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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 ------------------------------------------------------------------------------
80 -----------------------
81 -- Local Subprograms --
82 -----------------------
84 -- Second pass (top-down) type checking and overload resolution procedures
85 -- Typ is the type required by context. These procedures propagate the
86 -- type information recursively to the descendants of N. If the node
87 -- is not overloaded, its Etype is established in the first pass. If
88 -- overloaded, the Resolve routines set the correct type. For arith.
89 -- operators, the Etype is the base type of the context.
91 -- Note that Resolve_Attribute is separated off in Sem_Attr
94 -- Enforce the restrictions on the use of discriminants when constraining
95 -- a component of a discriminated type (record or concurrent type).
98 -- Given a node for an operator associated with type T, check that
99 -- the operator is visible. Operators all of whose operands are
100 -- universal must be checked for visibility during resolution
101 -- because their type is not determinable based on their operands.
103 procedure Check_Fully_Declared_Prefix
106 -- Check that the type of the prefix of a dereference is not incomplete
109 -- Given a call node, N, which is known to occur immediately within the
110 -- subprogram being called, determines whether it is a detectable case of
111 -- an infinite recursion, and if so, outputs appropriate messages. Returns
112 -- True if an infinite recursion is detected, and False otherwise.
115 -- If the type of the object being initialized uses the secondary stack
116 -- directly or indirectly, create a transient scope for the call to the
117 -- init proc. This is because we do not create transient scopes for the
118 -- initialization of individual components within the init proc itself.
119 -- Could be optimized away perhaps?
122 -- Determine whether E is an access type declared by an access
123 -- declaration, and not an (anonymous) allocator type.
126 -- Utility to check whether the name in the call is a predefined
127 -- operator, in which case the call is made into an operator node.
128 -- An instance of an intrinsic conversion operation may be given
129 -- an operator name, but is not treated like an operator.
132 -- If a default expression in entry call N depends on the discriminants
133 -- of the task, it must be replaced with a reference to the discriminant
134 -- of the task being called.
136 procedure Resolve_Op_Concat_Arg
141 -- Internal procedure for Resolve_Op_Concat to resolve one operand of
142 -- concatenation operator. The operand is either of the array type or of
143 -- the component type. If the operand is an aggregate, and the component
144 -- type is composite, this is ambiguous if component type has aggregates.
147 -- Does the first part of the work of Resolve_Op_Concat
150 -- Does the "rest" of the work of Resolve_Op_Concat, after the left operand
151 -- has been resolved. See Resolve_Op_Concat for details.
186 function Operator_Kind
189 -- Utility to map the name of an operator into the corresponding Node. Used
190 -- by other node rewriting procedures.
193 -- Resolve actuals of call, and add default expressions for missing ones.
194 -- N is the Node_Id for the subprogram call, and Nam is the entity of the
195 -- called subprogram.
198 -- Called from Resolve_Call, when the prefix denotes an entry or element
199 -- of entry family. Actuals are resolved as for subprograms, and the node
200 -- is rebuilt as an entry call. Also called for protected operations. Typ
201 -- is the context type, which is used when the operation is a protected
202 -- function with no arguments, and the return value is indexed.
205 -- A call to a user-defined intrinsic operator is rewritten as a call
206 -- to the corresponding predefined operator, with suitable conversions.
209 -- Ditto, for unary operators (only arithmetic ones)
212 -- If an operator node resolves to a call to a user-defined operator,
213 -- rewrite the node as a function call.
215 procedure Make_Call_Into_Operator
219 -- Inverse transformation: if an operator is given in functional notation,
220 -- then after resolving the node, transform into an operator node, so
221 -- that operands are resolved properly. Recall that predefined operators
222 -- do not have a full signature and special resolution rules apply.
224 procedure Rewrite_Renamed_Operator
228 -- An operator can rename another, e.g. in an instantiation. In that
229 -- case, the proper operator node must be constructed and resolved.
232 -- The String_Literal_Subtype is built for all strings that are not
233 -- operands of a static concatenation operation. If the argument is
234 -- not a N_String_Literal node, then the call has no effect.
237 -- Build subtype of array type, with the range specified by the slice
240 -- Called after N has been resolved and evaluated, but before range checks
241 -- have been applied. Currently simplifies a combination of floating-point
242 -- to integer conversion and Truncation attribute.
245 -- A universal_fixed expression in an universal context is unambiguous
246 -- if there is only one applicable fixed point type. Determining whether
247 -- there is only one requires a search over all visible entities, and
248 -- happens only in very pathological cases (see 6115-006).
250 function Valid_Conversion
254 -- Verify legality rules given in 4.6 (8-23). Target is the target
255 -- type of the conversion, which may be an implicit conversion of
256 -- an actual parameter to an anonymous access type (in which case
257 -- N denotes the actual parameter and N = Operand).
259 -------------------------
260 -- Ambiguous_Character --
261 -------------------------
266 begin
270 -- First the ones in Standard
272 Error_Msg_N
274 Error_Msg_N
277 -- Include Wide_Wide_Character in Ada 2005 mode
280 Error_Msg_N
284 -- Now any other types that match
294 -------------------------
295 -- Analyze_And_Resolve --
296 -------------------------
299 begin
305 begin
310 -- Version withs check(s) suppressed
312 procedure Analyze_And_Resolve
316 is
319 begin
321 declare
323 begin
329 else
330 declare
333 begin
341 and then Scope_Is_Transient
342 then
343 -- This can only happen if a transient scope was created
344 -- for an inner expression, which will be removed upon
345 -- completion of the analysis of an enclosing construct.
346 -- The transient scope must have the suppress status of
347 -- the enclosing environment, not of this Analyze call.
