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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) 1992-2008, 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 ------------------------------------------------------------------------------
79 -----------------------
80 -- Local Subprograms --
81 -----------------------
83 -- Second pass (top-down) type checking and overload resolution procedures
84 -- Typ is the type required by context. These procedures propagate the
85 -- type information recursively to the descendants of N. If the node
86 -- is not overloaded, its Etype is established in the first pass. If
87 -- overloaded, the Resolve routines set the correct type. For arith.
88 -- operators, the Etype is the base type of the context.
90 -- Note that Resolve_Attribute is separated off in Sem_Attr
93 -- Enforce the restrictions on the use of discriminants when constraining
94 -- a component of a discriminated type (record or concurrent type).
97 -- Given a node for an operator associated with type T, check that
98 -- the operator is visible. Operators all of whose operands are
99 -- universal must be checked for visibility during resolution
100 -- because their type is not determinable based on their operands.
102 procedure Check_Fully_Declared_Prefix
105 -- Check that the type of the prefix of a dereference is not incomplete
108 -- Given a call node, N, which is known to occur immediately within the
109 -- subprogram being called, determines whether it is a detectable case of
110 -- an infinite recursion, and if so, outputs appropriate messages. Returns
111 -- True if an infinite recursion is detected, and False otherwise.
114 -- If the type of the object being initialized uses the secondary stack
115 -- directly or indirectly, create a transient scope for the call to the
116 -- init proc. This is because we do not create transient scopes for the
117 -- initialization of individual components within the init proc itself.
118 -- Could be optimized away perhaps?
121 -- Determine whether E is an access type declared by an access
122 -- declaration, and not an (anonymous) allocator type.
125 -- Utility to check whether the name in the call is a predefined
126 -- operator, in which case the call is made into an operator node.
127 -- An instance of an intrinsic conversion operation may be given
128 -- an operator name, but is not treated like an operator.
131 -- If a default expression in entry call N depends on the discriminants
132 -- of the task, it must be replaced with a reference to the discriminant
133 -- of the task being called.
135 procedure Resolve_Op_Concat_Arg
140 -- Internal procedure for Resolve_Op_Concat to resolve one operand of
141 -- concatenation operator. The operand is either of the array type or of
142 -- the component type. If the operand is an aggregate, and the component
143 -- type is composite, this is ambiguous if component type has aggregates.
146 -- Does the first part of the work of Resolve_Op_Concat
149 -- Does the "rest" of the work of Resolve_Op_Concat, after the left operand
150 -- has been resolved. See Resolve_Op_Concat for details.
185 function Operator_Kind
188 -- Utility to map the name of an operator into the corresponding Node. Used
189 -- by other node rewriting procedures.
192 -- Resolve actuals of call, and add default expressions for missing ones.
193 -- N is the Node_Id for the subprogram call, and Nam is the entity of the
194 -- called subprogram.
197 -- Called from Resolve_Call, when the prefix denotes an entry or element
198 -- of entry family. Actuals are resolved as for subprograms, and the node
199 -- is rebuilt as an entry call. Also called for protected operations. Typ
200 -- is the context type, which is used when the operation is a protected
201 -- function with no arguments, and the return value is indexed.
204 -- A call to a user-defined intrinsic operator is rewritten as a call
205 -- to the corresponding predefined operator, with suitable conversions.
208 -- Ditto, for unary operators (only arithmetic ones)
211 -- If an operator node resolves to a call to a user-defined operator,
212 -- rewrite the node as a function call.
214 procedure Make_Call_Into_Operator
218 -- Inverse transformation: if an operator is given in functional notation,
219 -- then after resolving the node, transform into an operator node, so
220 -- that operands are resolved properly. Recall that predefined operators
221 -- do not have a full signature and special resolution rules apply.
223 procedure Rewrite_Renamed_Operator
227 -- An operator can rename another, e.g. in an instantiation. In that
228 -- case, the proper operator node must be constructed and resolved.
231 -- The String_Literal_Subtype is built for all strings that are not
232 -- operands of a static concatenation operation. If the argument is
233 -- not a N_String_Literal node, then the call has no effect.
236 -- Build subtype of array type, with the range specified by the slice
239 -- Called after N has been resolved and evaluated, but before range checks
240 -- have been applied. Currently simplifies a combination of floating-point
241 -- to integer conversion and Truncation attribute.
244 -- A universal_fixed expression in an universal context is unambiguous
245 -- if there is only one applicable fixed point type. Determining whether
246 -- there is only one requires a search over all visible entities, and
247 -- happens only in very pathological cases (see 6115-006).
249 function Valid_Conversion
253 -- Verify legality rules given in 4.6 (8-23). Target is the target
254 -- type of the conversion, which may be an implicit conversion of
255 -- an actual parameter to an anonymous access type (in which case
256 -- N denotes the actual parameter and N = Operand).
258 -------------------------
259 -- Ambiguous_Character --
260 -------------------------
265 begin
269 -- First the ones in Standard
271 Error_Msg_N
273 Error_Msg_N
276 -- Include Wide_Wide_Character in Ada 2005 mode
279 Error_Msg_N
283 -- Now any other types that match
293 -------------------------
294 -- Analyze_And_Resolve --
295 -------------------------
298 begin
304 begin
309 -- Version withs check(s) suppressed
311 procedure Analyze_And_Resolve
315 is
318 begin
320 declare
322 begin
328 else
329 declare
332 begin
340 and then Scope_Is_Transient
341 then
342 -- This can only happen if a transient scope was created
343 -- for an inner expression, which will be removed upon
344 -- completion of the analysis of an enclosing construct.
345 -- The transient scope must have the suppress status of
346 -- the enclosing environment, not of this Analyze call.
349 Scope_Suppress;
353 procedure Analyze_And_Resolve
356 is
359 begin
361 declare
363 begin
369 else
370 declare
373 begin
381 and then Scope_Is_Transient
382 then
384 Scope_Suppress;
388 ----------------------------
389 -- Check_Discriminant_Use --
390 ----------------------------
398 begin
399 -- Any use in a spec-expression is legal
406 -- Discriminant cannot be used to constrain a scalar type
413 then
418 -- The following check catches the unusual case where
419 -- a discriminant appears within an index constraint
420 -- that is part of a larger expression within a constraint
421 -- on a component, e.g. "C : Int range 1 .. F (new A(1 .. D))".
422 -- For now we only check case of record components, and
423 -- note that a similar check should also apply in the
424 -- case of discriminant constraints below. ???
426 -- Note that the check for N_Subtype_Declaration below is to
427 -- detect the valid use of discriminants in the constraints of a
428 -- subtype declaration when this subtype declaration appears
429 -- inside the scope of a record type (which is syntactically
430 -- illegal, but which may be created as part of derived type
431 -- processing for records). See Sem_Ch3.Build_Derived_Record_Type
432 -- for more info.
436 and then not
438 and then
440 N_Subtype_Declaration)
442 then
443 Error_Msg_N
448 -- Detect a common beginner error:
450 -- type R (D : Positive := 100) is record
451 -- Name : String (1 .. D);
452 -- end record;
454 -- The default value causes an object of type R to be
455 -- allocated with room for Positive'Last characters.
457 declare
464 -- Return True if type T has a large enough range that
465 -- any array whose index type covered the whole range of
466 -- the type would likely raise Storage_Error.
468 ------------------------
469 -- Large_Storage_Type --
470 ------------------------
473 begin
474 return
475 T = Standard_Integer
476 or else
477 T = Standard_Positive
478 or else
482 begin
483 -- Check that the Disc has a large range
489 -- If the enclosing type is limited, we allocate only the
490 -- default value, not the maximum, and there is no need for
491 -- a warning.
497 -- Check that it is the high bound
501 then
505 -- Check the array allows a large range at this bound.
506 -- First find the array
520 -- Next, find the dimension
528 loop
537 -- Now, check the dimension has a large range
543 -- Warn about the danger
545 Error_Msg_N
555 -- Legal case is in index or discriminant constraint
558 N_Discriminant_Association)
559 then
561 Error_Msg_N
566 then
567 Error_Msg_N
573 -- Otherwise, context is an expression. It should not be within
574 -- (i.e. a subexpression of) a constraint for a component.
576 else
580 N_Subtype_Indication,
581 N_Entry_Declaration)
582 loop
588 -- If the discriminant is used in an expression that is a bound
589 -- of a scalar type, an Itype is created and the bounds are attached
590 -- to its range, not to the original subtype indication. Such use
591 -- is of course a double fault.
595 N_Derived_Type_Definition)
598 -- The constraint itself may be given by a subtype indication,
599 -- rather than by a more common discrete range.
602 and then
606 then
607 Error_Msg_N
613 --------------------------------
614 -- Check_For_Visible_Operator --
615 --------------------------------
618 begin
620 Error_Msg_NE
626 ----------------------------------
627 -- Check_Fully_Declared_Prefix --
628 ----------------------------------
630 procedure Check_Fully_Declared_Prefix
633 is
634 begin
635 -- Check that the designated type of the prefix of a dereference is
636 -- not an incomplete type. This cannot be done unconditionally, because
637 -- dereferences of private types are legal in default expressions. This
638 -- case is taken care of in Check_Fully_Declared, called below. There
639 -- are also 2005 cases where it is legal for the prefix to be unfrozen.
641 -- This consideration also applies to similar checks for allocators,
642 -- qualified expressions, and type conversions.
644 -- An additional exception concerns other per-object expressions that
645 -- are not directly related to component declarations, in particular
646 -- representation pragmas for tasks. These will be per-object
647 -- expressions if they depend on discriminants or some global entity.
648 -- If the task has access discriminants, the designated type may be
649 -- incomplete at the point the expression is resolved. This resolution
650 -- takes place within the body of the initialization procedure, where
651 -- the discriminant is replaced by its discriminal.
655 then
658 -- Ada 2005 (AI-326): Tagged incomplete types allowed. The wrong usages
659 -- are handled by Analyze_Access_Attribute, Analyze_Assignment,
660 -- Analyze_Object_Renaming, and Freeze_Entity.
665 E_Incomplete_Type
667 then
669 else
674 ------------------------------
675 -- Check_Infinite_Recursion --
676 ------------------------------
683 -- Check whether list of actuals is identical to list of formals
684 -- of called function (which is also the enclosing scope).
686 ------------------------
687 -- Same_Argument_List --
688 ------------------------
695 begin
698 else
707 then
718 -- Start of processing for Check_Infinite_Recursion
720 begin
721 -- Special case, if this is a procedure call and is a call to the
722 -- current procedure with the same argument list, then this is for
723 -- sure an infinite recursion and we insert a call to raise SE.
727 and then Same_Argument_List
728 then
729 declare
731 begin
735 then
746 -- If not that special case, search up tree, quitting if we reach a
747 -- construct (e.g. a conditional) that tells us that this is not a
748 -- case for an infinite recursion warning.
751 loop
755 N_And_Then,
756 N_If_Statement,
757 N_Case_Statement)
758 then
763 then
764 -- If the call is the expression of a return statement and the
765 -- actuals are identical to the formals, it's worth a warning.
766 -- However, we skip this if there is an immediately preceding
767 -- raise statement, since the call is never executed.
769 -- Furthermore, this corresponds to a common idiom:
771 -- function F (L : Thing) return Boolean is
772 -- begin
773 -- raise Program_Error;
774 -- return F (L);
775 -- end F;
777 -- for generating a stub function
780 and then Same_Argument_List
781 then
784 -- OK, return statement is in a statement list, look for raise
786 declare
789 begin
790 -- Skip past N_Freeze_Entity nodes generated by expansion
795 loop
799 -- If no raise statement, give warning
802 and then
810 else
821 -------------------------------
822 -- Check_Initialization_Call --
823 -------------------------------
829 -- Check whether the creation of an object of the type will involve
830 -- use of the secondary stack. If T is a record type, this is true
831 -- if the expression for some component uses the secondary stack, e.g.
832 -- through a call to a function that returns an unconstrained value.
833 -- False if T is controlled, because cleanups occur elsewhere.
835 -------------
836 -- Uses_SS --
837 -------------
844 begin
845 -- Normally we want to use the underlying type, but if it's not set
846 -- then continue with T.
863 then
864 -- The expression for a dynamic component may be rewritten
865 -- as a dereference, so retrieve original node.
869 -- Return True if the expression is a call to a function
870 -- (including an attribute function such as Image) with
871 -- a result that requires a transient scope.
877 then
890 else
895 -- Start of processing for Check_Initialization_Call
897 begin
898 -- Establish a transient scope if the type needs it
905 ------------------------------
906 -- Check_Parameterless_Call --
907 ------------------------------
913 -- If the prefix is of an access_to_subprogram type, the node must be
914 -- rewritten as a call. Ditto if the prefix is overloaded and all its
915 -- interpretations are access to subprograms.
917 ---------------------------
918 -- Prefix_Is_Access_Subp --
919 ---------------------------
925 begin
927 return
930 else
935 then
946 -- Start of processing for Check_Parameterless_Call
948 begin
949 -- Defend against junk stuff if errors already detected
956 then
963 -- If the context expects a value, and the name is a procedure, this is
964 -- most likely a missing 'Access. Don't try to resolve the parameterless
965 -- call, error will be caught when the outer call is analyzed.
970 and then
972 N_Function_Call,
973 N_Procedure_Call_Statement)
974 then
978 -- Rewrite as call if overloadable entity that is (or could be, in the
979 -- overloaded case) a function call. If we know for sure that the entity
980 -- is an enumeration literal, we do not rewrite it.
987 -- Rewrite as call if it is an explicit deference of an expression of
988 -- a subprogram access type, and the subprogram type is not that of a
989 -- procedure or entry.
991 or else
994 -- Rewrite as call if it is a selected component which is a function,
995 -- this is the case of a call to a protected function (which may be
996 -- overloaded with other protected operations).
998 or else
1001 or else
1003 or else
1007 -- If one of the above three conditions is met, rewrite as call.
1008 -- Apply the rewriting only once.
1010 then
1013 then
1016 -- If overloaded, overload set belongs to new copy
1020 -- Change node to parameterless function call (note that the
1021 -- Parameter_Associations associations field is left set to Empty,
1022 -- its normal default value since there are no parameters)
1035 -----------------------------
1036 -- Is_Definite_Access_Type --
1037 -----------------------------
1041 begin
1047 ----------------------
1048 -- Is_Predefined_Op --
1049 ----------------------
1052 begin
1060 -----------------------------
1061 -- Make_Call_Into_Operator --
1062 -----------------------------
1064 procedure Make_Call_Into_Operator
1068 is
1083 -- If the operand is not universal, and the operator is given by a
1084 -- expanded name, verify that the operand has an interpretation with
1085 -- a type defined in the given scope of the operator.
1088 -- Find a type of the given class in the package Pack that contains
1089 -- the operator.
1091 ---------------------------
1092 -- Operand_Type_In_Scope --
1093 ---------------------------
1100 begin
1104 else
1118 ---------------
1119 -- Type_In_P --
1120 ---------------
1126 -- Verify that node is not part of the type declaration for the
1127 -- candidate type, which would otherwise be invisible.
1129 -------------
1130 -- In_Decl --
1131 -------------
1137 begin
1146 else
1149 loop
1152 else
1161 -- Start of processing for Type_In_P
1163 begin
1164 -- If the context type is declared in the prefix package, this
1165 -- is the desired base type.
