11706 -- checks that must be applied to such conversions to prevent
11707 -- out-of-scope references.
11709 elsif Ekind_In
11711 E_Anonymous_Access_Subprogram_Type)
11713 and then
11715 then
11718 then
11721 Conversion_Error_N
11731 -- Conversion not allowed because of accessibility levels
11733 else
11734 Conversion_Error_N
11740 else
11744 -- All other cases where component base types do not match
11746 else
11747 Conversion_Error_N
11749 Operand);
11753 -- Check that component subtypes statically match. For numeric
11754 -- types this means that both must be either constrained or
11755 -- unconstrained. For enumeration types the bounds must match.
11756 -- All of this is checked in Subtypes_Statically_Match.
11758 if not Subtypes_Statically_Match
11760 then
11761 Conversion_Error_N
11770 -----------------------------
11771 -- Valid_Tagged_Conversion --
11772 -----------------------------
11774 function Valid_Tagged_Conversion
11777 is
11778 begin
11779 -- Upward conversions are allowed (RM 4.6(22))
11783 then
11786 -- Downward conversion are allowed if the operand is class-wide
11787 -- (RM 4.6(23)).
11791 then
11796 then
11797 return
11801 -- Ada 2005 (AI-251): The conversion to/from interface types is
11802 -- always valid
11807 -- If the operand is a class-wide type obtained through a limited_
11808 -- with clause, and the context includes the non-limited view, use
11809 -- it to determine whether the conversion is legal.
11815 then
11820 then
11823 else
11824 Conversion_Error_NE
11831 -- Start of processing for Valid_Conversion
11833 begin
11837 declare
11845 begin
11846 -- Remove procedure calls, which syntactically cannot appear in
11847 -- this context, but which cannot be removed by type checking,
11848 -- because the context does not impose a type.
11850 -- The node may be labelled overloaded, but still contain only one
11851 -- interpretation because others were discarded earlier. If this
11852 -- is the case, retain the single interpretation if legal.
11860 then
11861 -- More than one candidate interpretation is available
11869 -- When compiling for a system where Address is of a visible
11870 -- integer type, spurious ambiguities can be produced when
11871 -- arithmetic operations have a literal operand and return
11872 -- System.Address or a descendant of it. These ambiguities
11873 -- are usually resolved by the context, but for conversions
11874 -- there is no context type and the removal of the spurious
11875 -- operations must be done explicitly here.
11877 if not Address_Is_Private
11879 then
11904 Conversion_Error_N
11907 -- If the interpretation involves a standard operator, use
11908 -- the location of the type, which may be user-defined.
11912 else
11916 Conversion_Error_N -- CODEFIX
11921 else
11925 Conversion_Error_N -- CODEFIX
11937 -- Deal with conversion of integer type to address if the pragma
11938 -- Allow_Integer_Address is in effect. We convert the conversion to
11939 -- an unchecked conversion in this case and we are all done.
11947 -- If we are within a child unit, check whether the type of the
11948 -- expression has an ancestor in a parent unit, in which case it
11949 -- belongs to its derivation class even if the ancestor is private.
11950 -- See RM 7.3.1 (5.2/3).
11954 -- Numeric types
11958 -- A universal fixed expression can be converted to any numeric type
11963 -- Also no need to check when in an instance or inlined body, because
11964 -- the legality has been established when the template was analyzed.
11965 -- Furthermore, numeric conversions may occur where only a private
11966 -- view of the operand type is visible at the instantiation point.
11967 -- This results in a spurious error if we check that the operand type
11968 -- is a numeric type.
11970 -- Note: in a previous version of this unit, the following tests were
11971 -- applied only for generated code (Comes_From_Source set to False),
11972 -- but in fact the test is required for source code as well, since
11973 -- this situation can arise in source code.
11978 -- Otherwise we need the conversion check
11980 else
11981 return Conversion_Check
11983 or else
11989 -- Array types
11995 then
11996 Conversion_Error_N
12000 else
12004 -- Ada 2005 (AI-251): Anonymous access types where target references an
12005 -- interface type.