350 Scope_Suppress;
354 procedure Analyze_And_Resolve
357 is
360 begin
362 declare
364 begin
370 else
371 declare
374 begin
382 and then Scope_Is_Transient
383 then
385 Scope_Suppress;
389 ----------------------------
390 -- Check_Discriminant_Use --
391 ----------------------------
399 begin
400 -- Any use in a spec-expression is legal
407 -- Discriminant cannot be used to constrain a scalar type
414 then
419 -- The following check catches the unusual case where
420 -- a discriminant appears within an index constraint
421 -- that is part of a larger expression within a constraint
422 -- on a component, e.g. "C : Int range 1 .. F (new A(1 .. D))".
423 -- For now we only check case of record components, and
424 -- note that a similar check should also apply in the
425 -- case of discriminant constraints below. ???
427 -- Note that the check for N_Subtype_Declaration below is to
428 -- detect the valid use of discriminants in the constraints of a
429 -- subtype declaration when this subtype declaration appears
430 -- inside the scope of a record type (which is syntactically
431 -- illegal, but which may be created as part of derived type
432 -- processing for records). See Sem_Ch3.Build_Derived_Record_Type
433 -- for more info.
437 and then not
439 and then
441 N_Subtype_Declaration)
443 then
444 Error_Msg_N
449 -- Detect a common beginner error:
451 -- type R (D : Positive := 100) is record
452 -- Name : String (1 .. D);
453 -- end record;
455 -- The default value causes an object of type R to be
456 -- allocated with room for Positive'Last characters.
458 declare
465 -- Return True if type T has a large enough range that
466 -- any array whose index type covered the whole range of
467 -- the type would likely raise Storage_Error.
469 ------------------------
470 -- Large_Storage_Type --
471 ------------------------
474 begin
475 -- The type is considered large if its bounds are known at
476 -- compile time and if it requires at least as many bits as
477 -- a Positive to store the possible values.
481 and then
486 begin
487 -- Check that the Disc has a large range
493 -- If the enclosing type is limited, we allocate only the
494 -- default value, not the maximum, and there is no need for
495 -- a warning.
501 -- Check that it is the high bound
505 then
509 -- Check the array allows a large range at this bound.
510 -- First find the array
524 -- Next, find the dimension
532 loop
541 -- Now, check the dimension has a large range
547 -- Warn about the danger
549 Error_Msg_N
559 -- Legal case is in index or discriminant constraint
562 N_Discriminant_Association)
563 then
565 Error_Msg_N
570 then
571 Error_Msg_N
577 -- Otherwise, context is an expression. It should not be within
578 -- (i.e. a subexpression of) a constraint for a component.
580 else
584 N_Subtype_Indication,
585 N_Entry_Declaration)
586 loop
592 -- If the discriminant is used in an expression that is a bound
593 -- of a scalar type, an Itype is created and the bounds are attached
594 -- to its range, not to the original subtype indication. Such use
595 -- is of course a double fault.
599 N_Derived_Type_Definition)
602 -- The constraint itself may be given by a subtype indication,
603 -- rather than by a more common discrete range.
606 and then
610 then
611 Error_Msg_N
617 --------------------------------
618 -- Check_For_Visible_Operator --
619 --------------------------------
622 begin
624 Error_Msg_NE
630 ----------------------------------
631 -- Check_Fully_Declared_Prefix --
632 ----------------------------------
634 procedure Check_Fully_Declared_Prefix
637 is
638 begin
639 -- Check that the designated type of the prefix of a dereference is
640 -- not an incomplete type. This cannot be done unconditionally, because
641 -- dereferences of private types are legal in default expressions. This
642 -- case is taken care of in Check_Fully_Declared, called below. There
643 -- are also 2005 cases where it is legal for the prefix to be unfrozen.
645 -- This consideration also applies to similar checks for allocators,
646 -- qualified expressions, and type conversions.
648 -- An additional exception concerns other per-object expressions that
649 -- are not directly related to component declarations, in particular
650 -- representation pragmas for tasks. These will be per-object
651 -- expressions if they depend on discriminants or some global entity.
652 -- If the task has access discriminants, the designated type may be
653 -- incomplete at the point the expression is resolved. This resolution
654 -- takes place within the body of the initialization procedure, where
655 -- the discriminant is replaced by its discriminal.
659 then
662 -- Ada 2005 (AI-326): Tagged incomplete types allowed. The wrong usages
663 -- are handled by Analyze_Access_Attribute, Analyze_Assignment,
664 -- Analyze_Object_Renaming, and Freeze_Entity.
669 E_Incomplete_Type
671 then
673 else
678 ------------------------------
679 -- Check_Infinite_Recursion --
680 ------------------------------
687 -- Check whether list of actuals is identical to list of formals
688 -- of called function (which is also the enclosing scope).
690 ------------------------
691 -- Same_Argument_List --
692 ------------------------
699 begin
702 else
711 then
722 -- Start of processing for Check_Infinite_Recursion
724 begin
725 -- Special case, if this is a procedure call and is a call to the
726 -- current procedure with the same argument list, then this is for
727 -- sure an infinite recursion and we insert a call to raise SE.
731 and then Same_Argument_List
732 then
733 declare
735 begin
739 then
750 -- If not that special case, search up tree, quitting if we reach a
751 -- construct (e.g. a conditional) that tells us that this is not a
752 -- case for an infinite recursion warning.
755 loop
759 N_And_Then,
760 N_If_Statement,
761 N_Case_Statement)
762 then
767 then
768 -- If the call is the expression of a return statement and the
769 -- actuals are identical to the formals, it's worth a warning.
770 -- However, we skip this if there is an immediately preceding
771 -- raise statement, since the call is never executed.
773 -- Furthermore, this corresponds to a common idiom:
775 -- function F (L : Thing) return Boolean is
776 -- begin
777 -- raise Program_Error;
778 -- return F (L);
779 -- end F;
781 -- for generating a stub function
784 and then Same_Argument_List
785 then
788 -- OK, return statement is in a statement list, look for raise
790 declare
793 begin
794 -- Skip past N_Freeze_Entity nodes generated by expansion
799 loop
803 -- If no raise statement, give warning
806 and then
814 else
825 -------------------------------
826 -- Check_Initialization_Call --
827 -------------------------------
833 -- Check whether the creation of an object of the type will involve
834 -- use of the secondary stack. If T is a record type, this is true
835 -- if the expression for some component uses the secondary stack, e.g.