1169 then
1172 else
1176 and then not In_Decl
1177 then
1188 -- Start of processing for Make_Call_Into_Operator
1190 begin
1193 -- Binary operator
1203 -- Unary operator
1205 else
1211 -- If the operator is denoted by an expanded name, and the prefix is
1212 -- not Standard, but the operator is a predefined one whose scope is
1213 -- Standard, then this is an implicit_operator, inserted as an
1214 -- interpretation by the procedure of the same name. This procedure
1215 -- overestimates the presence of implicit operators, because it does
1216 -- not examine the type of the operands. Verify now that the operand
1217 -- type appears in the given scope. If right operand is universal,
1218 -- check the other operand. In the case of concatenation, either
1219 -- argument can be the component type, so check the type of the result.
1220 -- If both arguments are literals, look for a type of the right kind
1221 -- defined in the given scope. This elaborate nonsense is brought to
1222 -- you courtesy of b33302a. The type itself must be frozen, so we must
1223 -- find the type of the proper class in the given scope.
1225 -- A final wrinkle is the multiplication operator for fixed point
1226 -- types, which is defined in Standard only, and not in the scope of
1227 -- the fixed_point type itself.
1232 -- If the entity being called is defined in the given package,
1233 -- it is a renaming of a predefined operator, and known to be
1234 -- legal.
1238 then
1241 -- Visibility does not need to be checked in an instance: if the
1242 -- operator was not visible in the generic it has been diagnosed
1243 -- already, else there is an implicit copy of it in the instance.
1252 then
1257 -- Ada 2005, AI-420: Predefined equality on Universal_Access
1258 -- is available.
1263 then
1266 else
1275 and then Is_Binary
1277 then
1283 -- Verify that the scope contains a type that corresponds to
1284 -- the given literal. Optimize the case where Pack is Standard.
1306 else
1315 else
1324 then
1327 -- If the type is defined elsewhere, and the operator is not
1328 -- defined in the given scope (by a renaming declaration, e.g.)
1329 -- then this is an error as well. If an extension of System is
1330 -- present, and the type may be defined there, Pack must be
1331 -- System itself.
1338 then
1341 else
1347 then
1354 Error_Msg_NE
1365 else
1369 -- If this is a call to a function that renames a predefined equality,
1370 -- the renaming declaration provides a type that must be used to
1371 -- resolve the operands. This must be done now because resolution of
1372 -- the equality node will not resolve any remaining ambiguity, and it
1373 -- assumes that the first operand is not overloaded.
1378 then
1386 -- Do rewrite setting Comes_From_Source on the result if the original
1387 -- call came from source. Although it is not strictly the case that the
1388 -- operator as such comes from the source, logically it corresponds
1389 -- exactly to the function call in the source, so it should be marked
1390 -- this way (e.g. to make sure that validity checks work fine).
1392 declare
1394 begin
1399 -- If this is an arithmetic operator and the result type is private,
1400 -- the operands and the result must be wrapped in conversion to
1401 -- expose the underlying numeric type and expand the proper checks,
1402 -- e.g. on division.
1406 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
1407 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
1416 else
1420 -- For predefined operators on literals, the operation freezes
1421 -- their type.
1429 -------------------
1430 -- Operator_Kind --
1431 -------------------
1433 function Operator_Kind
1436 is
1439 begin
1475 else
1479 -- Unary operators
1481 else
1490 else
1498 ----------------------------
1499 -- Preanalyze_And_Resolve --
1500 ----------------------------
1505 begin
1509 -- We suppress all checks for this analysis, since the checks will
1510 -- be applied properly, and in the right location, when the default
1511 -- expression is reanalyzed and reexpanded later on.
1515 Expander_Mode_Restore;
1519 -- Version without context type
1524 begin
1531 Expander_Mode_Restore;
1535 ----------------------------------
1536 -- Replace_Actual_Discriminants --
1537 ----------------------------------
1545 -------------------
1546 -- Process_Discr --
1547 -------------------
1552 begin
1558 then
1574 -- Start of processing for Replace_Actual_Discriminants
1576 begin
1590 else
1595 -------------
1596 -- Resolve --
1597 -------------
1613 -- Determine whether a node comes from a predefined library unit or
1614 -- Standard.
1617 -- Try and fix up a literal so that it matches its expected type. New
1618 -- literals are manufactured if necessary to avoid cascaded errors.
1621 -- Called when attempt at resolving current expression fails
1623 ------------------------------------
1624 -- Comes_From_Predefined_Lib_Unit --
1625 -------------------------------------
1628 begin
1629 return
1635 --------------------
1636 -- Patch_Up_Value --
1637 --------------------
1640 begin
1643 then
1652 then
1661 then
1666 Char_Literal_Value =>
1673 then
1684 -----------------------
1685 -- Resolution_Failed --
1686 -----------------------
1689 begin
1695 -- The caller will return without calling the expander, so we need
1696 -- to set the analyzed flag. Note that it is fine to set Analyzed
1697 -- to True even if we are in the middle of a shallow analysis,
1698 -- (see the spec of sem for more details) since this is an error
1699 -- situation anyway, and there is no point in repeating the
1700 -- analysis later (indeed it won't work to repeat it later, since
1701 -- we haven't got a clear resolution of which entity is being
1702 -- referenced.)
1708 -- Start of processing for Resolve
1710 begin
1715 -- Access attribute on remote subprogram cannot be used for
1716 -- a non-remote access-to-subprogram type.
1727 then
1728 Error_Msg_N
1734 -- If the context is a Remote_Access_To_Subprogram, access attributes
1735 -- must be resolved with the corresponding fat pointer. There is no need
1736 -- to check for the attribute name since the return type of an
1737 -- attribute is never a remote type.
1743 then
1744 declare
1752 begin
1753 -- Check that Typ is a remote access-to-subprogram type
1756 -- Prefix (N) must statically denote a remote subprogram
1757 -- declared in a package specification.
1774 or else
1776 then
1778 Error_Msg_N
1780 N);
1784 -- If we are generating code for a distributed program.
1785 -- perform semantic checks against the corresponding
1786 -- remote entities.
1791 and then Expander_Active
1793 then
1794 Check_Subtype_Conformant
1796 Old_Id => Designated_Type
1817 then
1822 -- Return if already analyzed
1828 -- Return if type = Any_Type (previous error encountered)
1837 -- If not overloaded, then we know the type, and all that needs doing
1838 -- is to check that this type is compatible with the context.
1844 -- In the overloaded case, we must select the interpretation that
1845 -- is compatible with the context (i.e. the type passed to Resolve)
1847 else
1848 -- Loop through possible interpretations
1853 -- We are only interested in interpretations that are compatible
1854 -- with the expected type, any other interpretations are ignored.
1859 Write_Eol;
1862 else
1863 -- Skip the current interpretation if it is disabled by an
1864 -- abstract operator. This action is performed only when the
1865 -- type against which we are resolving is the same as the
1866 -- type of the interpretation.
1873 then
1877 -- First matching interpretation
1885 -- Matching interpretation that is not the first, maybe an
1886 -- error, but there are some cases where preference rules are
1887 -- used to choose between the two possibilities. These and
1888 -- some more obscure cases are handled in Disambiguate.
1890 else
1891 -- If the current statement is part of a predefined library
1892 -- unit, then all interpretations which come from user level
1893 -- packages should not be considered.
1895 if From_Lib
1897 then
1904 -- Disambiguation has succeeded. Skip the remaining
1905 -- interpretations.
1915 else
1916 -- Before we issue an ambiguity complaint, check for
1917 -- the case of a subprogram call where at least one
1918 -- of the arguments is Any_Type, and if so, suppress
1919 -- the message, since it is a cascaded error.
1922 N_Procedure_Call_Statement)
1923 then
1924 declare
1928 begin
1940 Write_Eol;
1953 then
1958 then
1962 -- Not that special case, so issue message using the
1963 -- flag Ambiguous to control printing of the header
1964 -- message only at the start of an ambiguous set.
1969 then
1970 Error_Msg_N
1973 else
1974 Error_Msg_NE
1982 Error_Msg_N
1984 else
1991 -- By default, the error message refers to the candidate
1992 -- interpretation. But if it is a predefined operator, it
1993 -- is implicitly declared at the declaration of the type
1994 -- of the operand. Recover the sloc of that declaration
1995 -- for the error message.
2001 Standard_Standard
2002 then
2007 then
2015 Standard_Standard
2016 then
2021 then
2025 -- If this is an indirect call, use the subprogram_type
2026 -- in the message, to have a meaningful location.
2027 -- Indicate as well if this is an inherited operation,
2028 -- created by a type declaration.
2033 then
2035 Error_Msg_Sloc :=
2037 else
2044 then
2045 -- Special-case the message for universal_fixed
2046 -- operators, which are not declared with the type
2047 -- of the operand, but appear forever in Standard.
2051 then
2052 Error_Msg_N
2056 else
2057 Error_Msg_N
2061 elsif
2063 then
2064 Error_Msg_N
2066 else
2073 -- We have a matching interpretation, Expr_Type is the type
2074 -- from this interpretation, and Seen is the entity.
2076 -- For an operator, just set the entity name. The type will be
2077 -- set by the specific operator resolution routine.
2086 -- For an explicit dereference, attribute reference, range,
2087 -- short-circuit form (which is not an operator node), or call
2088 -- with a name that is an explicit dereference, there is
2089 -- nothing to be done at this point.
2092 N_Attribute_Reference,
2093 N_And_Then,
2094 N_Indexed_Component,
2095 N_Or_Else,
2096 N_Range,
2097 N_Selected_Component,
2098 N_Slice)
2100 then
2103 -- For procedure or function calls, set the type of the name,
2104 -- and also the entity pointer for the prefix
2109 then
2116 then
2121 -- For all other cases, just set the type of the Name
2123 else
2131 -- Move to next interpretation
2139 -- At this stage Found indicates whether or not an acceptable
2140 -- interpretation exists. If not, then we have an error, except
2141 -- that if the context is Any_Type as a result of some other error,
2142 -- then we suppress the error report.
2147 -- If type we are looking for is Void, then this is the procedure
2148 -- call case, and the error is simply that what we gave is not a
2149 -- procedure name (we think of procedure calls as expressions with
2150 -- types internally, but the user doesn't think of them this way!)
2154 -- Special case message if function used as a procedure
2159 then
2160 Error_Msg_NE
2164 -- Otherwise give general message (not clear what cases this
2165 -- covers, but no harm in providing for them!)
2167 else
2173 -- Otherwise we do have a subexpression with the wrong type
2175 -- Check for the case of an allocator which uses an access type
2176 -- instead of the designated type. This is a common error and we
2177 -- specialize the message, posting an error on the operand of the
2178 -- allocator, complaining that we expected the designated type of
2179 -- the allocator.
2185 then
2189 -- Check for view mismatch on Null in instances, for which the
2190 -- view-swapping mechanism has no identifier.
2196 then
2201 -- Check for an aggregate. Sometimes we can get bogus aggregates
2202 -- from misuse of parentheses, and we are about to complain about
2203 -- the aggregate without even looking inside it.
2205 -- Instead, if we have an aggregate of type Any_Composite, then
2206 -- analyze and resolve the component fields, and then only issue
2207 -- another message if we get no errors doing this (otherwise
2208 -- assume that the errors in the aggregate caused the problem).
2212 then
2213 -- Disable expansion in any case. If there is a type mismatch
2214 -- it may be fatal to try to expand the aggregate. The flag
2215 -- would otherwise be set to false when the error is posted.
2219 declare
2221 -- Check one aggregate, and set Found to True if we have a
2222 -- definite error in any of its elements
2225 -- Check one element of aggregate and set Found to True if
2226 -- we definitely have an error in the element.
2228 ----------------
2229 -- Check_Aggr --
2230 ----------------
2235 begin
2248 -- If this is a default-initialized component, then
2249 -- there is nothing to check. The box will be
2250 -- replaced by the appropriate call during late
2251 -- expansion.
2262 ----------------
2263 -- Check_Elmt --
2264 ----------------
2267 begin
2268 -- If we have a nested aggregate, go inside it (to
2269 -- attempt a naked analyze-resolve of the aggregate
2270 -- can cause undesirable cascaded errors). Do not
2271 -- resolve expression if it needs a type from context,
2272 -- as for integer * fixed expression.
2277 else
2282 then
2292 begin
2297 -- If an error message was issued already, Found got reset
2298 -- to True, so if it is still False, issue the standard
2299 -- Wrong_Type message.
2304 then
2305 declare
2307 begin
2313 -- Protected operation: retrieve operation name
2316 else
2326 declare
2330 begin
2337 Error_Msg_NE
2343 else
2346 else
2352 Resolution_Failed;
2355 -- Test if we have more than one interpretation for the context
2358 Resolution_Failed;
2361 -- Here we have an acceptable interpretation for the context
2363 else
2364 -- Propagate type information and normalize tree for various
2365 -- predefined operations. If the context only imposes a class of
2366 -- types, rather than a specific type, propagate the actual type
2367 -- downward.
2374 then
2377 -- Any_Fixed is legal in a real context only if a specific
2378 -- fixed point type is imposed. If Norman Cohen can be
2379 -- confused by this, it deserves a separate message.
2383 then
2390 -- A user-defined operator is transformed into a function call at
2391 -- this point, so that further processing knows that operators are
2392 -- really operators (i.e. are predefined operators). User-defined
2393 -- operators that are intrinsic are just renamings of the predefined
2394 -- ones, and need not be turned into calls either, but if they rename
2395 -- a different operator, we must transform the node accordingly.
2396 -- Instantiations of Unchecked_Conversion are intrinsic but are
2397 -- treated as functions, even if given an operator designator.
2402 then
2408 and then
2410 N_Subprogram_Renaming_Declaration
2411 then
2414 -- If the node is rewritten, it will be fully resolved in
2415 -- Rewrite_Renamed_Operator.