12008 E_Anonymous_Access_Type)
12010 then
12011 -- Check the static accessibility rule of 4.6(17). Note that the
12012 -- check is not enforced when within an instance body, since the
12013 -- RM requires such cases to be caught at run time.
12015 -- If the operand is a rewriting of an allocator no check is needed
12016 -- because there are no accessibility issues.
12024 then
12025 -- In an instance, this is a run-time check, but one we know
12026 -- will fail, so generate an appropriate warning. The raise
12027 -- will be generated by Expand_N_Type_Conversion.
12031 Conversion_Error_N
12033 Operand);
12036 else
12037 Conversion_Error_N
12039 Operand);
12043 -- Special accessibility checks are needed in the case of access
12044 -- discriminants declared for a limited type.
12048 then
12049 -- When the operand is a selected access discriminant the check
12050 -- needs to be made against the level of the object denoted by
12051 -- the prefix of the selected name (Object_Access_Level handles
12052 -- checking the prefix of the operand for this case).
12057 then
12058 -- In an instance, this is a run-time check, but one we know
12059 -- will fail, so generate an appropriate warning. The raise
12060 -- will be generated by Expand_N_Type_Conversion.
12064 Conversion_Error_N
12069 -- Real error if not in instance body
12071 else
12072 Conversion_Error_N
12079 -- The case of a reference to an access discriminant from
12080 -- within a limited type declaration (which will appear as
12081 -- a discriminal) is always illegal because the level of the
12082 -- discriminant is considered to be deeper than any (nameable)
12083 -- access type.
12087 and then
12090 then
12091 Conversion_Error_N
12093 Operand);
12101 -- General and anonymous access types
12104 E_Anonymous_Access_Type)
12105 and then
12106 Conversion_Check
12108 and then not
12110 E_Access_Protected_Subprogram_Type),
12112 then
12115 then
12116 Conversion_Error_N
12121 -- Check the static accessibility rule of 4.6(17). Note that the
12122 -- check is not enforced when within an instance body, since the RM
12123 -- requires such cases to be caught at run time.
12128 N_Object_Declaration
12129 then
12130 -- Ada 2012 (AI05-0149): Perform legality checking on implicit
12131 -- conversions from an anonymous access type to a named general
12132 -- access type. Such conversions are not allowed in the case of
12133 -- access parameters and stand-alone objects of an anonymous
12134 -- access type. The implicit conversion case is recognized by
12135 -- testing that Comes_From_Source is False and that it's been
12136 -- rewritten. The Comes_From_Source test isn't sufficient because
12137 -- nodes in inlined calls to predefined library routines can have
12138 -- Comes_From_Source set to False. (Is there a better way to test
12139 -- for implicit conversions???)
12146 then
12149 -- Implicit conversions aren't allowed for objects of an
12150 -- anonymous access type, since such objects have nonstatic
12151 -- levels in Ada 2012.
12154 N_Object_Declaration
12155 then
12156 Conversion_Error_N
12161 -- Implicit conversions aren't allowed for anonymous access
12162 -- parameters. The "not Is_Local_Anonymous_Access_Type" test
12163 -- is done to exclude anonymous access results.
12167 N_Function_Specification,
12168 N_Procedure_Specification)
12169 then
12170 Conversion_Error_N
12175 -- This is a case where there's an enclosing object whose
12176 -- to which the "statically deeper than" relationship does
12177 -- not apply (such as an access discriminant selected from
12178 -- a dereference of an access parameter).
12182 then
12183 Conversion_Error_N
12188 -- In other cases, the level of the operand's type must be
12189 -- statically less deep than that of the target type, else
12190 -- implicit conversion is disallowed (by RM12-8.6(27.1/3)).
12194 then
12195 Conversion_Error_N
12204 then
12205 -- In an instance, this is a run-time check, but one we know
12206 -- will fail, so generate an appropriate warning. The raise
12207 -- will be generated by Expand_N_Type_Conversion.
12211 Conversion_Error_N
12213 Operand);
12216 -- If not in an instance body, this is a real error
12218 else
12219 -- Avoid generation of spurious error message
12222 Conversion_Error_N
12224 Operand);
12230 -- Special accessibility checks are needed in the case of access
12231 -- discriminants declared for a limited type.