836 -- through a call to a function that returns an unconstrained value.
837 -- False if T is controlled, because cleanups occur elsewhere.
839 -------------
840 -- Uses_SS --
841 -------------
848 begin
849 -- Normally we want to use the underlying type, but if it's not set
850 -- then continue with T.
867 then
868 -- The expression for a dynamic component may be rewritten
869 -- as a dereference, so retrieve original node.
873 -- Return True if the expression is a call to a function
874 -- (including an attribute function such as Image) with
875 -- a result that requires a transient scope.
881 then
894 else
899 -- Start of processing for Check_Initialization_Call
901 begin
902 -- Establish a transient scope if the type needs it
909 ------------------------------
910 -- Check_Parameterless_Call --
911 ------------------------------
917 -- If the prefix is of an access_to_subprogram type, the node must be
918 -- rewritten as a call. Ditto if the prefix is overloaded and all its
919 -- interpretations are access to subprograms.
921 ---------------------------
922 -- Prefix_Is_Access_Subp --
923 ---------------------------
929 begin
931 return
934 else
939 then
950 -- Start of processing for Check_Parameterless_Call
952 begin
953 -- Defend against junk stuff if errors already detected
960 then
967 -- If the context expects a value, and the name is a procedure, this is
968 -- most likely a missing 'Access. Don't try to resolve the parameterless
969 -- call, error will be caught when the outer call is analyzed.
974 and then
976 N_Function_Call,
977 N_Procedure_Call_Statement)
978 then
982 -- Rewrite as call if overloadable entity that is (or could be, in the
983 -- overloaded case) a function call. If we know for sure that the entity
984 -- is an enumeration literal, we do not rewrite it.
991 -- Rewrite as call if it is an explicit deference of an expression of
992 -- a subprogram access type, and the subprogram type is not that of a
993 -- procedure or entry.
995 or else
998 -- Rewrite as call if it is a selected component which is a function,
999 -- this is the case of a call to a protected function (which may be
1000 -- overloaded with other protected operations).
1002 or else
1005 or else
1007 or else
1011 -- If one of the above three conditions is met, rewrite as call.
1012 -- Apply the rewriting only once.
1014 then
1017 then
1020 -- If overloaded, overload set belongs to new copy
1024 -- Change node to parameterless function call (note that the
1025 -- Parameter_Associations associations field is left set to Empty,
1026 -- its normal default value since there are no parameters)
1039 -----------------------------
1040 -- Is_Definite_Access_Type --
1041 -----------------------------
1045 begin
1051 ----------------------
1052 -- Is_Predefined_Op --
1053 ----------------------
1056 begin
1064 -----------------------------
1065 -- Make_Call_Into_Operator --
1066 -----------------------------
1068 procedure Make_Call_Into_Operator
1072 is
1087 -- If the operand is not universal, and the operator is given by a
1088 -- expanded name, verify that the operand has an interpretation with
1089 -- a type defined in the given scope of the operator.
1092 -- Find a type of the given class in the package Pack that contains
1093 -- the operator.
1095 ---------------------------
1096 -- Operand_Type_In_Scope --
1097 ---------------------------
1104 begin
1108 else
1122 ---------------
1123 -- Type_In_P --
1124 ---------------
1130 -- Verify that node is not part of the type declaration for the
1131 -- candidate type, which would otherwise be invisible.
1133 -------------
1134 -- In_Decl --
1135 -------------
1141 begin
1150 else
1153 loop
1156 else
1165 -- Start of processing for Type_In_P
1167 begin
1168 -- If the context type is declared in the prefix package, this
1169 -- is the desired base type.
1173 then
1176 else
1180 and then not In_Decl
1181 then
1192 -- Start of processing for Make_Call_Into_Operator
1194 begin
1197 -- Binary operator
1207 -- Unary operator
1209 else
1215 -- If the operator is denoted by an expanded name, and the prefix is
1216 -- not Standard, but the operator is a predefined one whose scope is
1217 -- Standard, then this is an implicit_operator, inserted as an
1218 -- interpretation by the procedure of the same name. This procedure
1219 -- overestimates the presence of implicit operators, because it does
1220 -- not examine the type of the operands. Verify now that the operand
1221 -- type appears in the given scope. If right operand is universal,
1222 -- check the other operand. In the case of concatenation, either
1223 -- argument can be the component type, so check the type of the result.
1224 -- If both arguments are literals, look for a type of the right kind
1225 -- defined in the given scope. This elaborate nonsense is brought to
1226 -- you courtesy of b33302a. The type itself must be frozen, so we must
1227 -- find the type of the proper class in the given scope.
1229 -- A final wrinkle is the multiplication operator for fixed point
1230 -- types, which is defined in Standard only, and not in the scope of
1231 -- the fixed_point type itself.
1236 -- If the entity being called is defined in the given package,
1237 -- it is a renaming of a predefined operator, and known to be
1238 -- legal.
1242 then
1245 -- Visibility does not need to be checked in an instance: if the
1246 -- operator was not visible in the generic it has been diagnosed
1247 -- already, else there is an implicit copy of it in the instance.
1256 then
1261 -- Ada 2005, AI-420: Predefined equality on Universal_Access
1262 -- is available.
1267 then
1270 else
1279 and then Is_Binary
1281 then
1287 -- Verify that the scope contains a type that corresponds to
1288 -- the given literal. Optimize the case where Pack is Standard.
1310 else
1319 else
1328 then
1331 -- If the type is defined elsewhere, and the operator is not
1332 -- defined in the given scope (by a renaming declaration, e.g.)
1333 -- then this is an error as well. If an extension of System is
1334 -- present, and the type may be defined there, Pack must be
1335 -- System itself.
1342 then
1345 else
1351 then
1358 Error_Msg_NE
1369 else
1373 -- If this is a call to a function that renames a predefined equality,
1374 -- the renaming declaration provides a type that must be used to
1375 -- resolve the operands. This must be done now because resolution of
1376 -- the equality node will not resolve any remaining ambiguity, and it
1377 -- assumes that the first operand is not overloaded.