2425 when N_Aggregate => Resolve_Aggregate (N, Ctx_Type);
2427 when N_Allocator => Resolve_Allocator (N, Ctx_Type);
2429 when N_And_Then | N_Or_Else
2430 => Resolve_Short_Circuit (N, Ctx_Type);
2432 when N_Attribute_Reference
2433 => Resolve_Attribute (N, Ctx_Type);
2435 when N_Character_Literal
2436 => Resolve_Character_Literal (N, Ctx_Type);
2438 when N_Conditional_Expression
2439 => Resolve_Conditional_Expression (N, Ctx_Type);
2441 when N_Expanded_Name
2442 => Resolve_Entity_Name (N, Ctx_Type);
2444 when N_Extension_Aggregate
2445 => Resolve_Extension_Aggregate (N, Ctx_Type);
2447 when N_Explicit_Dereference
2448 => Resolve_Explicit_Dereference (N, Ctx_Type);
2450 when N_Function_Call
2451 => Resolve_Call (N, Ctx_Type);
2453 when N_Identifier
2454 => Resolve_Entity_Name (N, Ctx_Type);
2456 when N_Indexed_Component
2457 => Resolve_Indexed_Component (N, Ctx_Type);
2459 when N_Integer_Literal
2460 => Resolve_Integer_Literal (N, Ctx_Type);
2462 when N_Membership_Test
2463 => Resolve_Membership_Op (N, Ctx_Type);
2465 when N_Null => Resolve_Null (N, Ctx_Type);
2467 when N_Op_And | N_Op_Or | N_Op_Xor
2468 => Resolve_Logical_Op (N, Ctx_Type);
2470 when N_Op_Eq | N_Op_Ne
2471 => Resolve_Equality_Op (N, Ctx_Type);
2473 when N_Op_Lt | N_Op_Le | N_Op_Gt | N_Op_Ge
2474 => Resolve_Comparison_Op (N, Ctx_Type);
2476 when N_Op_Not => Resolve_Op_Not (N, Ctx_Type);
2478 when N_Op_Add | N_Op_Subtract | N_Op_Multiply |
2479 N_Op_Divide | N_Op_Mod | N_Op_Rem
2481 => Resolve_Arithmetic_Op (N, Ctx_Type);
2483 when N_Op_Concat => Resolve_Op_Concat (N, Ctx_Type);
2485 when N_Op_Expon => Resolve_Op_Expon (N, Ctx_Type);
2487 when N_Op_Plus | N_Op_Minus | N_Op_Abs
2488 => Resolve_Unary_Op (N, Ctx_Type);
2490 when N_Op_Shift => Resolve_Shift (N, Ctx_Type);
2492 when N_Procedure_Call_Statement
2493 => Resolve_Call (N, Ctx_Type);
2495 when N_Operator_Symbol
2496 => Resolve_Operator_Symbol (N, Ctx_Type);
2498 when N_Qualified_Expression
2499 => Resolve_Qualified_Expression (N, Ctx_Type);
2501 when N_Raise_xxx_Error
2502 => Set_Etype (N, Ctx_Type);
2504 when N_Range => Resolve_Range (N, Ctx_Type);
2506 when N_Real_Literal
2507 => Resolve_Real_Literal (N, Ctx_Type);
2509 when N_Reference => Resolve_Reference (N, Ctx_Type);
2511 when N_Selected_Component
2512 => Resolve_Selected_Component (N, Ctx_Type);
2514 when N_Slice => Resolve_Slice (N, Ctx_Type);
2516 when N_String_Literal
2517 => Resolve_String_Literal (N, Ctx_Type);
2519 when N_Subprogram_Info
2520 => Resolve_Subprogram_Info (N, Ctx_Type);
2522 when N_Type_Conversion
2523 => Resolve_Type_Conversion (N, Ctx_Type);
2525 when N_Unchecked_Expression =>
2526 Resolve_Unchecked_Expression (N, Ctx_Type);
2528 when N_Unchecked_Type_Conversion =>
2529 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
2531 end case;
2533 -- If the subexpression was replaced by a non-subexpression, then
2534 -- all we do is to expand it. The only legitimate case we know of
2535 -- is converting procedure call statement to entry call statements,
2536 -- but there may be others, so we are making this test general.
2538 if Nkind (N) not in N_Subexpr then
2539 Debug_A_Exit ("resolving ", N, " (done)");
2540 Expand (N);
2541 return;
2542 end if;
2544 -- The expression is definitely NOT overloaded at this point, so
2545 -- we reset the Is_Overloaded flag to avoid any confusion when
2546 -- reanalyzing the node.
2548 Set_Is_Overloaded (N, False);
2550 -- Freeze expression type, entity if it is a name, and designated
2551 -- type if it is an allocator (RM 13.14(10,11,13)).
2553 -- Now that the resolution of the type of the node is complete,
2554 -- and we did not detect an error, we can expand this node. We
2555 -- skip the expand call if we are in a default expression, see
2556 -- section "Handling of Default Expressions" in Sem spec.
2558 Debug_A_Exit ("resolving ", N, " (done)");
2560 -- We unconditionally freeze the expression, even if we are in
2561 -- default expression mode (the Freeze_Expression routine tests
2562 -- this flag and only freezes static types if it is set).
2564 Freeze_Expression (N);
2566 -- Now we can do the expansion
2568 Expand (N);
2569 end if;
2570 end Resolve;
2572 -------------
2573 -- Resolve --
2574 -------------
2576 -- Version with check(s) suppressed
2578 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
2579 begin
2580 if Suppress = All_Checks then
2581 declare
2582 Svg : constant Suppress_Array := Scope_Suppress;
2583 begin
2584 Scope_Suppress := (others => True);
2585 Resolve (N, Typ);
2586 Scope_Suppress := Svg;
2587 end;
2589 else
2590 declare
2591 Svg : constant Boolean := Scope_Suppress (Suppress);
2592 begin
2593 Scope_Suppress (Suppress) := True;
2594 Resolve (N, Typ);
2595 Scope_Suppress (Suppress) := Svg;
2596 end;
2597 end if;
2598 end Resolve;
2600 -------------
2601 -- Resolve --
2602 -------------
2604 -- Version with implicit type
2606 procedure Resolve (N : Node_Id) is
2607 begin
2608 Resolve (N, Etype (N));
2609 end Resolve;
2611 ---------------------
2612 -- Resolve_Actuals --
2613 ---------------------
2615 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
2616 Loc : constant Source_Ptr := Sloc (N);
2617 A : Node_Id;
2618 F : Entity_Id;
2619 A_Typ : Entity_Id;
2620 F_Typ : Entity_Id;
2621 Prev : Node_Id := Empty;
2622 Orig_A : Node_Id;
2624 procedure Check_Argument_Order;
2625 -- Performs a check for the case where the actuals are all simple
2626 -- identifiers that correspond to the formal names, but in the wrong
2627 -- order, which is considered suspicious and cause for a warning.
2629 procedure Check_Prefixed_Call;
2630 -- If the original node is an overloaded call in prefix notation,
2632 -- Try_Object_Operation has already verified that there is a valid
2633 -- interpretation, but the form of the actual can only be determined
2634 -- once the primitive operation is identified.
2637 -- If the actual is missing in a call, insert in the actuals list
2638 -- an instance of the default expression. The insertion is always
2639 -- a named association.
2642 -- Check whether T1 and T2, or their full views, are derived from a
2643 -- common type. Used to enforce the restrictions on array conversions
2644 -- of AI95-00246.
2646 --------------------------
2647 -- Check_Argument_Order --
2648 --------------------------
2651 begin
2652 -- Nothing to do if no parameters, or original node is neither a
2653 -- function call nor a procedure call statement (happens in the
2654 -- operator-transformed-to-function call case), or the call does
2655 -- not come from source, or this warning is off.
2657 if not Warn_On_Parameter_Order
2658 or else
2660 or else
2662 N_Function_Call)
2663 or else
2665 then
2669 declare
2672 begin
2673 -- Nothing to do if only one parameter
2679 -- Here if at least two arguments
2681 declare
2687 -- Set True if an out of order case is found
2689 begin
2690 -- Collect identifier names of actuals, fail if any actual is
2691 -- not a simple identifier, and record max length of name.
2697 else
2703 -- If we got this far, all actuals are identifiers and the list
2704 -- of their names is stored in the Actuals array.
2709 -- If we ran out of formals, that's odd, probably an error
2710 -- which will be detected elsewhere, but abandon the search.
2716 -- If name matches and is in order OK
2721 else
2722 -- If no match, see if it is elsewhere in list and if so
2723 -- flag potential wrong order if type is compatible.
2727 and then
2729 then
2735 -- No match
2743 -- If Formals left over, also probably an error, skip warning
2749 -- Here we give the warning if something was out of order
2752 Error_Msg_N
2759 -------------------------
2760 -- Check_Prefixed_Call --
2761 -------------------------
2770 begin
2771 -- Check whether the call is a prefixed call, with or without
2772 -- additional actuals.
2775 or else
2781 then
2784 then
2785 -- Introduce dereference on object in prefix
2787 New_A :=
2795 then
2796 -- Introduce an implicit 'Access in prefix
2799 Error_Msg_NE
2815 --------------------
2816 -- Insert_Default --
2817 --------------------
2823 begin
2824 -- Missing argument in call, nothing to insert
2829 else
2830 -- Note that we do a full New_Copy_Tree, so that any associated
2831 -- Itypes are properly copied. This may not be needed any more,
2832 -- but it does no harm as a safety measure! Defaults of a generic
2833 -- formal may be out of bounds of the corresponding actual (see
2834 -- cc1311b) and an additional check may be required.
2836 Actval :=
2837 New_Copy_Tree
2844 then
2850 then
2853 then
2854 -- If default is a real literal, do not introduce a
2855 -- conversion whose effect may depend on the run-time
2856 -- size of universal real.
2860 else
2871 -- Resolve aggregates with their base type, to avoid scope
2872 -- anomalies: the subtype was first built in the subprogram
2873 -- declaration, and the current call may be nested.
2877 then
2879 else
2883 else
2886 -- See note above concerning aggregates
2890 then
2893 -- Resolve entities with their own type, which may differ
2894 -- from the type of a reference in a generic context (the
2895 -- view swapping mechanism did not anticipate the re-analysis
2896 -- of default values in calls).
2901 else
2906 -- If default is a tag indeterminate function call, propagate
2907 -- tag to obtain proper dispatching.
2911 then
2917 -- If the default expression raises constraint error, then just
2918 -- silently replace it with an N_Raise_Constraint_Error node,
2919 -- since we already gave the warning on the subprogram spec.
2929 Assoc :=
2934 -- Case of insertion is first named actual
2938 then
2945 else
2949 else
2953 -- Case of insertion is not first named actual
2955 else
2956 Set_Next_Named_Actual
2968 -------------------
2969 -- Same_Ancestor --
2970 -------------------
2976 begin
2979 then
2985 then
2992 -- Start of processing for Resolve_Actuals
2994 begin
2995 Check_Argument_Order;
2998 Check_Prefixed_Call;
3007 -- If we have an error in any actual or formal, indicated by
3008 -- a type of Any_Type, then abandon resolution attempt, and
3009 -- set result type to Any_Type.
3013 then
3018 -- Case where actual is present
3020 -- If the actual is an entity, generate a reference to it now. We
3021 -- do this before the actual is resolved, because a formal of some
3022 -- protected subprogram, or a task discriminant, will be rewritten
3023 -- during expansion, and the reference to the source entity may
3024 -- be lost.
3029 then
3035 then
3045 or else
3047 then
3048 -- If style checking mode on, check match of formal name
3056 -- If the formal is Out or In_Out, do not resolve and expand the
3057 -- conversion, because it is subsequently expanded into explicit
3058 -- temporaries and assignments. However, the object of the
3059 -- conversion can be resolved. An exception is the case of tagged
3060 -- type conversion with a class-wide actual. In that case we want
3061 -- the tag check to occur and no temporary will be needed (no
3062 -- representation change can occur) and the parameter is passed by
3063 -- reference, so we go ahead and resolve the type conversion.
3064 -- Another exception is the case of reference to component or
3065 -- subcomponent of a bit-packed array, in which case we want to
3066 -- defer expansion to the point the in and out assignments are
3067 -- performed.
3072 then
3075 then
3078 then
3080 -- In a view conversion, the conversion must be legal in
3081 -- both directions, and thus both component types must be
3082 -- aliased, or neither (4.6 (8)).
3084 -- The additional rule 4.6 (24.9.2) seems unduly
3085 -- restrictive: the privacy requirement should not
3086 -- apply to generic types, and should be checked in
3087 -- an instance. ARG query is in order.
3089 Error_Msg_N
3093 elsif
3095 then
3098 then
3099 Error_Msg_N
3102 else
3103 declare
3105 Component_Type
3107 begin
3110 and then
3115 then
3116 Error_Msg_N
3130 then
3134 -- If the actual is a function call that returns a limited
3135 -- unconstrained object that needs finalization, create a
3136 -- transient scope for it, so that it can receive the proper
3137 -- finalization list.
3142 and then Expander_Active
3143 and then
3145 then
3148 else
3152 and then
3155 then
3156 Error_Msg_N
3169 -- (Ada 2005: AI-251): If the actual is an allocator whose
3170 -- directly designated type is a class-wide interface, we build
3171 -- an anonymous access type to use it as the type of the
3172 -- allocator. Later, when the subprogram call is expanded, if
3173 -- the interface has a secondary dispatch table the expander
3174 -- will add a type conversion to force the correct displacement
3175 -- of the pointer.
3178 declare
3184 begin
3187 then
3195 -- Ada 2005, AI-162:If the actual is an allocator, the
3196 -- innermost enclosing statement is the master of the
3197 -- created object. This needs to be done with expansion
3198 -- enabled only, otherwise the transient scope will not
3199 -- be removed in the expansion of the wrapped construct.
3202 and then Expander_Active
3203 then
3209 -- (Ada 2005): The call may be to a primitive operation of
3210 -- a tagged synchronized type, declared outside of the type.
3211 -- In this case the controlling actual must be converted to
3212 -- its corresponding record type, which is the formal type.
3213 -- The actual may be a subtype, either because of a constraint
3214 -- or because it is a generic actual, so use base type to
3215 -- locate concurrent type.
3220 then
3222 Unchecked_Convert_To
3232 -- For mode IN, if actual is an entity, and the type of the formal
3233 -- has warnings suppressed, then we reset Never_Set_In_Source for
3234 -- the calling entity. The reason for this is to catch cases like
3235 -- GNAT.Spitbol.Patterns.Vstring_Var where the called subprogram
3236 -- uses trickery to modify an IN parameter.
3243 then
3247 -- Perform error checks for IN and IN OUT parameters
3251 -- Check unset reference. For scalar parameters, it is clearly
3252 -- wrong to pass an uninitialized value as either an IN or
3253 -- IN-OUT parameter. For composites, it is also clearly an
3254 -- error to pass a completely uninitialized value as an IN
3255 -- parameter, but the case of IN OUT is trickier. We prefer
3256 -- not to give a warning here. For example, suppose there is
3257 -- a routine that sets some component of a record to False.
3258 -- It is perfectly reasonable to make this IN-OUT and allow
3259 -- either initialized or uninitialized records to be passed
3260 -- in this case.
3262 -- For partially initialized composite values, we also avoid
3263 -- warnings, since it is quite likely that we are passing a
3264 -- partially initialized value and only the initialized fields
3265 -- will in fact be read in the subprogram.
3270 then
3274 -- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
3275 -- actual to a nested call, since this is case of reading an
3276 -- out parameter, which is not allowed.
3281 then
3286 -- Case of OUT or IN OUT parameter
3290 -- For an Out parameter, check for useless assignment. Note
3291 -- that we can't set Last_Assignment this early, because we may
3292 -- kill current values in Resolve_Call, and that call would
3293 -- clobber the Last_Assignment field.
3295 -- Note: call Warn_On_Useless_Assignment before doing the check
3296 -- below for Is_OK_Variable_For_Out_Formal so that the setting
3297 -- of Referenced_As_LHS/Referenced_As_Out_Formal properly
3298 -- reflects the last assignment, not this one!
3305 then
3310 -- Validate the form of the actual. Note that the call to
3311 -- Is_OK_Variable_For_Out_Formal generates the required
3312 -- reference in this case.
3318 -- What's the following about???
3322 else
3323 Kill_All_Checks;
3332 -- Apply appropriate range checks for in, out, and in-out
3333 -- parameters. Out and in-out parameters also need a separate
3334 -- check, if there is a type conversion, to make sure the return
3335 -- value meets the constraints of the variable before the
3336 -- conversion.
3338 -- Gigi looks at the check flag and uses the appropriate types.
3339 -- For now since one flag is used there is an optimization which
3340 -- might not be done in the In Out case since Gigi does not do
3341 -- any analysis. More thought required about this ???