12235 then
12236 -- When the operand is a selected access discriminant the check
12237 -- needs to be made against the level of the object denoted by
12238 -- the prefix of the selected name (Object_Access_Level handles
12239 -- checking the prefix of the operand for this case).
12244 then
12245 -- In an instance, this is a run-time check, but one we know
12246 -- will fail, so generate an appropriate warning. The raise
12247 -- will be generated by Expand_N_Type_Conversion.
12251 Conversion_Error_N
12256 -- If not in an instance body, this is a real error
12258 else
12259 Conversion_Error_N
12266 -- The case of a reference to an access discriminant from
12267 -- within a limited type declaration (which will appear as
12268 -- a discriminal) is always illegal because the level of the
12269 -- discriminant is considered to be deeper than any (nameable)
12270 -- access type.
12273 and then
12276 then
12277 Conversion_Error_N
12279 Operand);
12285 -- In the presence of limited_with clauses we have to use non-limited
12286 -- views, if available.
12290 -- Helper function to handle limited views
12292 --------------------------
12293 -- Full_Designated_Type --
12294 --------------------------
12299 begin
12300 -- Handle the limited view of a type
12305 then
12307 else
12312 -- Local Declarations
12320 -- Start of processing for Check_Limited
12322 begin
12326 else
12328 Conversion_Error_NE
12333 -- Ada 2005 AI-384: legality rule is symmetric in both
12334 -- designated types. The conversion is legal (with possible
12335 -- constraint check) if either designated type is
12336 -- unconstrained.
12339 or else
12341 and then
12344 then
12345 -- Special case, if Value_Size has been used to make the
12346 -- sizes different, the conversion is not allowed even
12347 -- though the subtypes statically match.
12352 then
12353 Conversion_Error_NE
12356 Conversion_Error_NE
12361 -- Normal case where conversion is allowed
12363 else
12367 else
12368 Error_Msg_NE
12376 -- Access to subprogram types. If the operand is an access parameter,
12377 -- the type has a deeper accessibility that any master, and cannot be
12378 -- assigned. We must make an exception if the conversion is part of an
12379 -- assignment and the target is the return object of an extended return
12380 -- statement, because in that case the accessibility check takes place
12381 -- after the return.
12385 -- Note: this test of Opnd_Type is there to prevent entering this
12386 -- branch in the case of a remote access to subprogram type, which
12387 -- is internally represented as an E_Record_Type.
12390 then
12394 and then
12398 then
12399 Conversion_Error_N
12401 Operand);
12402 Conversion_Error_N
12405 Operand);
12407 Error_Msg_NE
12412 -- Check that the designated types are subtype conformant
12418 -- Check the static accessibility rule of 4.6(20)
12422 then
12423 Conversion_Error_N
12425 Operand);
12427 -- Check that if the operand type is declared in a generic body,
12428 -- then the target type must be declared within that same body
12429 -- (enforces last sentence of 4.6(20)).
12432 declare
12438 begin
12445 Conversion_Error_N
12454 -- Remote access to subprogram types
12458 then
12459 -- It is valid to convert from one RAS type to another provided
12460 -- that their specification statically match.
12462 -- Note: at this point, remote access to subprogram types have been
12463 -- expanded to their E_Record_Type representation, and we need to
12464 -- go back to the original access type definition using the
12465 -- Corresponding_Remote_Type attribute in order to check that the
12466 -- designated profiles match.
12471 Check_Subtype_Conformant
12474 Old_Id =>
12476 Err_Loc =>
12477 N);
12480 -- If it was legal in the generic, it's legal in the instance
12485 -- If both are tagged types, check legality of view conversions
12488 and then
12490 then
12493 -- Types derived from the same root type are convertible
12498 -- In an instance or an inlined body, there may be inconsistent views of
12499 -- the same type, or of types derived from a common root.
12502 and then
12505 then
12508 -- Special check for common access type error case
12512 then
12514 Conversion_Error_NE -- CODEFIX
12518 -- Here we have a real conversion error
12520 else
12521 Conversion_Error_NE