1382 then
1390 -- Do rewrite setting Comes_From_Source on the result if the original
1391 -- call came from source. Although it is not strictly the case that the
1392 -- operator as such comes from the source, logically it corresponds
1393 -- exactly to the function call in the source, so it should be marked
1394 -- this way (e.g. to make sure that validity checks work fine).
1396 declare
1398 begin
1403 -- If this is an arithmetic operator and the result type is private,
1404 -- the operands and the result must be wrapped in conversion to
1405 -- expose the underlying numeric type and expand the proper checks,
1406 -- e.g. on division.
1410 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
1411 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
1420 else
1424 -- For predefined operators on literals, the operation freezes
1425 -- their type.
1433 -------------------
1434 -- Operator_Kind --
1435 -------------------
1437 function Operator_Kind
1440 is
1443 begin
1479 else
1483 -- Unary operators
1485 else
1494 else
1502 ----------------------------
1503 -- Preanalyze_And_Resolve --
1504 ----------------------------
1509 begin
1513 -- We suppress all checks for this analysis, since the checks will
1514 -- be applied properly, and in the right location, when the default
1515 -- expression is reanalyzed and reexpanded later on.
1519 Expander_Mode_Restore;
1523 -- Version without context type
1528 begin
1535 Expander_Mode_Restore;
1539 ----------------------------------
1540 -- Replace_Actual_Discriminants --
1541 ----------------------------------
1549 -------------------
1550 -- Process_Discr --
1551 -------------------
1556 begin
1562 then
1578 -- Start of processing for Replace_Actual_Discriminants
1580 begin
1594 else
1599 -------------
1600 -- Resolve --
1601 -------------
1617 -- Determine whether a node comes from a predefined library unit or
1618 -- Standard.
1621 -- Try and fix up a literal so that it matches its expected type. New
1622 -- literals are manufactured if necessary to avoid cascaded errors.
1625 -- Called when attempt at resolving current expression fails
1627 ------------------------------------
1628 -- Comes_From_Predefined_Lib_Unit --
1629 -------------------------------------
1632 begin
1633 return
1639 --------------------
1640 -- Patch_Up_Value --
1641 --------------------
1644 begin
1647 then
1656 then
1665 then
1670 Char_Literal_Value =>
1677 then
1688 -----------------------
1689 -- Resolution_Failed --
1690 -----------------------
1693 begin
1699 -- The caller will return without calling the expander, so we need
1700 -- to set the analyzed flag. Note that it is fine to set Analyzed
1701 -- to True even if we are in the middle of a shallow analysis,
1702 -- (see the spec of sem for more details) since this is an error
1703 -- situation anyway, and there is no point in repeating the
1704 -- analysis later (indeed it won't work to repeat it later, since
1705 -- we haven't got a clear resolution of which entity is being
1706 -- referenced.)
1712 -- Start of processing for Resolve
1714 begin
1719 -- Access attribute on remote subprogram cannot be used for
1720 -- a non-remote access-to-subprogram type.
1731 then
1732 Error_Msg_N
1738 -- If the context is a Remote_Access_To_Subprogram, access attributes
1739 -- must be resolved with the corresponding fat pointer. There is no need
1740 -- to check for the attribute name since the return type of an
1741 -- attribute is never a remote type.
1747 then
1748 declare
1756 begin
1757 -- Check that Typ is a remote access-to-subprogram type
1760 -- Prefix (N) must statically denote a remote subprogram
1761 -- declared in a package specification.
1778 or else
1780 then
1782 Error_Msg_N
1784 N);
1788 -- If we are generating code for a distributed program.
1789 -- perform semantic checks against the corresponding
1790 -- remote entities.
1795 and then Expander_Active
1797 then
1798 Check_Subtype_Conformant
1800 Old_Id => Designated_Type
1821 then
1826 -- Return if already analyzed
1832 -- Return if type = Any_Type (previous error encountered)
1841 -- If not overloaded, then we know the type, and all that needs doing
1842 -- is to check that this type is compatible with the context.
1848 -- In the overloaded case, we must select the interpretation that
1849 -- is compatible with the context (i.e. the type passed to Resolve)
1851 else
1852 -- Loop through possible interpretations
1857 -- We are only interested in interpretations that are compatible
1858 -- with the expected type, any other interpretations are ignored.
1863 Write_Eol;
1866 else
1867 -- Skip the current interpretation if it is disabled by an
1868 -- abstract operator. This action is performed only when the
1869 -- type against which we are resolving is the same as the
1870 -- type of the interpretation.
1877 then
1881 -- First matching interpretation
1889 -- Matching interpretation that is not the first, maybe an
1890 -- error, but there are some cases where preference rules are
1891 -- used to choose between the two possibilities. These and
1892 -- some more obscure cases are handled in Disambiguate.
1894 else
1895 -- If the current statement is part of a predefined library
1896 -- unit, then all interpretations which come from user level
1897 -- packages should not be considered.
1899 if From_Lib
1901 then
1908 -- Disambiguation has succeeded. Skip the remaining
1909 -- interpretations.
1919 else
1920 -- Before we issue an ambiguity complaint, check for
1921 -- the case of a subprogram call where at least one
1922 -- of the arguments is Any_Type, and if so, suppress
1923 -- the message, since it is a cascaded error.
1926 N_Procedure_Call_Statement)
1927 then
1928 declare
1932 begin
1944 Write_Eol;
1957 then
1962 then
1966 -- Not that special case, so issue message using the
1967 -- flag Ambiguous to control printing of the header
1968 -- message only at the start of an ambiguous set.
1973 then
1974 Error_Msg_N
1977 else
1978 Error_Msg_NE
1986 Error_Msg_N
1988 else
1995 -- By default, the error message refers to the candidate
1996 -- interpretation. But if it is a predefined operator, it
1997 -- is implicitly declared at the declaration of the type
1998 -- of the operand. Recover the sloc of that declaration
1999 -- for the error message.