3345 then
3357 then
3363 then
3369 then
3372 else
3376 -- Ada 2005 (AI-231)
3382 then
3383 Apply_Compile_Time_Constraint_Error
3393 then
3396 Apply_Scalar_Range_Check
3398 else
3399 Apply_Range_Check
3403 else
3409 then
3412 else
3418 -- An actual associated with an access parameter is implicitly
3419 -- converted to the anonymous access type of the formal and must
3420 -- satisfy the legality checks for access conversions.
3424 Error_Msg_N
3429 -- Check bad case of atomic/volatile argument (RM C.6(12))
3433 then
3436 then
3437 Error_Msg_N
3439 N);
3443 then
3444 Error_Msg_N
3446 N);
3450 -- Check that subprograms don't have improper controlling
3451 -- arguments (RM 3.9.2 (9))
3453 -- A primitive operation may have an access parameter of an
3454 -- incomplete tagged type, but a dispatching call is illegal
3455 -- if the type is still incomplete.
3461 declare
3463 begin
3467 then
3468 Error_Msg_NE
3482 then
3487 then
3489 Error_Msg_NE
3499 and then
3503 then
3504 Error_Msg_N
3509 then
3511 Error_Msg_NE
3518 -- If it is a named association, treat the selector_name as
3519 -- a proper identifier, and mark the corresponding entity.
3536 -- Case where actual is not present
3538 else
3539 Insert_Default;
3546 -----------------------
3547 -- Resolve_Allocator --
3548 -----------------------
3559 procedure Check_Allocator_Discrim_Accessibility
3562 -- Check that accessibility level associated with an access discriminant
3563 -- initialized in an allocator by the expression Disc_Exp is not deeper
3564 -- than the level of the allocator type Alloc_Typ. An error message is
3565 -- issued if this condition is violated. Specialized checks are done for
3566 -- the cases of a constraint expression which is an access attribute or
3567 -- an access discriminant.
3570 -- If the allocator is an actual in a call, it is allowed to be class-
3571 -- wide when the context is not because it is a controlling actual.
3574 -- Propagate all nested coextensions which are located one nesting
3575 -- level down the tree to the node Root. Example:
3576 --
3577 -- Top_Record
3578 -- Level_1_Coextension
3579 -- Level_2_Coextension
3580 --
3581 -- The algorithm is paired with delay actions done by the Expander. In
3582 -- the above example, assume all coextensions are controlled types.
3583 -- The cycle of analysis, resolution and expansion will yield:
3584 --
3585 -- 1) Analyze Top_Record
3586 -- 2) Analyze Level_1_Coextension
3587 -- 3) Analyze Level_2_Coextension
3588 -- 4) Resolve Level_2_Coextension. The allocator is marked as a
3589 -- coextension.
3590 -- 5) Expand Level_2_Coextension. A temporary variable Temp_1 is
3591 -- generated to capture the allocated object. Temp_1 is attached
3592 -- to the coextension chain of Level_2_Coextension.
3593 -- 6) Resolve Level_1_Coextension. The allocator is marked as a
3594 -- coextension. A forward tree traversal is performed which finds
3595 -- Level_2_Coextension's list and copies its contents into its
3596 -- own list.
3597 -- 7) Expand Level_1_Coextension. A temporary variable Temp_2 is
3598 -- generated to capture the allocated object. Temp_2 is attached
3599 -- to the coextension chain of Level_1_Coextension. Currently, the
3600 -- contents of the list are [Temp_2, Temp_1].
3601 -- 8) Resolve Top_Record. A forward tree traversal is performed which
3602 -- finds Level_1_Coextension's list and copies its contents into
3603 -- its own list.
3604 -- 9) Expand Top_Record. Generate finalization calls for Temp_1 and
3605 -- Temp_2 and attach them to Top_Record's finalization list.
3607 -------------------------------------------
3608 -- Check_Allocator_Discrim_Accessibility --
3609 -------------------------------------------
3611 procedure Check_Allocator_Discrim_Accessibility
3614 is
3615 begin
3618 then
3619 Error_Msg_N
3622 -- When the expression is an Access attribute the level of the prefix
3623 -- object must not be deeper than that of the allocator's type.
3627 = Attribute_Access
3630 then
3631 Error_Msg_N
3633 Disc_Exp);
3635 -- When the expression is an access discriminant the check is against
3636 -- the level of the prefix object.
3642 then
3643 Error_Msg_N
3645 Disc_Exp);
3647 -- All other cases are legal
3649 else
3654 ----------------------------
3655 -- In_Dispatching_Context --
3656 ----------------------------
3660 begin
3666 ----------------------------
3667 -- Propagate_Coextensions --
3668 ----------------------------
3673 -- Copy the contents of list From into list To, preserving the
3674 -- order of elements.
3677 -- Recognize an allocator or a rewritten allocator node and add it
3678 -- along with its nested coextensions to the list of Root.
3680 ---------------
3681 -- Copy_List --
3682 ---------------
3686 begin
3694 -----------------------
3695 -- Process_Allocator --
3696 -----------------------
3701 begin
3702 -- This is a possible rewritten subtype indication allocator. Any
3703 -- nested coextensions will appear as discriminant constraints.
3708 then
3709 declare
3713 begin
3715 Discr_Elmt :=
3725 then
3730 Copy_List
3738 -- There is no need to continue the traversal of this
3739 -- subtree since all the information has already been
3740 -- propagated.
3746 -- Case of either a stand alone allocator or a rewritten allocator
3747 -- with an aggregate.
3749 else
3756 -- Propagate the list of nested coextensions to the Root
3757 -- allocator. This is done through list copy since a single
3758 -- allocator may have multiple coextensions. Do not touch
3759 -- coextensions roots.
3763 then
3768 Copy_List
3773 -- There is no need to continue the traversal of this
3774 -- subtree since all the information has already been
3775 -- propagated.
3781 -- Keep on traversing, looking for the next allocator
3789 -- Start of processing for Propagate_Coextensions
3791 begin
3795 -- Start of processing for Resolve_Allocator
3797 begin
3798 -- Replace general access with specific type
3808 -- For qualified expression, resolve the expression using the
3809 -- given subtype (nothing to do for type mark, subtype indication)
3814 and then not In_Dispatching_Context
3815 then
3816 Error_Msg_N
3823 -- A qualified expression requires an exact match of the type,
3824 -- class-wide matching is not allowed.
3829 then
3833 -- A special accessibility check is needed for allocators that
3834 -- constrain access discriminants. The level of the type of the
3835 -- expression used to constrain an access discriminant cannot be
3836 -- deeper than the type of the allocator (in contrast to access
3837 -- parameters, where the level of the actual can be arbitrary).
3839 -- We can't use Valid_Conversion to perform this check because
3840 -- in general the type of the allocator is unrelated to the type
3841 -- of the access discriminant.
3845 then
3852 then
3855 -- Get the first component expression of the aggregate
3865 else
3869 else
3888 else
3893 else
3902 -- For a subtype mark or subtype indication, freeze the subtype
3904 else
3908 Error_Msg_N
3912 -- A special accessibility check is needed for allocators that
3913 -- constrain access discriminants. The level of the type of the
3914 -- expression used to constrain an access discriminant cannot be
3915 -- deeper than the type of the allocator (in contrast to access
3916 -- parameters, where the level of the actual can be arbitrary).
3917 -- We can't use Valid_Conversion to perform this check because
3918 -- in general the type of the allocator is unrelated to the type
3919 -- of the access discriminant.
3924 then
3934 else
3948 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
3949 -- check that the level of the type of the created object is not deeper
3950 -- than the level of the allocator's access type, since extensions can
3951 -- now occur at deeper levels than their ancestor types. This is a
3952 -- static accessibility level check; a run-time check is also needed in
3953 -- the case of an initialized allocator with a class-wide argument (see
3954 -- Expand_Allocator_Expression).
3958 then
3959 declare
3962 begin
3967 else
3976 E);
3982 -- Do not apply Ada 2005 accessibility checks on a class-wide
3983 -- allocator if the type given in the allocator is a formal
3984 -- type. A run-time check will be performed in the instance.
3994 -- Check for allocation from an empty storage pool
3997 declare
3999 begin
4007 -- If the context is an unchecked conversion, as may happen within
4008 -- an inlined subprogram, the allocator is being resolved with its
4009 -- own anonymous type. In that case, if the target type has a specific
4010 -- storage pool, it must be inherited explicitly by the allocator type.
4014 then
4015 Set_Associated_Storage_Pool
4019 -- An erroneous allocator may be rewritten as a raise Program_Error
4020 -- statement.
4024 -- An anonymous access discriminant is the definition of a
4025 -- coextension.
4029 N_Discriminant_Specification
4030 then
4031 -- Avoid marking an allocator as a dynamic coextension if it is
4032 -- within a static construct.
4038 -- Cleanup for potential static coextensions
4040 else
4045 -- There is no need to propagate any nested coextensions if they
4046 -- are marked as static since they will be rewritten on the spot.
4054 ---------------------------
4055 -- Resolve_Arithmetic_Op --
4056 ---------------------------
4058 -- Used for resolving all arithmetic operators except exponentiation
4069 -- We do the resolution using the base type, because intermediate values
4070 -- in expressions always are of the base type, not a subtype of it.
4073 -- Returns True if N is in a context that expects "any real type"
4076 -- Return True iff given type is Integer or universal real/integer
4079 -- Choose type of integer literal in fixed-point operation to conform
4080 -- to available fixed-point type. T is the type of the other operand,
4081 -- which is needed to determine the expected type of N.
4084 -- Set operand type to T if universal
4086 -------------------------------
4087 -- Expected_Type_Is_Any_Real --
4088 -------------------------------
4091 begin
4092 -- N is the expression after "delta" in a fixed_point_definition;
4093 -- see RM-3.5.9(6):
4096 N_Decimal_Fixed_Point_Definition,
4098 -- N is one of the bounds in a real_range_specification;
4099 -- see RM-3.5.7(5):
4101 N_Real_Range_Specification,
4103 -- N is the expression of a delta_constraint;
4104 -- see RM-J.3(3):
4106 N_Delta_Constraint);
4109 -----------------------------
4110 -- Is_Integer_Or_Universal --
4111 -----------------------------
4118 begin
4124 else
4130 then
4141 ----------------------------
4142 -- Set_Mixed_Mode_Operand --
4143 ----------------------------
4149 begin
4152 -- A universal integer literal is resolved as standard integer
4153 -- except in the case of a fixed-point result, where we leave it
4154 -- as universal (to be handled by Exp_Fixd later on)
4158 else
4166 then
4167 -- A universal real can appear in a fixed-type context. We resolve
4168 -- the literal with that context, even though this might raise an
4169 -- exception prematurely (the other operand may be zero).
4176 then
4177 -- Integer arg in mixed-mode operation. Resolve with universal
4178 -- type, in case preference rule must be applied.
4184 then
4185 -- Not a mixed-mode operation, resolve with context
4191 -- N may itself be a mixed-mode operation, so use context type
4198 then
4199 -- Must be (fixed * fixed) operation, operand must have one
4200 -- compatible interpretation.
4208 then
4209 -- C * F(X) in a fixed context, where C is a real literal or a
4210 -- fixed-point expression. F must have either a fixed type
4211 -- interpretation or an integer interpretation, but not both.
4219 else
4227 else
4235 -- Reanalyze the literal with the fixed type of the context. If
4236 -- context is Universal_Fixed, we are within a conversion, leave
4237 -- the literal as a universal real because there is no usable
4238 -- fixed type, and the target of the conversion plays no role in
4239 -- the resolution.
4241 declare
4245 begin
4248 else
4254 then
4256 else
4264 else
4269 ----------------------
4270 -- Set_Operand_Type --
4271 ----------------------
4274 begin
4277 then
4282 -- Start of processing for Resolve_Arithmetic_Op
4284 begin
4289 then
4293 -- Special-case for mixed-mode universal expressions or fixed point
4294 -- type operation: each argument is resolved separately. The same
4295 -- treatment is required if one of the operands of a fixed point
4296 -- operation is universal real, since in this case we don't do a
4297 -- conversion to a specific fixed-point type (instead the expander
4298 -- takes care of the case).
4303 then
4314 or else
4317 then
4322 -- If context is a fixed type and one operand is integer, the
4323 -- other is resolved with the type of the context.
4328 then
4335 then
4339 else
4344 -- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
4345 -- multiplying operators from being used when the expected type is
4346 -- also universal_fixed. Note that B_Typ will be Universal_Fixed in
4347 -- some cases where the expected type is actually Any_Real;
4348 -- Expected_Type_Is_Any_Real takes care of that case.
4352 then
4356 N_Unchecked_Type_Conversion)
4357 then
4364 else
4367 and then not
4369 N_Unchecked_Type_Conversion)
4370 then
4371 Error_Msg_N
4376 -- The expected type is "any real type" in contexts like
4377 -- type T is delta <universal_fixed-expression> ...
4378 -- in which case we need to set the type to Universal_Real
4379 -- so that static expression evaluation will work properly.
4383 else
4393 then
4398 -- If no previous errors, this is only possible if one operand
4399 -- is overloaded and the context is universal. Resolve as such.
4404 else
4406 and then
4408 then
4412 -- If the context is Universal_Fixed and the operands are also
4413 -- universal fixed, this is an error, unless there is only one
4414 -- applicable fixed_point type (usually duration).
4422 else
4427 else
4432 -- If one of the arguments was resolved to a non-universal type.
4433 -- label the result of the operation itself with the same type.
4434 -- Do the same for the universal argument, if any.
4445 -- Set overflow and division checking bit. Much cleverer code needed
4446 -- here eventually and perhaps the Resolve routines should be separated
4447 -- for the various arithmetic operations, since they will need
4448 -- different processing. ???
4455 -- Give warning if explicit division by zero
4459 then
4465 or else
4468 then
4469 -- Specialize the warning message according to the operation
4473 Apply_Compile_Time_Constraint_Error
4478 Apply_Compile_Time_Constraint_Error
4483 Apply_Compile_Time_Constraint_Error
4487 -- Division by zero can only happen with division, rem,
4488 -- and mod operations.
4494 -- Otherwise just set the flag to check at run time
4496 else
4501 -- If Restriction No_Implicit_Conditionals is active, then it is
4502 -- violated if either operand can be negative for mod, or for rem
4503 -- if both operands can be negative.
4507 then
4508 declare
4515 -- Set if corresponding operand might be negative
4517 begin
4525 or else
4527 then
4538 ------------------
4539 -- Resolve_Call --
4540 ------------------
4552 begin
4553 -- The context imposes a unique interpretation with type Typ on a
4554 -- procedure or function call. Find the entity of the subprogram that
4555 -- yields the expected type, and propagate the corresponding formal
4556 -- constraints on the actuals. The caller has established that an
4557 -- interpretation exists, and emitted an error if not unique.
4559 -- First deal with the case of a call to an access-to-subprogram,
4560 -- dereference made explicit in Analyze_Call.
4566 else
4567 -- Find the interpretation whose type (a subprogram type) has a
4568 -- return type that is compatible with the context. Analysis of
4569 -- the node has established that one exists.
4588 -- If the prefix is not an entity, then resolve it
4594 -- For an indirect call, we always invalidate checks, since we do not
4595 -- know whether the subprogram is local or global. Yes we could do
4596 -- better here, e.g. by knowing that there are no local subprograms,
4597 -- but it does not seem worth the effort. Similarly, we kill all
4598 -- knowledge of current constant values.
4600 Kill_Current_Values;
4602 -- If this is a procedure call which is really an entry call, do
4603 -- the conversion of the procedure call to an entry call. Protected
4604 -- operations use the same circuitry because the name in the call
4605 -- can be an arbitrary expression with special resolution rules.