2005 Standard_Standard
2006 then
2011 then
2019 Standard_Standard
2020 then
2025 then
2029 -- If this is an indirect call, use the subprogram_type
2030 -- in the message, to have a meaningful location.
2031 -- Indicate as well if this is an inherited operation,
2032 -- created by a type declaration.
2037 then
2039 Error_Msg_Sloc :=
2041 else
2048 then
2049 -- Special-case the message for universal_fixed
2050 -- operators, which are not declared with the type
2051 -- of the operand, but appear forever in Standard.
2055 then
2056 Error_Msg_N
2060 else
2061 Error_Msg_N
2065 elsif
2067 then
2068 Error_Msg_N
2070 else
2077 -- We have a matching interpretation, Expr_Type is the type
2078 -- from this interpretation, and Seen is the entity.
2080 -- For an operator, just set the entity name. The type will be
2081 -- set by the specific operator resolution routine.
2090 -- For an explicit dereference, attribute reference, range,
2091 -- short-circuit form (which is not an operator node), or call
2092 -- with a name that is an explicit dereference, there is
2093 -- nothing to be done at this point.
2096 N_Attribute_Reference,
2097 N_And_Then,
2098 N_Indexed_Component,
2099 N_Or_Else,
2100 N_Range,
2101 N_Selected_Component,
2102 N_Slice)
2104 then
2107 -- For procedure or function calls, set the type of the name,
2108 -- and also the entity pointer for the prefix
2113 then
2120 then
2125 -- For all other cases, just set the type of the Name
2127 else
2135 -- Move to next interpretation
2143 -- At this stage Found indicates whether or not an acceptable
2144 -- interpretation exists. If not, then we have an error, except
2145 -- that if the context is Any_Type as a result of some other error,
2146 -- then we suppress the error report.
2151 -- If type we are looking for is Void, then this is the procedure
2152 -- call case, and the error is simply that what we gave is not a
2153 -- procedure name (we think of procedure calls as expressions with
2154 -- types internally, but the user doesn't think of them this way!)
2158 -- Special case message if function used as a procedure
2163 then
2164 Error_Msg_NE
2168 -- Otherwise give general message (not clear what cases this
2169 -- covers, but no harm in providing for them!)
2171 else
2177 -- Otherwise we do have a subexpression with the wrong type
2179 -- Check for the case of an allocator which uses an access type
2180 -- instead of the designated type. This is a common error and we
2181 -- specialize the message, posting an error on the operand of the
2182 -- allocator, complaining that we expected the designated type of
2183 -- the allocator.
2189 then
2193 -- Check for view mismatch on Null in instances, for which the
2194 -- view-swapping mechanism has no identifier.
2200 then
2205 -- Check for an aggregate. Sometimes we can get bogus aggregates
2206 -- from misuse of parentheses, and we are about to complain about
2207 -- the aggregate without even looking inside it.
2209 -- Instead, if we have an aggregate of type Any_Composite, then
2210 -- analyze and resolve the component fields, and then only issue
2211 -- another message if we get no errors doing this (otherwise
2212 -- assume that the errors in the aggregate caused the problem).
2216 then
2217 -- Disable expansion in any case. If there is a type mismatch
2218 -- it may be fatal to try to expand the aggregate. The flag
2219 -- would otherwise be set to false when the error is posted.
2223 declare
2225 -- Check one aggregate, and set Found to True if we have a
2226 -- definite error in any of its elements
2229 -- Check one element of aggregate and set Found to True if
2230 -- we definitely have an error in the element.
2232 ----------------
2233 -- Check_Aggr --
2234 ----------------
2239 begin
2252 -- If this is a default-initialized component, then
2253 -- there is nothing to check. The box will be
2254 -- replaced by the appropriate call during late
2255 -- expansion.
2266 ----------------
2267 -- Check_Elmt --
2268 ----------------
2271 begin
2272 -- If we have a nested aggregate, go inside it (to
2273 -- attempt a naked analyze-resolve of the aggregate
2274 -- can cause undesirable cascaded errors). Do not
2275 -- resolve expression if it needs a type from context,
2276 -- as for integer * fixed expression.
2281 else
2286 then
2296 begin
2301 -- If an error message was issued already, Found got reset
2302 -- to True, so if it is still False, issue the standard
2303 -- Wrong_Type message.
2308 then
2309 declare
2311 begin
2317 -- Protected operation: retrieve operation name
2320 else
2330 declare
2334 begin
2341 Error_Msg_NE
2347 else
2350 else
2356 Resolution_Failed;
2359 -- Test if we have more than one interpretation for the context
2362 Resolution_Failed;
2365 -- Here we have an acceptable interpretation for the context
2367 else
2368 -- Propagate type information and normalize tree for various
2369 -- predefined operations. If the context only imposes a class of
2370 -- types, rather than a specific type, propagate the actual type
2371 -- downward.
2378 then
2381 -- Any_Fixed is legal in a real context only if a specific
2382 -- fixed point type is imposed. If Norman Cohen can be
2383 -- confused by this, it deserves a separate message.
2387 then
2394 -- A user-defined operator is transformed into a function call at
2395 -- this point, so that further processing knows that operators are
2396 -- really operators (i.e. are predefined operators). User-defined
2397 -- operators that are intrinsic are just renamings of the predefined
2398 -- ones, and need not be turned into calls either, but if they rename
2399 -- a different operator, we must transform the node accordingly.
2400 -- Instantiations of Unchecked_Conversion are intrinsic but are
2401 -- treated as functions, even if given an operator designator.
2406 then
2412 and then
2414 N_Subprogram_Renaming_Declaration
2415 then
2418 -- If the node is rewritten, it will be fully resolved in
2419 -- Rewrite_Renamed_Operator.