4610 then
4614 -- Kill checks and constant values, as above for indirect case
4615 -- Who knows what happens when another task is activated?
4617 Kill_Current_Values;
4620 -- Normal subprogram call with name established in Resolve
4626 -- Otherwise we must have the case of an overloaded call
4628 else
4644 -- Check that a call to Current_Task does not occur in an entry body
4647 declare
4650 begin
4652 loop
4655 -- Exclude calls that occur within the default of a formal
4656 -- parameter of the entry, since those are evaluated outside
4657 -- of the body.
4664 then
4666 Error_Msg_NE
4669 Error_Msg_NE
4681 -- Check that a procedure call does not occur in the context of the
4682 -- entry call statement of a conditional or timed entry call. Note that
4683 -- the case of a call to a subprogram renaming of an entry will also be
4684 -- rejected. The test for N not being an N_Entry_Call_Statement is
4685 -- defensive, covering the possibility that the processing of entry
4686 -- calls might reach this point due to later modifications of the code
4687 -- above.
4692 then
4696 -- Ada 2005 (AI-345): If a procedure_call_statement is used
4697 -- for a procedure_or_entry_call, the procedure_name or pro-
4698 -- cedure_prefix of the procedure_call_statement shall denote
4699 -- an entry renamed by a procedure, or (a view of) a primitive
4700 -- subprogram of a limited interface whose first parameter is
4701 -- a controlling parameter.
4706 then
4707 Error_Msg_N
4712 -- Check that this is not a call to a protected procedure or
4713 -- entry from within a protected function.
4719 then
4725 -- Freeze the subprogram name if not in a spec-expression. Note that we
4726 -- freeze procedure calls as well as function calls. Procedure calls are
4727 -- not frozen according to the rules (RM 13.14(14)) because it is
4728 -- impossible to have a procedure call to a non-frozen procedure in pure
4729 -- Ada, but in the code that we generate in the expander, this rule
4730 -- needs extending because we can generate procedure calls that need
4731 -- freezing.
4737 -- For a predefined operator, the type of the result is the type imposed
4738 -- by context, except for a predefined operation on universal fixed.
4739 -- Otherwise The type of the call is the type returned by the subprogram
4740 -- being called.
4747 -- If the subprogram returns an array type, and the context requires the
4748 -- component type of that array type, the node is really an indexing of
4749 -- the parameterless call. Resolve as such. A pathological case occurs
4750 -- when the type of the component is an access to the array type. In
4751 -- this case the call is truly ambiguous.
4754 and then
4759 and then
4762 then
4763 declare
4768 begin
4771 then
4772 Error_Msg_N
4774 else
4781 -- Indexed call to a parameterless function
4783 Index_Node :=
4785 Prefix =>
4789 else
4790 -- An Ada 2005 prefixed call to a primitive operation
4791 -- whose first parameter is the prefix. This prefix was
4792 -- prepended to the parameter list, which is actually a
4793 -- list of indices. Remove the prefix in order to build
4794 -- the proper indexed component.
4796 Index_Node :=
4798 Prefix =>
4801 Parameter_Associations =>
4802 New_List
4807 -- Since we are correcting a node classification error made
4808 -- by the parser, we call Replace rather than Rewrite.
4821 else
4825 -- In the case where the call is to an overloaded subprogram, Analyze
4826 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
4827 -- such a case Normalize_Actuals needs to be called once more to order
4828 -- the actuals correctly. Otherwise the call will have the ordering
4829 -- given by the last overloaded subprogram whether this is the correct
4830 -- one being called or not.
4837 -- In any case, call is fully resolved now. Reset Overload flag, to
4838 -- prevent subsequent overload resolution if node is analyzed again
4843 -- If we are calling the current subprogram from immediately within its
4844 -- body, then that is the case where we can sometimes detect cases of
4845 -- infinite recursion statically. Do not try this in case restriction
4846 -- No_Recursion is in effect anyway, and do it only for source calls.
4851 -- Issue warning for possible infinite recursion in the absence
4852 -- of the No_Recursion restriction.
4857 then
4858 -- Here we detected and flagged an infinite recursion, so we do
4859 -- not need to test the case below for further warnings. Also if
4860 -- we now have a raise SE node, we are all done.
4866 -- If call is to immediately containing subprogram, then check for
4867 -- the case of a possible run-time detectable infinite recursion.
4869 else
4873 -- Although in general case, recursion is not statically
4874 -- checkable, the case of calling an immediately containing
4875 -- subprogram is easy to catch.
4879 -- If the recursive call is to a parameterless subprogram,
4880 -- then even if we can't statically detect infinite
4881 -- recursion, this is pretty suspicious, and we output a
4882 -- warning. Furthermore, we will try later to detect some
4883 -- cases here at run time by expanding checking code (see
4884 -- Detect_Infinite_Recursion in package Exp_Ch6).
4886 -- If the recursive call is within a handler, do not emit a
4887 -- warning, because this is a common idiom: loop until input
4888 -- is correct, catch illegal input in handler and restart.
4894 then
4895 -- For the case of a procedure call. We give the message
4896 -- only if the call is the first statement in a sequence
4897 -- of statements, or if all previous statements are
4898 -- simple assignments. This is simply a heuristic to
4899 -- decrease false positives, without losing too many good
4900 -- warnings. The idea is that these previous statements
4901 -- may affect global variables the procedure depends on.
4905 then
4906 declare
4908 begin
4920 -- Do not give warning if we are in a conditional context
4922 declare
4924 begin
4930 then
4935 -- Here warning is to be issued
4938 Error_Msg_N
4940 Error_Msg_N
4952 -- If subprogram name is a predefined operator, it was given in
4953 -- functional notation. Replace call node with operator node, so
4954 -- that actuals can be resolved appropriately.
4962 then
4968 -- Create a transient scope if the resulting type requires it
4970 -- There are 4 notable exceptions: in init procs, the transient scope
4971 -- overhead is not needed and even incorrect due to the actual expansion
4972 -- of adjust calls; the second case is enumeration literal pseudo calls;
4973 -- the third case is intrinsic subprograms (Unchecked_Conversion and
4974 -- source information functions) that do not use the secondary stack
4975 -- even though the return type is unconstrained; the fourth case is a
4976 -- call to a build-in-place function, since such functions may allocate
4977 -- their result directly in a target object, and cases where the result
4978 -- does get allocated in the secondary stack are checked for within the
4979 -- specialized Exp_Ch6 procedures for expanding build-in-place calls.
4981 -- If this is an initialization call for a type whose initialization
4982 -- uses the secondary stack, we also need to create a transient scope
4983 -- for it, precisely because we will not do it within the init proc
4984 -- itself.
4986 -- If the subprogram is marked Inline_Always, then even if it returns
4987 -- an unconstrained type the call does not require use of the secondary
4988 -- stack. However, inlining will only take place if the body to inline
4989 -- is already present. It may not be available if e.g. the subprogram is
4990 -- declared in a child instance.
4996 then
4999 elsif Expander_Active
5004 and then not Within_Init_Proc
5006 then
5009 -- If the call appears within the bounds of a loop, it will
5010 -- be rewritten and reanalyzed, nothing left to do here.
5017 and then not Within_Init_Proc
5018 then
5022 -- A protected function cannot be called within the definition of the
5023 -- enclosing protected type.
5028 then
5029 Error_Msg_NE
5033 -- Propagate interpretation to actuals, and add default expressions
5034 -- where needed.
5039 -- Overloaded literals are rewritten as function calls, for
5040 -- purpose of resolution. After resolution, we can replace
5041 -- the call with the literal itself.
5047 -- Avoid validation, since it is a static function call
5053 -- If the subprogram is not global, then kill all saved values and
5054 -- checks. This is a bit conservative, since in many cases we could do
5055 -- better, but it is not worth the effort. Similarly, we kill constant
5056 -- values. However we do not need to do this for internal entities
5057 -- (unless they are inherited user-defined subprograms), since they
5058 -- are not in the business of molesting local values.
5060 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
5061 -- kill all checks and values for calls to global subprograms. This
5062 -- takes care of the case where an access to a local subprogram is
5063 -- taken, and could be passed directly or indirectly and then called
5064 -- from almost any context.
5066 -- Note: we do not do this step till after resolving the actuals. That
5067 -- way we still take advantage of the current value information while
5068 -- scanning the actuals.
5070 -- We suppress killing values if we are processing the nodes associated
5071 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
5072 -- type kills all the values as part of analyzing the code that
5073 -- initializes the dispatch tables.
5081 then
5082 Kill_Current_Values;
5085 -- If we are warning about unread OUT parameters, this is the place to
5086 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
5087 -- after the above call to Kill_Current_Values (since that call clears
5088 -- the Last_Assignment field of all local variables).
5093 then
5094 declare
5098 begin
5109 then
5119 -- If the subprogram is a primitive operation, check whether or not
5120 -- it is a correct dispatching call.
5124 then
5129 and then not In_Instance
5130 then
5134 -- If this is a dispatching call, generate the appropriate reference,
5135 -- for better source navigation in GPS.
5139 then
5141 else
5149 -- Check for violation of restriction No_Specific_Termination_Handlers
5152 or else
5154 then
5158 -- All done, evaluate call and deal with elaboration issues
5164 -------------------------------
5165 -- Resolve_Character_Literal --
5166 -------------------------------
5172 begin
5173 -- Verify that the character does belong to the type of the context
5178 -- Wide_Wide_Character literals must always be defined, since the set
5179 -- of wide wide character literals is complete, i.e. if a character
5180 -- literal is accepted by the parser, then it is OK for wide wide
5181 -- character (out of range character literals are rejected).
5186 -- Always accept character literal for type Any_Character, which
5187 -- occurs in error situations and in comparisons of literals, both
5188 -- of which should accept all literals.
5193 -- For Standard.Character or a type derived from it, check that
5194 -- the literal is in range
5201 -- For Standard.Wide_Character or a type derived from it, check
5202 -- that the literal is in range
5209 -- For Standard.Wide_Wide_Character or a type derived from it, we
5210 -- know the literal is in range, since the parser checked!
5215 -- If the entity is already set, this has already been resolved in
5216 -- a generic context, or comes from expansion. Nothing else to do.
5221 -- Otherwise we have a user defined character type, and we can use
5222 -- the standard visibility mechanisms to locate the referenced entity
5224 else
5237 -- If we fall through, then the literal does not match any of the
5238 -- entries of the enumeration type. This isn't just a constraint
5239 -- error situation, it is an illegality (see RM 4.2).
5241 Error_Msg_NE
5245 ---------------------------
5246 -- Resolve_Comparison_Op --
5247 ---------------------------
5249 -- Context requires a boolean type, and plays no role in resolution.
5250 -- Processing identical to that for equality operators. The result
5251 -- type is the base type, which matters when pathological subtypes of
5252 -- booleans with limited ranges are used.
5259 begin
5260 -- If this is an intrinsic operation which is not predefined, use
5261 -- the types of its declared arguments to resolve the possibly
5262 -- overloaded operands. Otherwise the operands are unambiguous and
5263 -- specify the expected type.
5268 else
5283 then
5286 else
5293 else
5304 ------------------------------------
5305 -- Resolve_Conditional_Expression --
5306 ------------------------------------
5313 begin
5322 -----------------------------------------
5323 -- Resolve_Discrete_Subtype_Indication --
5324 -----------------------------------------
5326 procedure Resolve_Discrete_Subtype_Indication
5329 is
5333 begin
5341 else
5351 Error_Msg_NE
5354 -- Rewrite the constraint as a range of Typ
5355 -- to allow compilation to proceed further.
5367 else
5371 -- Additionally, we must check that the bounds are compatible
5372 -- with the given subtype, which might be different from the
5373 -- type of the context.
5377 -- ??? If the above check statically detects a Constraint_Error
5378 -- it replaces the offending bound(s) of the range R with a
5379 -- Constraint_Error node. When the itype which uses these bounds
5380 -- is frozen the resulting call to Duplicate_Subexpr generates
5381 -- a new temporary for the bounds.
5383 -- Unfortunately there are other itypes that are also made depend
5384 -- on these bounds, so when Duplicate_Subexpr is called they get
5385 -- a forward reference to the newly created temporaries and Gigi
5386 -- aborts on such forward references. This is probably sign of a
5387 -- more fundamental problem somewhere else in either the order of
5388 -- itype freezing or the way certain itypes are constructed.
5390 -- To get around this problem we call Remove_Side_Effects right
5391 -- away if either bounds of R are a Constraint_Error.
5393 declare
5397 begin
5413 -------------------------
5414 -- Resolve_Entity_Name --
5415 -------------------------
5417 -- Used to resolve identifiers and expanded names
5422 begin
5423 -- If garbage from errors, set to Any_Type and return
5430 -- Replace named numbers by corresponding literals. Note that this is
5431 -- the one case where Resolve_Entity_Name must reset the Etype, since
5432 -- it is currently marked as universal.
5442 -- Allow use of subtype only if it is a concurrent type where we are
5443 -- currently inside the body. This will eventually be expanded
5444 -- into a call to Self (for tasks) or _object (for protected
5445 -- objects). Any other use of a subtype is invalid.
5450 then
5452 else
5453 Error_Msg_N
5457 -- Check discriminant use if entity is discriminant in current scope,
5458 -- i.e. discriminant of record or concurrent type currently being
5459 -- analyzed. Uses in corresponding body are unrestricted.
5464 then
5467 -- A parameterless generic function cannot appear in a context that
5468 -- requires resolution.
5479 then
5482 -- In all other cases, just do the possible static evaluation
5484 else
5485 -- A deferred constant that appears in an expression must have
5486 -- a completion, unless it has been removed by in-place expansion
5487 -- of an aggregate.
5493 and then not In_Spec_Expression
5495 then
5500 then
5502 else
5503 Error_Msg_N (
5512 -------------------
5513 -- Resolve_Entry --
5514 -------------------
5526 -- If the bounds of the entry family being called depend on task
5527 -- discriminants, build a new index subtype where a discriminant is
5528 -- replaced with the value of the discriminant of the target task.
5529 -- The target task is the prefix of the entry name in the call.
5531 -----------------------
5532 -- Actual_Index_Type --
5533 -----------------------
5543 -- If the bound is given by a discriminant, replace with a reference
5544 -- to the discriminant of the same name in the target task.
5545 -- If the entry name is the target of a requeue statement and the
5546 -- entry is in the current protected object, the bound to be used
5547 -- is the discriminal of the object (see apply_range_checks for
5548 -- details of the transformation).
5550 -----------------------------
5551 -- Actual_Discriminant_Ref --
5552 -----------------------------
5558 begin
5563 then
5569 then
5572 else
5573 Ref :=
5583 -- Start of processing for Actual_Index_Type
5585 begin
5589 then
5592 else
5606 -- Start of processing of Resolve_Entry
5608 begin
5609 -- Find name of entry being called, and resolve prefix of name
5610 -- with its own type. The prefix can be overloaded, and the name
5611 -- and signature of the entry must be taken into account.
5615 -- Case of dealing with entry family within the current tasks
5619 else
5624 -- Entry call to an entry (or entry family) in the current task.
5625 -- This is legal even though the task will deadlock. Rewrite as
5626 -- call to current task.
5628 -- This can also be a call to an entry in an enclosing task.
5629 -- If this is a single task, we have to retrieve its name,
5630 -- because the scope of the entry is the task type, not the
5631 -- object. If the enclosing task is a task type, the identity
5632 -- of the task is given by its own self variable.
5634 -- Finally this can be a requeue on an entry of the same task
5635 -- or protected object.
5643 then
5644 -- S is an enclosing task or protected object. The concurrent
5645 -- declaration has been converted into a type declaration, and
5646 -- the object itself has an object declaration that follows
5647 -- the type in the same declarative part.
5659 -- Call to current task. Will be transformed into call to Self
5666 New_N :=
5669 Selector_Name =>
5676 then
5677 -- Use the entry name (which must be unique at this point) to
5678 -- find the prefix that returns the corresponding task type or
5679 -- protected type.
5681 declare
5687 begin
5709 -- Up to this point the expression could have been the actual
5710 -- in a simple entry call, and be given by a named association.
5714 else
5720 ------------------------
5721 -- Resolve_Entry_Call --
5722 ------------------------
5734 begin
5735 -- We kill all checks here, because it does not seem worth the
5736 -- effort to do anything better, an entry call is a big operation.
5738 Kill_All_Checks;
5740 -- Processing of the name is similar for entry calls and protected
5741 -- operation calls. Once the entity is determined, we can complete
5742 -- the resolution of the actuals.
5744 -- The selector may be overloaded, in the case of a protected object
5745 -- with overloaded functions. The type of the context is used for
5746 -- resolution.
5751 then
5752 declare
5756 begin
5775 -- Simple entry call
5783 -- Call to member of entry family
5790 -- We cannot in general check the maximum depth of protected entry
5791 -- calls at compile time. But we can tell that any protected entry
5792 -- call at all violates a specified nesting depth of zero.
5798 -- Use context type to disambiguate a protected function that can be
5799 -- called without actuals and that returns an array type, and where
5800 -- the argument list may be an indexing of the returned value.
5805 and then
5813 then
5814 declare
5817 begin
5818 Index_Node :=
5820 Prefix =>
5825 -- Since we are correcting a node classification error made by
5826 -- the parser, we call Replace rather than Rewrite.
5836 -- The operation name may have been overloaded. Order the actuals
5837 -- according to the formals of the resolved entity, and set the
5838 -- return type to that of the operation.
5851 then
5855 -- Verify that a procedure call cannot masquerade as an entry
5856 -- call where an entry call is expected.
5861 then
5866 then
5871 then
5876 -- After resolution, entry calls and protected procedure calls
5877 -- are changed into entry calls, for expansion. The structure
5878 -- of the node does not change, so it can safely be done in place.
5879 -- Protected function calls must keep their structure because they
5880 -- are subexpressions.
5884 -- A protected operation that is not a function may modify the
5885 -- corresponding object, and cannot apply to a constant.
5886 -- If this is an internal call, the prefix is the type itself.
5892 then
5893 Error_Msg_N
5895 Entry_Name);
5909 -- Protected functions can return on the secondary stack, in which
5910 -- case we must trigger the transient scope mechanism.
5912 elsif Expander_Active
5914 then
5919 -------------------------
5920 -- Resolve_Equality_Op --
5921 -------------------------
5923 -- Both arguments must have the same type, and the boolean context
5924 -- does not participate in the resolution. The first pass verifies
5925 -- that the interpretation is not ambiguous, and the type of the left
5926 -- argument is correctly set, or is Any_Type in case of ambiguity.
5927 -- If both arguments are strings or aggregates, allocators, or Null,
5928 -- they are ambiguous even though they carry a single (universal) type.
5929 -- Diagnose this case here.
5937 -- In the case of allocators, make a last-ditch attempt to find a single
5938 -- access type with the right designated type. This is semantically
5939 -- dubious, and of no interest to any real code, but c48008a makes it
5940 -- all worthwhile.
5942 -----------------------------
5943 -- Find_Unique_Access_Type --
5944 -----------------------------
5951 begin
5956 else
5968 then
5981 -- Start of processing for Resolve_Equality_Op
5983 begin
5995 then
5998 else
6008 then
6021 -- If the unique type is a class-wide type then it will be expanded
6022 -- into a dispatching call to the predefined primitive. Therefore we
6023 -- check here for potential violation of such restriction.
6029 if Warn_On_Redundant_Constructs
6034 then
6042 -- If this is an inequality, it may be the implicit inequality
6043 -- created for a user-defined operation, in which case the corres-
6044 -- ponding equality operation is not intrinsic, and the operation
6045 -- cannot be constant-folded. Else fold.
6050 or else Is_Intrinsic_Subprogram
6052 then
6057 then
6061 -- Ada 2005: If one operand is an anonymous access type, convert
6062 -- the other operand to it, to ensure that the underlying types
6063 -- match in the back-end. Same for access_to_subprogram, and the
6064 -- conversion verifies that the types are subtype conformant.
6066 -- We apply the same conversion in the case one of the operands is
6067 -- a private subtype of the type of the other.
6069 -- Why the Expander_Active test here ???
6071 if Expander_Active
6072 and then
6076 then
6096 ----------------------------------
6097 -- Resolve_Explicit_Dereference --
6098 ----------------------------------
6107 begin
6112 -- Use the context type to select the prefix that has the correct
6113 -- designated type.
6124 else
6125 -- If no interpretation covers the designated type of the prefix,
6126 -- this is the pathological case where not all implementations of
6127 -- the prefix allow the interpretation of the node as a call. Now
6128 -- that the expected type is known, Remove other interpretations
6129 -- from prefix, rewrite it as a call, and resolve again, so that
6130 -- the proper call node is generated.
6141 New_N :=
6143 Name =>
6156 else
6164 -- If the designated type is a packed unconstrained array type, and the
6165 -- explicit dereference is not in the context of an attribute reference,
6166 -- then we must compute and set the actual subtype, since it is needed
6167 -- by Gigi. The reason we exclude the attribute case is that this is
6168 -- handled fine by Gigi, and in fact we use such attributes to build the
6169 -- actual subtype. We also exclude generated code (which builds actual
6170 -- subtypes directly if they are needed).
6177 then
6181 -- Note: there is no Eval processing required for an explicit deference,
6182 -- because the type is known to be an allocators, and allocator
6183 -- expressions can never be static.
6187 -------------------------------
6188 -- Resolve_Indexed_Component --
6189 -------------------------------
6197 begin
6200 -- Use the context type to select the prefix that yields the correct
6201 -- component type.
6203 declare
6210 begin
6217 and then Covers
6219 then
6228 else
6234 else
6245 else
6252 -- If prefix is access type, dereference to get real array type.
6253 -- Note: we do not apply an access check because the expander always
6254 -- introduces an explicit dereference, and the check will happen there.
6260 -- If name was overloaded, set component type correctly now
6261 -- If a misplaced call to an entry family (which has no index types)
6262 -- return. Error will be diagnosed from calling context.
6266 else
6273 -- The prefix may have resolved to a string literal, in which case its
6274 -- etype has a special representation. This is only possible currently
6275 -- if the prefix is a static concatenation, written in functional
6276 -- notation.
6281 else
6288 else
6297 -- Do not generate the warning on suspicious index if we are analyzing
6298 -- package Ada.Tags; otherwise we will report the warning with the
6299 -- Prims_Ptr field of the dispatch table.
6302 or else not
6304 Ada_Tags)
6305 then
6311 -----------------------------
6312 -- Resolve_Integer_Literal --
6313 -----------------------------
6316 begin
6321 --------------------------------
6322 -- Resolve_Intrinsic_Operator --
6323 --------------------------------
6331 begin
6341 -- If the operand type is private, rewrite with suitable conversions on
6342 -- the operands and the result, to expose the proper underlying numeric
6343 -- type.
6350 else
6366 then
6367 -- Add explicit conversion where needed, and save interpretations
6368 -- in case operands are overloaded.
6375 else
6381 else
6391 else
6396 --------------------------------------
6397 -- Resolve_Intrinsic_Unary_Operator --
6398 --------------------------------------
6400 procedure Resolve_Intrinsic_Unary_Operator
6403 is
6408 begin
6427 else
6432 ------------------------
6433 -- Resolve_Logical_Op --
6434 ------------------------
6440 begin
6441 -- Predefined operations on scalar types yield the base type. On the
6442 -- other hand, logical operations on arrays yield the type of the
6443 -- arguments (and the context).
6447 else
6451 -- The following test is required because the operands of the operation
6452 -- may be literals, in which case the resulting type appears to be
6453 -- compatible with a signed integer type, when in fact it is compatible
6454 -- only with modular types. If the context itself is universal, the
6455 -- operation is illegal.
6463 Error_Msg_N
6470 then
6484 -- Check for violation of restriction No_Direct_Boolean_Operators
6485 -- if the operator was not eliminated by the Eval_Logical_Op call.
6489 then
6494 ---------------------------
6495 -- Resolve_Membership_Op --
6496 ---------------------------
6498 -- The context can only be a boolean type, and does not determine
6499 -- the arguments. Arguments should be unambiguous, but the preference
6500 -- rule for universal types applies.
6509 begin
6515 and then
6519 then
6522 -- Ada 2005 (AI-251): Give support to the following case:
6524 -- type I is interface;
6525 -- type T is tagged ...
6527 -- function Test (O : I'Class) is
6528 -- begin
6529 -- return O in T'Class.
6530 -- end Test;
6532 -- In this case we have nothing else to do; the membership test will be
6533 -- done at run-time.
6540 then
6543 else
6552 then
6558 else
6566 ------------------
6567 -- Resolve_Null --
6568 ------------------
6571 begin
6572 -- Handle restriction against anonymous null access values This
6573 -- restriction can be turned off using -gnatdj.
6575 -- Ada 2005 (AI-231): Remove restriction
6578 and then not Debug_Flag_J
6581 then
6582 -- In the common case of a call which uses an explicitly null
6583 -- value for an access parameter, give specialized error message.
6586 N_Function_Call)
6587 then
6588 Error_Msg_N
6591 -- Standard message for all other cases (are there any?)
6593 else
6594 Error_Msg_N
6599 -- In a distributed context, null for a remote access to subprogram
6600 -- may need to be replaced with a special record aggregate. In this
6601 -- case, return after having done the transformation.
6606 then
6610 -- The null literal takes its type from the context
6615 -----------------------
6616 -- Resolve_Op_Concat --
6617 -----------------------
6621 -- We wish to avoid deep recursion, because concatenations are often
6622 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
6623 -- operands nonrecursively until we find something that is not a simple
6624 -- concatenation (A in this case). We resolve that, and then walk back
6625 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
6626 -- to do the rest of the work at each level. The Parent pointers allow
6627 -- us to avoid recursion, and thus avoid running out of memory. See also
6628 -- Sem_Ch4.Analyze_Concatenation, where a similar hack is used.
6633 begin
6634 -- The following code is equivalent to:
6636 -- Resolve_Op_Concat_First (NN, Typ);
6637 -- Resolve_Op_Concat_Arg (N, ...);
6638 -- Resolve_Op_Concat_Rest (N, Typ);
6640 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
6641 -- operand is a concatenation.
6643 -- Walk down left operands
6645 loop
6654 -- Now (given the above example) NN is A&B and Op1 is A
6656 -- First resolve Op1 ...
6660 -- ... then walk NN back up until we reach N (where we started), calling
6661 -- Resolve_Op_Concat_Rest along the way.
6663 loop
6670 ---------------------------
6671 -- Resolve_Op_Concat_Arg --
6672 ---------------------------
6674 procedure Resolve_Op_Concat_Arg
6679 is
6682 begin
6684 if Is_Comp
6688 then
6690 else
6697 then
6700 else
6705 else
6709 then
6710 declare
6715 begin
6720 -- Special-case the error message when the overloading is
6721 -- caused by a function that yields an array and can be
6722 -- called without parameters.
6727 Error_Msg_NE
6729 Error_Msg_NE
6733 else
6734 Error_Msg_N
6743 then
6761 else
6766 else
6773 -----------------------------
6774 -- Resolve_Op_Concat_First --
6775 -----------------------------
6782 begin
6783 -- The parser folds an enormous sequence of concatenations of string
6784 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
6785 -- in the right. If the expression resolves to a predefined "&"
6786 -- operator, all is well. Otherwise, the parser's folding is wrong, so
6787 -- we give an error. See P_Simple_Expression in Par.Ch4.
6792 then
6807 ----------------------------
6808 -- Resolve_Op_Concat_Rest --
6809 ----------------------------
6815 begin
6824 -- If this is not a static concatenation, but the result is a
6825 -- string type (and not an array of strings) ensure that static
6826 -- string operands have their subtypes properly constructed.
6830 then
6836 ----------------------
6837 -- Resolve_Op_Expon --
6838 ----------------------
6843 begin
6844 -- Catch attempts to do fixed-point exponentiation with universal
6845 -- operands, which is a case where the illegality is not caught during
6846 -- normal operator analysis.
6857 then
6864 then
6868 -- We do the resolution using the base type, because intermediate values
6869 -- in expressions always are of the base type, not a subtype of it.
6881 -- Set overflow checking bit. Much cleverer code needed here eventually
6882 -- and perhaps the Resolve routines should be separated for the various
6883 -- arithmetic operations, since they will need different processing. ???
6892 --------------------
6893 -- Resolve_Op_Not --
6894 --------------------
6900 -- This function determines if the parent node is a boolean operator
6901 -- or operation (comparison op, membership test, or short circuit form)
6902 -- and the not in question is the left operand of this operation.
6903 -- Note that if the not is in parens, then false is returned.
6905 -----------------------
6906 -- Parent_Is_Boolean --
6907 -----------------------
6910 begin
6914 else
6916 when N_Op_And |
6917 N_Op_Eq |
6918 N_Op_Ge |
6919 N_Op_Gt |
6920 N_Op_Le |
6921 N_Op_Lt |
6922 N_Op_Ne |
6923 N_Op_Or |
6924 N_Op_Xor |
6925 N_In |
6926 N_Not_In |
6927 N_And_Then |
6928 N_Or_Else =>
6938 -- Start of processing for Resolve_Op_Not
6940 begin
6941 -- Predefined operations on scalar types yield the base type. On the
6942 -- other hand, logical operations on arrays yield the type of the
6943 -- arguments (and the context).
6947 else
6951 -- Straightforward case of incorrect arguments
6958 -- Special case of probable missing parens
6962 Error_Msg_N
6965 else
6966 Error_Msg_N
6973 -- OK resolution of not
6975 else
6976 -- Warn if non-boolean types involved. This is a case like not a < b
6977 -- where a and b are modular, where we will get (not a) < b and most
6978 -- likely not (a < b) was intended.
6980 if Warn_On_Questionable_Missing_Parens
6982 and then Parent_Is_Boolean
6983 then
6987 -- Warn on double negation if checking redundant constructs
6989 if Warn_On_Redundant_Constructs
6994 then
6998 -- Complete resolution and evaluation of NOT
7008 -----------------------------
7009 -- Resolve_Operator_Symbol --
7010 -----------------------------
7012 -- Nothing to be done, all resolved already
7018 begin
7022 ----------------------------------
7023 -- Resolve_Qualified_Expression --
7024 ----------------------------------
7032 begin
7035 -- A qualified expression requires an exact match of the type,
7036 -- class-wide matching is not allowed. However, if the qualifying
7037 -- type is specific and the expression has a class-wide type, it
7038 -- may still be okay, since it can be the result of the expansion
7039 -- of a call to a dispatching function, so we also have to check
7040 -- class-wideness of the type of the expression's original node.