2429 when N_Aggregate => Resolve_Aggregate (N, Ctx_Type);
2431 when N_Allocator => Resolve_Allocator (N, Ctx_Type);
2433 when N_And_Then | N_Or_Else
2434 => Resolve_Short_Circuit (N, Ctx_Type);
2436 when N_Attribute_Reference
2437 => Resolve_Attribute (N, Ctx_Type);
2439 when N_Character_Literal
2440 => Resolve_Character_Literal (N, Ctx_Type);
2442 when N_Conditional_Expression
2443 => Resolve_Conditional_Expression (N, Ctx_Type);
2445 when N_Expanded_Name
2446 => Resolve_Entity_Name (N, Ctx_Type);
2448 when N_Extension_Aggregate
2449 => Resolve_Extension_Aggregate (N, Ctx_Type);
2451 when N_Explicit_Dereference
2452 => Resolve_Explicit_Dereference (N, Ctx_Type);
2454 when N_Function_Call
2455 => Resolve_Call (N, Ctx_Type);
2457 when N_Identifier
2458 => Resolve_Entity_Name (N, Ctx_Type);
2460 when N_Indexed_Component
2461 => Resolve_Indexed_Component (N, Ctx_Type);
2463 when N_Integer_Literal
2464 => Resolve_Integer_Literal (N, Ctx_Type);
2466 when N_Membership_Test
2467 => Resolve_Membership_Op (N, Ctx_Type);
2469 when N_Null => Resolve_Null (N, Ctx_Type);
2471 when N_Op_And | N_Op_Or | N_Op_Xor
2472 => Resolve_Logical_Op (N, Ctx_Type);
2474 when N_Op_Eq | N_Op_Ne
2475 => Resolve_Equality_Op (N, Ctx_Type);
2477 when N_Op_Lt | N_Op_Le | N_Op_Gt | N_Op_Ge
2478 => Resolve_Comparison_Op (N, Ctx_Type);
2480 when N_Op_Not => Resolve_Op_Not (N, Ctx_Type);
2482 when N_Op_Add | N_Op_Subtract | N_Op_Multiply |
2483 N_Op_Divide | N_Op_Mod | N_Op_Rem
2485 => Resolve_Arithmetic_Op (N, Ctx_Type);
2487 when N_Op_Concat => Resolve_Op_Concat (N, Ctx_Type);
2489 when N_Op_Expon => Resolve_Op_Expon (N, Ctx_Type);
2491 when N_Op_Plus | N_Op_Minus | N_Op_Abs
2492 => Resolve_Unary_Op (N, Ctx_Type);
2494 when N_Op_Shift => Resolve_Shift (N, Ctx_Type);
2496 when N_Procedure_Call_Statement
2497 => Resolve_Call (N, Ctx_Type);
2499 when N_Operator_Symbol
2500 => Resolve_Operator_Symbol (N, Ctx_Type);
2502 when N_Qualified_Expression
2503 => Resolve_Qualified_Expression (N, Ctx_Type);
2505 when N_Raise_xxx_Error
2506 => Set_Etype (N, Ctx_Type);
2508 when N_Range => Resolve_Range (N, Ctx_Type);
2510 when N_Real_Literal
2511 => Resolve_Real_Literal (N, Ctx_Type);
2513 when N_Reference => Resolve_Reference (N, Ctx_Type);
2515 when N_Selected_Component
2516 => Resolve_Selected_Component (N, Ctx_Type);
2518 when N_Slice => Resolve_Slice (N, Ctx_Type);
2520 when N_String_Literal
2521 => Resolve_String_Literal (N, Ctx_Type);
2523 when N_Subprogram_Info
2524 => Resolve_Subprogram_Info (N, Ctx_Type);
2526 when N_Type_Conversion
2527 => Resolve_Type_Conversion (N, Ctx_Type);
2529 when N_Unchecked_Expression =>
2530 Resolve_Unchecked_Expression (N, Ctx_Type);
2532 when N_Unchecked_Type_Conversion =>
2533 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
2535 end case;
2537 -- If the subexpression was replaced by a non-subexpression, then
2538 -- all we do is to expand it. The only legitimate case we know of
2539 -- is converting procedure call statement to entry call statements,
2540 -- but there may be others, so we are making this test general.
2542 if Nkind (N) not in N_Subexpr then
2543 Debug_A_Exit ("resolving ", N, " (done)");
2544 Expand (N);
2545 return;
2546 end if;
2548 -- The expression is definitely NOT overloaded at this point, so
2549 -- we reset the Is_Overloaded flag to avoid any confusion when
2550 -- reanalyzing the node.
2552 Set_Is_Overloaded (N, False);
2554 -- Freeze expression type, entity if it is a name, and designated
2555 -- type if it is an allocator (RM 13.14(10,11,13)).
2557 -- Now that the resolution of the type of the node is complete,
2558 -- and we did not detect an error, we can expand this node. We
2559 -- skip the expand call if we are in a default expression, see
2560 -- section "Handling of Default Expressions" in Sem spec.
2562 Debug_A_Exit ("resolving ", N, " (done)");
2564 -- We unconditionally freeze the expression, even if we are in
2565 -- default expression mode (the Freeze_Expression routine tests
2566 -- this flag and only freezes static types if it is set).
2568 Freeze_Expression (N);
2570 -- Now we can do the expansion
2572 Expand (N);
2573 end if;
2574 end Resolve;
2576 -------------
2577 -- Resolve --
2578 -------------
2580 -- Version with check(s) suppressed
2582 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
2583 begin
2584 if Suppress = All_Checks then
2585 declare
2586 Svg : constant Suppress_Array := Scope_Suppress;
2587 begin
2588 Scope_Suppress := (others => True);
2589 Resolve (N, Typ);
2590 Scope_Suppress := Svg;
2591 end;
2593 else
2594 declare
2595 Svg : constant Boolean := Scope_Suppress (Suppress);
2596 begin
2597 Scope_Suppress (Suppress) := True;
2598 Resolve (N, Typ);
2599 Scope_Suppress (Suppress) := Svg;
2600 end;
2601 end if;
2602 end Resolve;
2604 -------------
2605 -- Resolve --
2606 -------------
2608 -- Version with implicit type
2610 procedure Resolve (N : Node_Id) is
2611 begin
2612 Resolve (N, Etype (N));
2613 end Resolve;
2615 ---------------------
2616 -- Resolve_Actuals --
2617 ---------------------
2619 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
2620 Loc : constant Source_Ptr := Sloc (N);
2621 A : Node_Id;
2622 F : Entity_Id;
2623 A_Typ : Entity_Id;
2624 F_Typ : Entity_Id;
2625 Prev : Node_Id := Empty;
2626 Orig_A : Node_Id;
2628 procedure Check_Argument_Order;
2629 -- Performs a check for the case where the actuals are all simple
2630 -- identifiers that correspond to the formal names, but in the wrong
2631 -- order, which is considered suspicious and cause for a warning.
2633 procedure Check_Prefixed_Call;
2634 -- If the original node is an overloaded call in prefix notation,
2636 -- Try_Object_Operation has already verified that there is a valid
2637 -- interpretation, but the form of the actual can only be determined
2638 -- once the primitive operation is identified.
2641 -- If the actual is missing in a call, insert in the actuals list
2642 -- an instance of the default expression. The insertion is always
2643 -- a named association.
2646 -- Check whether T1 and T2, or their full views, are derived from a
2647 -- common type. Used to enforce the restrictions on array conversions
2648 -- of AI95-00246.
2650 --------------------------
2651 -- Check_Argument_Order --
2652 --------------------------
2655 begin
2656 -- Nothing to do if no parameters, or original node is neither a
2657 -- function call nor a procedure call statement (happens in the
2658 -- operator-transformed-to-function call case), or the call does
2659 -- not come from source, or this warning is off.
2661 if not Warn_On_Parameter_Order
2662 or else
2664 or else
2666 N_Function_Call)
2667 or else
2669 then
2673 declare
2676 begin
2677 -- Nothing to do if only one parameter
2683 -- Here if at least two arguments
2685 declare
2691 -- Set True if an out of order case is found
2693 begin
2694 -- Collect identifier names of actuals, fail if any actual is
2695 -- not a simple identifier, and record max length of name.
2701 else
2707 -- If we got this far, all actuals are identifiers and the list
2708 -- of their names is stored in the Actuals array.
2713 -- If we ran out of formals, that's odd, probably an error
2714 -- which will be detected elsewhere, but abandon the search.
2720 -- If name matches and is in order OK
2725 else
2726 -- If no match, see if it is elsewhere in list and if so
2727 -- flag potential wrong order if type is compatible.
2731 and then
2733 then
2739 -- No match
2747 -- If Formals left over, also probably an error, skip warning
2753 -- Here we give the warning if something was out of order
2756 Error_Msg_N
2763 -------------------------
2764 -- Check_Prefixed_Call --
2765 -------------------------
2774 begin
2775 -- Check whether the call is a prefixed call, with or without
2776 -- additional actuals.
2779 or else
2785 then
2788 then
2789 -- Introduce dereference on object in prefix
2791 New_A :=
2799 then
2800 -- Introduce an implicit 'Access in prefix
2803 Error_Msg_NE
2819 --------------------
2820 -- Insert_Default --
2821 --------------------
2827 begin
2828 -- Missing argument in call, nothing to insert
2833 else
2834 -- Note that we do a full New_Copy_Tree, so that any associated
2835 -- Itypes are properly copied. This may not be needed any more,
2836 -- but it does no harm as a safety measure! Defaults of a generic
2837 -- formal may be out of bounds of the corresponding actual (see
2838 -- cc1311b) and an additional check may be required.
2840 Actval :=
2841 New_Copy_Tree
2848 then
2854 then
2857 then
2858 -- If default is a real literal, do not introduce a
2859 -- conversion whose effect may depend on the run-time
2860 -- size of universal real.
2864 else
2875 -- Resolve aggregates with their base type, to avoid scope
2876 -- anomalies: the subtype was first built in the subprogram
2877 -- declaration, and the current call may be nested.
2881 then
2883 else
2887 else
2890 -- See note above concerning aggregates
2894 then
2897 -- Resolve entities with their own type, which may differ
2898 -- from the type of a reference in a generic context (the
2899 -- view swapping mechanism did not anticipate the re-analysis
2900 -- of default values in calls).
2905 else
2910 -- If default is a tag indeterminate function call, propagate
2911 -- tag to obtain proper dispatching.
2915 then
2921 -- If the default expression raises constraint error, then just
2922 -- silently replace it with an N_Raise_Constraint_Error node,
2923 -- since we already gave the warning on the subprogram spec.
2933 Assoc :=
2938 -- Case of insertion is first named actual
2942 then
2949 else
2953 else
2957 -- Case of insertion is not first named actual
2959 else
2960 Set_Next_Named_Actual
2972 -------------------
2973 -- Same_Ancestor --
2974 -------------------
2980 begin
2983 then
2989 then
2996 -- Start of processing for Resolve_Actuals
2998 begin
2999 Check_Argument_Order;
3002 Check_Prefixed_Call;
3011 -- If we have an error in any actual or formal, indicated by
3012 -- a type of Any_Type, then abandon resolution attempt, and
3013 -- set result type to Any_Type.
3017 then
3022 -- Case where actual is present
3024 -- If the actual is an entity, generate a reference to it now. We
3025 -- do this before the actual is resolved, because a formal of some
3026 -- protected subprogram, or a task discriminant, will be rewritten
3027 -- during expansion, and the reference to the source entity may
3028 -- be lost.
3033 then
3039 then
3049 or else
3051 then
3052 -- If style checking mode on, check match of formal name
3060 -- If the formal is Out or In_Out, do not resolve and expand the
3061 -- conversion, because it is subsequently expanded into explicit
3062 -- temporaries and assignments. However, the object of the
3063 -- conversion can be resolved. An exception is the case of tagged
3064 -- type conversion with a class-wide actual. In that case we want
3065 -- the tag check to occur and no temporary will be needed (no
3066 -- representation change can occur) and the parameter is passed by
3067 -- reference, so we go ahead and resolve the type conversion.