7043 or else
7047 then
7051 -- If the target type is unconstrained, then we reset the type of
7052 -- the result from the type of the expression. For other cases, the
7053 -- actual subtype of the expression is the target type.
7057 then
7064 -------------------
7065 -- Resolve_Range --
7066 -------------------
7072 begin
7080 -- We have to check the bounds for being within the base range as
7081 -- required for a non-static context. Normally this is automatic and
7082 -- done as part of evaluating expressions, but the N_Range node is an
7083 -- exception, since in GNAT we consider this node to be a subexpression,
7084 -- even though in Ada it is not. The circuit in Sem_Eval could check for
7085 -- this, but that would put the test on the main evaluation path for
7086 -- expressions.
7091 -- Check for an ambiguous range over character literals. This will
7092 -- happen with a membership test involving only literals.
7100 -- If bounds are static, constant-fold them, so size computations
7101 -- are identical between front-end and back-end. Do not perform this
7102 -- transformation while analyzing generic units, as type information
7103 -- would then be lost when reanalyzing the constant node in the
7104 -- instance.
7117 --------------------------
7118 -- Resolve_Real_Literal --
7119 --------------------------
7124 begin
7125 -- Special processing for fixed-point literals to make sure that the
7126 -- value is an exact multiple of small where this is required. We
7127 -- skip this for the universal real case, and also for generic types.
7133 then
7134 declare
7141 begin
7142 -- Case of literal is not an exact multiple of the Small
7146 -- For a source program literal for a decimal fixed-point
7147 -- type, this is statically illegal (RM 4.9(36)).
7152 then
7156 -- Generate a warning if literal from source
7159 and then Warn_On_Bad_Fixed_Value
7160 then
7161 Error_Msg_N
7163 N);
7166 -- Replace literal by a value that is the exact representation
7167 -- of a value of the type, i.e. a multiple of the small value,
7168 -- by truncation, since Machine_Rounds is false for all GNAT
7169 -- fixed-point types (RM 4.9(38)).
7179 -- In all cases, set the corresponding integer field
7185 -- Now replace the actual type by the expected type as usual
7191 -----------------------
7192 -- Resolve_Reference --
7193 -----------------------
7198 begin
7199 -- Replace general access with specific type
7207 -- If we are taking the reference of a volatile entity, then treat
7208 -- it as a potential modification of this entity. This is much too
7209 -- conservative, but is necessary because remove side effects can
7210 -- result in transformations of normal assignments into reference
7211 -- sequences that otherwise fail to notice the modification.
7218 --------------------------------
7219 -- Resolve_Selected_Component --
7220 --------------------------------
7235 -- Check whether this is the initialization of a component within an
7236 -- init proc (by assignment or call to another init proc). If true,
7237 -- there is no need for a discriminant check.
7239 --------------------
7240 -- Init_Component --
7241 --------------------
7244 begin
7245 return Inside_Init_Proc
7251 -- Start of processing for Resolve_Selected_Component
7253 begin
7256 -- Use the context type to select the prefix that has a selector
7257 -- of the correct name and type.
7265 else
7271 -- The visible components of a class-wide type are those of
7272 -- the root type.
7282 then
7289 else
7293 Error_Msg_N
7298 else
7301 -- There may be an implicit dereference. Retrieve
7302 -- designated record type.
7306 else
7312 -- Resolution chooses the new interpretation.
7313 -- Find the component with the right name.
7318 loop
7340 else
7341 -- Resolve prefix with its type
7346 -- Generate cross-reference. We needed to wait until full overloading
7347 -- resolution was complete to do this, since otherwise we can't tell if
7348 -- we are an Lvalue of not.
7352 else
7356 -- If prefix is an access type, the node will be transformed into an
7357 -- explicit dereference during expansion. The type of the node is the
7358 -- designated type of that of the prefix.
7363 else
7369 or else
7376 and then not Init_Component
7377 then
7385 -- If the prefix is a record conversion, this may be a renamed
7386 -- discriminant whose bounds differ from those of the original
7387 -- one, so we must ensure that a range check is performed.
7392 then
7396 -- Note: No Eval processing is required, because the prefix is of a
7397 -- record type, or protected type, and neither can possibly be static.
7401 -------------------
7402 -- Resolve_Shift --
7403 -------------------
7410 begin
7411 -- We do the resolution using the base type, because intermediate values
7412 -- in expressions always are of the base type, not a subtype of it.
7425 ---------------------------
7426 -- Resolve_Short_Circuit --
7427 ---------------------------
7434 begin
7438 -- Check for issuing warning for always False assert/check, this happens
7439 -- when assertions are turned off, in which case the pragma Assert/Check
7440 -- was transformed into:
7442 -- if False and then <condition> then ...
7444 -- and we detect this pattern
7446 if Warn_On_Assertion_Failure
7453 then
7454 declare
7457 begin
7460 then
7461 -- Don't want to warn if original condition is explicit False
7463 declare
7465 Original_Node
7466 (Expression
7468 begin
7471 then
7473 else
7474 -- Issue warning. Note that we don't want to make this
7475 -- an unconditional warning, because if the assert is
7476 -- within deleted code we do not want the warning. But
7477 -- we do not want the deletion of the IF/AND-THEN to
7478 -- take this message with it. We achieve this by making
7479 -- sure that the expanded code points to the Sloc of
7480 -- the expression, not the original pragma.
7486 -- Similar processing for Check pragma
7490 then
7491 -- Don't want to warn if original condition is explicit False
7493 declare
7495 Original_Node
7496 (Expression
7499 begin
7502 then
7504 else
7512 -- Continue with processing of short circuit
7521 -------------------
7522 -- Resolve_Slice --
7523 -------------------
7531 begin
7534 -- Use the context type to select the prefix that yields the
7535 -- correct array type.
7537 declare
7544 begin
7552 then
7560 else
7565 else
7576 else
7586 -- If the prefix is an access to an unconstrained array, we must use
7587 -- the actual subtype of the object to perform the index checks. The
7588 -- object denoted by the prefix is implicit in the node, so we build
7589 -- an explicit representation for it in order to compute the actual
7590 -- subtype.
7595 declare
7599 begin
7609 then
7612 -- If the name is a selected component that depends on discriminants,
7613 -- build an actual subtype for it. This can happen only when the name
7614 -- itself is overloaded; otherwise the actual subtype is created when
7615 -- the selected component is analyzed.
7618 and then Full_Analysis
7620 then
7621 declare
7624 begin
7630 -- If name was overloaded, set slice type correctly now
7634 -- If the range is specified by a subtype mark, no resolution is
7635 -- necessary. Else resolve the bounds, and apply needed checks.
7643 -- Do not apply the range check to nodes associated with the
7644 -- frontend expansion of the dispatch table. We first check
7645 -- if Ada.Tags is already loaded to void the addition of an
7646 -- undesired dependence on such run-time unit.
7648 and then
7650 or else not
7656 then
7671 ----------------------------
7672 -- Resolve_String_Literal --
7673 ----------------------------
7684 begin
7685 -- For a string appearing in a concatenation, defer creation of the
7686 -- string_literal_subtype until the end of the resolution of the
7687 -- concatenation, because the literal may be constant-folded away. This
7688 -- is a useful optimization for long concatenation expressions.
7690 -- If the string is an aggregate built for a single character (which
7691 -- happens in a non-static context) or a is null string to which special
7692 -- checks may apply, we build the subtype. Wide strings must also get a
7693 -- string subtype if they come from a one character aggregate. Strings
7694 -- generated by attributes might be static, but it is often hard to
7695 -- determine whether the enclosing context is static, so we generate
7696 -- subtypes for them as well, thus losing some rarer optimizations ???
7697 -- Same for strings that come from a static conversion.
7699 Need_Check :=
7708 -- If the resolving type is itself a string literal subtype, we
7709 -- can just reuse it, since there is no point in creating another.
7715 and then not Need_Check
7717 N_Attribute_Reference,
7718 N_Qualified_Expression,
7719 N_Type_Conversion)
7720 then
7723 -- Otherwise we must create a string literal subtype. Note that the
7724 -- whole idea of string literal subtypes is simply to avoid the need
7725 -- for building a full fledged array subtype for each literal.
7727 else
7733 or else Need_Check
7734 then
7741 then
7747 -- The validity of a null string has been checked in the
7748 -- call to Eval_String_Literal.
7753 -- Always accept string literal with component type Any_Character, which
7754 -- occurs in error situations and in comparisons of literals, both of
7755 -- which should accept all literals.
7760 -- If the type is bit-packed, then we always transform the string
7761 -- literal into a full fledged aggregate.
7766 -- Deal with cases of Wide_Wide_String, Wide_String, and String
7768 else
7769 -- For Standard.Wide_Wide_String, or any other type whose component
7770 -- type is Standard.Wide_Wide_Character, we know that all the
7771 -- characters in the string must be acceptable, since the parser
7772 -- accepted the characters as valid character literals.
7777 -- For the case of Standard.String, or any other type whose component
7778 -- type is Standard.Character, we must make sure that there are no
7779 -- wide characters in the string, i.e. that it is entirely composed
7780 -- of characters in range of type Character.
7782 -- If the string literal is the result of a static concatenation, the
7783 -- test has already been performed on the components, and need not be
7784 -- repeated.
7788 then
7792 -- If we are out of range, post error. This is one of the
7793 -- very few places that we place the flag in the middle of
7794 -- a token, right under the offending wide character.
7796 Error_Msg
7803 -- For the case of Standard.Wide_String, or any other type whose
7804 -- component type is Standard.Wide_Character, we must make sure that
7805 -- there are no wide characters in the string, i.e. that it is
7806 -- entirely composed of characters in range of type Wide_Character.
7808 -- If the string literal is the result of a static concatenation,
7809 -- the test has already been performed on the components, and need
7810 -- not be repeated.
7814 then
7818 -- If we are out of range, post error. This is one of the
7819 -- very few places that we place the flag in the middle of
7820 -- a token, right under the offending wide character.
7822 -- This is not quite right, because characters in general
7823 -- will take more than one character position ???
7825 Error_Msg
7832 -- If the root type is not a standard character, then we will convert
7833 -- the string into an aggregate and will let the aggregate code do
7834 -- the checking. Standard Wide_Wide_Character is also OK here.
7836 else
7840 -- See if the component type of the array corresponding to the string
7841 -- has compile time known bounds. If yes we can directly check
7842 -- whether the evaluation of the string will raise constraint error.
7843 -- Otherwise we need to transform the string literal into the
7844 -- corresponding character aggregate and let the aggregate
7845 -- code do the checking.
7849 -- Check for the case of full range, where we are definitely OK
7855 -- Here the range is not the complete base type range, so check
7857 declare
7865 begin
7868 then
7874 then
7875 Apply_Compile_Time_Constraint_Error
7887 -- If we got here we meed to transform the string literal into the
7888 -- equivalent qualified positional array aggregate. This is rather
7889 -- heavy artillery for this situation, but it is hard work to avoid.
7891 declare
7896 begin
7897 -- Build the character literals, we give them source locations that
7898 -- correspond to the string positions, which is a bit tricky given
7899 -- the possible presence of wide character escape sequences.
7913 -- Should we have a call to Skip_Wide here ???
7914 -- ??? else
7915 -- Skip_Wide (P);
7923 Expression =>
7930 -----------------------------
7931 -- Resolve_Subprogram_Info --
7932 -----------------------------
7935 begin
7939 -----------------------------
7940 -- Resolve_Type_Conversion --
7941 -----------------------------
7952 begin
7953 if not Conv_OK
7955 then
7961 -- Mixed-mode operation involving a literal. Context must be a fixed
7962 -- type which is applied to the literal subsequently.
7970 or else
7972 then
7973 -- Return if expression is ambiguous
7978 -- If nothing else, the available fixed type is Duration
7980 else
7984 -- Resolve the real operand with largest available precision
7988 else
7994 -- If the operand is a literal (it could be a non-static and
7995 -- illegal exponentiation) check whether the use of Duration
7996 -- is potentially inaccurate.
8001 then
8002 Error_Msg_N
8005 Rop);
8006 Error_Msg_N
8013 then
8016 else
8025 -- Note: we do the Eval_Type_Conversion call before applying the
8026 -- required checks for a subtype conversion. This is important,
8027 -- since both are prepared under certain circumstances to change
8028 -- the type conversion to a constraint error node, but in the case
8029 -- of Eval_Type_Conversion this may reflect an illegality in the
8030 -- static case, and we would miss the illegality (getting only a
8031 -- warning message), if we applied the type conversion checks first.
8035 -- Even when evaluation is not possible, we may be able to simplify
8036 -- the conversion or its expression. This needs to be done before
8037 -- applying checks, since otherwise the checks may use the original
8038 -- expression and defeat the simplifications. This is specifically
8039 -- the case for elimination of the floating-point Truncation
8040 -- attribute in float-to-int conversions.
8044 -- If after evaluation we still have a type conversion, then we
8045 -- may need to apply checks required for a subtype conversion.
8047 -- Skip these type conversion checks if universal fixed operands
8048 -- operands involved, since range checks are handled separately for
8049 -- these cases (in the appropriate Expand routines in unit Exp_Fixd).
8055 then
8059 -- Issue warning for conversion of simple object to its own type
8060 -- We have to test the original nodes, since they may have been
8061 -- rewritten by various optimizations.
8065 if Warn_On_Redundant_Constructs
8068 and then not In_Instance
8069 then
8073 -- If the node is part of a larger expression, the Target_Type
8074 -- may not be the original type of the node if the context is a
8075 -- condition. Recover original type to see if conversion is needed.
8079 then
8084 and then
8086 or else
8089 then
8091 Error_Msg_NE
8096 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
8097 -- No need to perform any interface conversion if the type of the
8098 -- expression coincides with the target type.
8101 and then Expander_Active
8103 then
8104 declare
8108 begin
8120 -- Conversion from interface type
8124 -- Ada 2005 (AI-217): Handle entities from limited views
8130 Error_Msg_N
8132 N);
8135 and then not
8138 then
8142 Error_Msg_N
8144 N);
8146 else
8150 -- Conversion to interface type
8154 -- Handle subtypes
8158 then
8162 if not Interface_Present_In_Ancestor
8165 then
8168 -- The static analysis is not enough to know if the
8169 -- interface is implemented or not. Hence we must pass
8170 -- the work to the expander to generate code to evaluate
8171 -- the conversion at run-time.
8175 else
8178 Error_Msg_N
8183 else
8191 ----------------------
8192 -- Resolve_Unary_Op --
8193 ----------------------
8202 begin
8203 -- Deal with intrinsic unary operators
8209 then
8214 -- Deal with universal cases
8217 or else
8219 then
8226 -- Generate warning for expressions like abs (x mod 2)
8228 if Warn_On_Redundant_Constructs
8230 then
8234 Error_Msg_N
8239 -- Deal with reference generation
8245 -- Set overflow checking bit. Much cleverer code needed here eventually
8246 -- and perhaps the Resolve routines should be separated for the various
8247 -- arithmetic operations, since they will need different processing ???
8255 -- Generate warning for expressions like -5 mod 3 for integers. No
8256 -- need to worry in the floating-point case, since parens do not affect
8257 -- the result so there is no point in giving in a warning.
8259 declare
8268 begin
8269 if Warn_On_Questionable_Missing_Parens
8273 then
8276 -- We are looking for cases where the right operand is not
8277 -- parenthesized, and is a binary operator, multiply, divide, or
8278 -- mod. These are the cases where the grouping can affect results.
8282 then
8283 -- For mod, we always give the warning, since the value is
8284 -- affected by the parenthesization (e.g. (-5) mod 315 /=
8285 -- (5 mod 315)). But for the other cases, the only concern is
8286 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
8287 -- overflows, but (-2) * 64 does not). So we try to give the
8288 -- message only when overflow is possible.
8292 then
8297 else
8303 else
8307 -- Note that the test below is deliberately excluding
8308 -- the largest negative number, since that is a potentially
8309 -- troublesome case (e.g. -2 * x, where the result is the
8310 -- largest negative integer has an overflow with 2 * x).
8317 -- For the multiplication case, the only case we have to worry
8318 -- about is when (-a)*b is exactly the largest negative number
8319 -- so that -(a*b) can cause overflow. This can only happen if
8320 -- a is a power of 2, and more generally if any operand is a
8321 -- constant that is not a power of 2, then the parentheses
8322 -- cannot affect whether overflow occurs. We only bother to
8323 -- test the left most operand
8325 -- Loop looking at left operands for one that has known value
8332 -- Operand value of 0 or 1 skips warning
8337 -- Otherwise check power of 2, if power of 2, warn, if
8338 -- anything else, skip warning.
8340 else
8344 else
8353 -- Keep looking at left operands
8358 -- For rem or "/" we can only have a problematic situation
8359 -- if the divisor has a value of minus one or one. Otherwise
8360 -- overflow is impossible (divisor > 1) or we have a case of
8361 -- division by zero in any case.
8366 then
8370 -- If we fall through warning should be issued
8372 Error_Msg_N
8379 ----------------------------------
8380 -- Resolve_Unchecked_Expression --
8381 ----------------------------------
8383 procedure Resolve_Unchecked_Expression
8386 is
8387 begin
8392 ---------------------------------------
8393 -- Resolve_Unchecked_Type_Conversion --
8394 ---------------------------------------
8396 procedure Resolve_Unchecked_Type_Conversion
8399 is
8405 begin
8406 -- Resolve operand using its own type
8413 ------------------------------
8414 -- Rewrite_Operator_As_Call --
8415 ------------------------------
8422 begin
8429 New_N :=
8440 ------------------------------
8441 -- Rewrite_Renamed_Operator --
8442 ------------------------------
8444 procedure Rewrite_Renamed_Operator
8448 is
8453 begin
8454 -- Rewrite the operator node using the real operator, not its
8455 -- renaming. Exclude user-defined intrinsic operations of the same
8456 -- name, which are treated separately and rewritten as calls.
8460 then
8467 -- Indicate that both the original entity and its renaming are
8468 -- referenced at this point.
8479 -- If the context type is private, add the appropriate conversions
8480 -- so that the operator is applied to the full view. This is done
8481 -- in the routines that resolve intrinsic operators,
8485 then
8487 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
8488 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
8501 then
8502 -- Operator renames a user-defined operator of the same name. Use
8503 -- the original operator in the node, which is the one that Gigi
8504 -- knows about.
8511 -----------------------
8512 -- Set_Slice_Subtype --
8513 -----------------------
8515 -- Build an implicit subtype declaration to represent the type delivered
8516 -- by the slice. This is an abbreviated version of an array subtype. We
8517 -- define an index subtype for the slice, using either the subtype name
8518 -- or the discrete range of the slice. To be consistent with index usage
8519 -- elsewhere, we create a list header to hold the single index. This list
8520 -- is not otherwise attached to the syntax tree.
8531 begin
8535 else
8536 -- We force the evaluation of a range. This is definitely needed in
8537 -- the renamed case, and seems safer to do unconditionally. Note in
8538 -- any case that since we will create and insert an Itype referring
8539 -- to this range, we must make sure any side effect removal actions
8540 -- are inserted before the Itype definition.
8569 -- The Etype of the existing Slice node is reset to this slice subtype.
8570 -- Its bounds are obtained from its first index.
8574 -- In the packed case, this must be immediately frozen
8576 -- Couldn't we always freeze here??? and if we did, then the above
8577 -- call to Check_Compile_Time_Size could be eliminated, which would
8578 -- be nice, because then that routine could be made private to Freeze.
8580 -- Why the test for In_Spec_Expression here ???
8588 --------------------------------
8589 -- Set_String_Literal_Subtype --
8590 --------------------------------
8598 begin
8612 -- The low bound is set from the low bound of the corresponding
8613 -- index type. Note that we do not store the high bound in the
8614 -- string literal subtype, but it can be deduced if necessary
8615 -- from the length and the low bound.
8619 else
8620 Set_String_Literal_Low_Bound
8624 -- Build bona fide subtype for the string, and wrap it in an
8625 -- unchecked conversion, because the backend expects the
8626 -- String_Literal_Subtype to have a static lower bound.
8628 declare
8634 Right_Opnd =>
8642 begin
8643 Index_Subtype :=
8650 -- In the context, the Index_Type may already have a constraint,
8651 -- so use common base type on string subtype. The base type may
8652 -- be used when generating attributes of the string, for example
8653 -- in the context of a slice assignment.
8678 ------------------------------
8679 -- Simplify_Type_Conversion --
8680 ------------------------------
8683 begin
8685 declare
8690 begin
8692 and then
8699 -- Special processing required if the conversion is the expression
8700 -- of a Truncation attribute reference. In this case we replace:
8702 -- ityp (ftyp'Truncation (x))
8704 -- by
8706 -- ityp (x)
8708 -- with the Float_Truncate flag set, which is more efficient
8710 then
8719 -----------------------------
8720 -- Unique_Fixed_Point_Type --
8721 -----------------------------
8730 -- If true ambiguity, give details
8732 -----------------------
8733 -- Fixed_Point_Error --
8734 -----------------------
8737 begin
8743 -- Start of processing for Unique_Fixed_Point_Type
8745 begin
8746 -- The operations on Duration are visible, so Duration is always a
8747 -- possible interpretation.
8751 -- Look for fixed-point types in enclosing scopes
8760 then
8762 Fixed_Point_Error;
8764 else
8775 -- Look for visible fixed type declarations in the context
8787 then
8789 Fixed_Point_Error;
8791 else
8805 else
8812 ----------------------
8813 -- Valid_Conversion --
8814 ----------------------
8816 function Valid_Conversion
8820 is
8824 function Conversion_Check
8827 -- Little routine to post Msg if Valid is False, returns Valid value
8829 function Valid_Tagged_Conversion
8832 -- Specifically test for validity of tagged conversions
8835 -- Check index and component conformance, and accessibility levels
8836 -- if the component types are anonymous access types (Ada 2005)
8838 ----------------------
8839 -- Conversion_Check --
8840 ----------------------
8842 function Conversion_Check
8845 is
8846 begin
8854 ----------------------------
8855 -- Valid_Array_Conversion --
8856 ----------------------------
8859 is
8874 begin
8875 -- Error if wrong number of dimensions
8877 if
8879 then
8880 Error_Msg_N
8884 -- Number of dimensions matches
8886 else
8887 -- Loop through indexes of the two arrays
8895 -- Error if index types are incompatible
8901 then
8902 Error_Msg_N
8904 Operand);
8912 -- If component types have same base type, all set
8917 -- Here if base types of components are not the same. The only
8918 -- time this is allowed is if we have anonymous access types.
8920 -- The conversion of arrays of anonymous access types can lead
8921 -- to dangling pointers. AI-392 formalizes the accessibility
8922 -- checks that must be applied to such conversions to prevent
8923 -- out-of-scope references.
8925 elsif
8927 or else
8930 and then
8932 then
8935 then
8940 Operand);
8947 -- Conversion not allowed because of accessibility levels
8949 else
8954 else
8958 -- All other cases where component base types do not match
8960 else
8961 Error_Msg_N
8963 Operand);
8967 -- Check that component subtypes statically match. For numeric
8968 -- types this means that both must be either constrained or
8969 -- unconstrained. For enumeration types the bounds must match.
8970 -- All of this is checked in Subtypes_Statically_Match.
8972 if not Subtypes_Statically_Match
8974 then
8975 Error_Msg_N
8984 -----------------------------
8985 -- Valid_Tagged_Conversion --
8986 -----------------------------
8988 function Valid_Tagged_Conversion
8991 is
8992 begin
8993 -- Upward conversions are allowed (RM 4.6(22))
8997 then
9000 -- Downward conversion are allowed if the operand is class-wide
9001 -- (RM 4.6(23)).
9005 then
9010 then
9011 return
9015 -- Ada 2005 (AI-251): The conversion to/from interface types is
9016 -- always valid
9021 -- If the operand is a class-wide type obtained through a limited_
9022 -- with clause, and the context includes the non-limited view, use
9023 -- it to determine whether the conversion is legal.
9029 then
9034 then
9037 else
9038 Error_Msg_NE
9045 -- Start of processing for Valid_Conversion
9047 begin
9051 declare
9058 begin
9059 -- Remove procedure calls, which syntactically cannot appear
9060 -- in this context, but which cannot be removed by type checking,
9061 -- because the context does not impose a type.
9063 -- When compiling for VMS, spurious ambiguities can be produced
9064 -- when arithmetic operations have a literal operand and return
9065 -- System.Address or a descendant of it. These ambiguities are
9066 -- otherwise resolved by the context, but for conversions there
9067 -- is no context type and the removal of the spurious operations
9068 -- must be done explicitly here.
9070 -- The node may be labelled overloaded, but still contain only
9071 -- one interpretation because others were discarded in previous
9072 -- filters. If this is the case, retain the single interpretation
9073 -- if legal.
9081 then
9082 -- More than one candidate interpretation is available
9092 then
9133 -- Numeric types
9137 -- A universal fixed expression can be converted to any numeric type
9142 -- Also no need to check when in an instance or inlined body, because
9143 -- the legality has been established when the template was analyzed.
9144 -- Furthermore, numeric conversions may occur where only a private
9145 -- view of the operand type is visible at the instantiation point.
9146 -- This results in a spurious error if we check that the operand type
9147 -- is a numeric type.
9149 -- Note: in a previous version of this unit, the following tests were
9150 -- applied only for generated code (Comes_From_Source set to False),
9151 -- but in fact the test is required for source code as well, since
9152 -- this situation can arise in source code.
9157 -- Otherwise we need the conversion check
9159 else
9160 return Conversion_Check
9165 -- Array types
9171 then
9172 Error_Msg_N
9175 else
9179 -- Ada 2005 (AI-251): Anonymous access types where target references an
9180 -- interface type.
9183 or else
9186 then
9187 -- Check the static accessibility rule of 4.6(17). Note that the
9188 -- check is not enforced when within an instance body, since the RM
9189 -- requires such cases to be caught at run time.
9194 then
9195 -- In an instance, this is a run-time check, but one we know
9196 -- will fail, so generate an appropriate warning. The raise
9197 -- will be generated by Expand_N_Type_Conversion.
9200 Error_Msg_N
9202 Operand);
9203 Error_Msg_N
9205 else
9206 Error_Msg_N
9208 Operand);
9212 -- Special accessibility checks are needed in the case of access
9213 -- discriminants declared for a limited type.
9217 then
9218 -- When the operand is a selected access discriminant the check
9219 -- needs to be made against the level of the object denoted by
9220 -- the prefix of the selected name. (Object_Access_Level
9221 -- handles checking the prefix of the operand for this case.)
9226 then
9227 -- In an instance, this is a run-time check, but one we
9228 -- know will fail, so generate an appropriate warning.
9229 -- The raise will be generated by Expand_N_Type_Conversion.
9232 Error_Msg_N
9235 Error_Msg_N
9237 else
9238 Error_Msg_N
9245 -- The case of a reference to an access discriminant from
9246 -- within a limited type declaration (which will appear as
9247 -- a discriminal) is always illegal because the level of the
9248 -- discriminant is considered to be deeper than any (nameable)
9249 -- access type.
9256 then
9257 Error_Msg_N
9259 Operand);
9267 -- General and anonymous access types
9271 and then
9272 Conversion_Check
9275 E_Access_Subprogram_Type
9277 E_Access_Protected_Subprogram_Type,
9279 then
9282 then
9283 Error_Msg_N
9288 -- Check the static accessibility rule of 4.6(17). Note that the
9289 -- check is not enforced when within an instance body, since the RM
9290 -- requires such cases to be caught at run time.
9294 then
9297 then
9298 -- In an instance, this is a run-time check, but one we
9299 -- know will fail, so generate an appropriate warning.
9300 -- The raise will be generated by Expand_N_Type_Conversion.
9303 Error_Msg_N
9305 Operand);
9306 Error_Msg_N
9309 else
9310 -- Avoid generation of spurious error message
9313 Error_Msg_N
9315 Operand);
9321 -- Special accessibility checks are needed in the case of access
9322 -- discriminants declared for a limited type.
9326 then
9328 -- When the operand is a selected access discriminant the check
9329 -- needs to be made against the level of the object denoted by
9330 -- the prefix of the selected name. (Object_Access_Level
9331 -- handles checking the prefix of the operand for this case.)
9336 then
9337 -- In an instance, this is a run-time check, but one we
9338 -- know will fail, so generate an appropriate warning.
9339 -- The raise will be generated by Expand_N_Type_Conversion.
9342 Error_Msg_N
9345 Error_Msg_N
9347 Operand);
9349 else
9350 Error_Msg_N
9357 -- The case of a reference to an access discriminant from
9358 -- within a limited type declaration (which will appear as
9359 -- a discriminal) is always illegal because the level of the
9360 -- discriminant is considered to be deeper than any (nameable)
9361 -- access type.
9367 then
9368 Error_Msg_N
9370 Operand);
9376 declare
9378 -- Helper function to handle limited views
9380 --------------------------
9381 -- Full_Designated_Type --
9382 --------------------------
9386 begin
9390 then
9392 else
9403 begin
9407 else
9409 Error_Msg_NE
9414 -- Ada 2005 AI-384: legality rule is symmetric in both
9415 -- designated types. The conversion is legal (with possible
9416 -- constraint check) if either designated type is
9417 -- unconstrained.
9420 or else
9422 and then
9425 then
9428 else
9429 Error_Msg_NE
9437 -- Access to subprogram types. If the operand is an access parameter,
9438 -- the type has a deeper accessibility that any master, and cannot
9439 -- be assigned.
9442 or else
9445 then
9449 then
9450 Error_Msg_N
9452 Operand);
9453 Error_Msg_N
9456 Operand);
9458 Error_Msg_NE
9463 -- Check that the designated types are subtype conformant
9469 -- Check the static accessibility rule of 4.6(20)
9473 then
9474 Error_Msg_N
9476 Operand);
9478 -- Check that if the operand type is declared in a generic body,
9479 -- then the target type must be declared within that same body
9480 -- (enforces last sentence of 4.6(20)).
9483 declare
9489 begin
9496 Error_Msg_N
9505 -- Remote subprogram access types
9509 then
9510 -- It is valid to convert from one RAS type to another provided
9511 -- that their specification statically match.
9513 Check_Subtype_Conformant
9516 Old_Id =>
9518 Err_Loc =>
9519 N);
9522 -- If both are tagged types, check legality of view conversions
9526 then
9529 -- Types derived from the same root type are convertible
9534 -- In an instance or an inlined body, there may be inconsistent
9535 -- views of the same type, or of types derived from a common root.
9538 and then
9541 then
9544 -- Special check for common access type error case
9548 then
9554 else