3068 -- Another exception is the case of reference to component or
3069 -- subcomponent of a bit-packed array, in which case we want to
3070 -- defer expansion to the point the in and out assignments are
3071 -- performed.
3076 then
3079 then
3082 then
3084 -- In a view conversion, the conversion must be legal in
3085 -- both directions, and thus both component types must be
3086 -- aliased, or neither (4.6 (8)).
3088 -- The additional rule 4.6 (24.9.2) seems unduly
3089 -- restrictive: the privacy requirement should not
3090 -- apply to generic types, and should be checked in
3091 -- an instance. ARG query is in order.
3093 Error_Msg_N
3097 elsif
3099 then
3102 then
3103 Error_Msg_N
3106 else
3107 declare
3109 Component_Type
3111 begin
3114 and then
3119 then
3120 Error_Msg_N
3134 then
3138 -- If the actual is a function call that returns a limited
3139 -- unconstrained object that needs finalization, create a
3140 -- transient scope for it, so that it can receive the proper
3141 -- finalization list.
3146 and then Expander_Active
3147 and then
3149 then
3152 else
3156 and then
3159 then
3160 Error_Msg_N
3173 -- (Ada 2005: AI-251): If the actual is an allocator whose
3174 -- directly designated type is a class-wide interface, we build
3175 -- an anonymous access type to use it as the type of the
3176 -- allocator. Later, when the subprogram call is expanded, if
3177 -- the interface has a secondary dispatch table the expander
3178 -- will add a type conversion to force the correct displacement
3179 -- of the pointer.
3182 declare
3188 begin
3191 then
3199 -- Ada 2005, AI-162:If the actual is an allocator, the
3200 -- innermost enclosing statement is the master of the
3201 -- created object. This needs to be done with expansion
3202 -- enabled only, otherwise the transient scope will not
3203 -- be removed in the expansion of the wrapped construct.
3206 and then Expander_Active
3207 then
3213 -- (Ada 2005): The call may be to a primitive operation of
3214 -- a tagged synchronized type, declared outside of the type.
3215 -- In this case the controlling actual must be converted to
3216 -- its corresponding record type, which is the formal type.
3217 -- The actual may be a subtype, either because of a constraint
3218 -- or because it is a generic actual, so use base type to
3219 -- locate concurrent type.
3224 then
3226 Unchecked_Convert_To
3236 -- For mode IN, if actual is an entity, and the type of the formal
3237 -- has warnings suppressed, then we reset Never_Set_In_Source for
3238 -- the calling entity. The reason for this is to catch cases like
3239 -- GNAT.Spitbol.Patterns.Vstring_Var where the called subprogram
3240 -- uses trickery to modify an IN parameter.
3247 then
3251 -- Perform error checks for IN and IN OUT parameters
3255 -- Check unset reference. For scalar parameters, it is clearly
3256 -- wrong to pass an uninitialized value as either an IN or
3257 -- IN-OUT parameter. For composites, it is also clearly an
3258 -- error to pass a completely uninitialized value as an IN
3259 -- parameter, but the case of IN OUT is trickier. We prefer
3260 -- not to give a warning here. For example, suppose there is
3261 -- a routine that sets some component of a record to False.
3262 -- It is perfectly reasonable to make this IN-OUT and allow
3263 -- either initialized or uninitialized records to be passed
3264 -- in this case.
3266 -- For partially initialized composite values, we also avoid
3267 -- warnings, since it is quite likely that we are passing a
3268 -- partially initialized value and only the initialized fields
3269 -- will in fact be read in the subprogram.
3274 then
3278 -- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
3279 -- actual to a nested call, since this is case of reading an
3280 -- out parameter, which is not allowed.
3285 then
3290 -- Case of OUT or IN OUT parameter
3294 -- For an Out parameter, check for useless assignment. Note
3295 -- that we can't set Last_Assignment this early, because we may
3296 -- kill current values in Resolve_Call, and that call would
3297 -- clobber the Last_Assignment field.
3299 -- Note: call Warn_On_Useless_Assignment before doing the check
3300 -- below for Is_OK_Variable_For_Out_Formal so that the setting
3301 -- of Referenced_As_LHS/Referenced_As_Out_Formal properly
3302 -- reflects the last assignment, not this one!
3309 then
3314 -- Validate the form of the actual. Note that the call to
3315 -- Is_OK_Variable_For_Out_Formal generates the required
3316 -- reference in this case.
3322 -- What's the following about???
3326 else
3327 Kill_All_Checks;
3336 -- Apply appropriate range checks for in, out, and in-out
3337 -- parameters. Out and in-out parameters also need a separate
3338 -- check, if there is a type conversion, to make sure the return
3339 -- value meets the constraints of the variable before the
3340 -- conversion.
3342 -- Gigi looks at the check flag and uses the appropriate types.
3343 -- For now since one flag is used there is an optimization which
3344 -- might not be done in the In Out case since Gigi does not do
3345 -- any analysis. More thought required about this ???
3349 then
3361 then
3367 then
3373 then
3376 else
3380 -- Ada 2005 (AI-231)
3386 then
3387 Apply_Compile_Time_Constraint_Error
3397 then
3400 Apply_Scalar_Range_Check
3402 else
3403 Apply_Range_Check
3407 else
3413 then
3416 else
3422 -- An actual associated with an access parameter is implicitly
3423 -- converted to the anonymous access type of the formal and must
3424 -- satisfy the legality checks for access conversions.
3428 Error_Msg_N
3433 -- Check bad case of atomic/volatile argument (RM C.6(12))
3437 then
3440 then
3441 Error_Msg_N
3443 N);
3447 then
3448 Error_Msg_N
3450 N);
3454 -- Check that subprograms don't have improper controlling
3455 -- arguments (RM 3.9.2 (9))
3457 -- A primitive operation may have an access parameter of an
3458 -- incomplete tagged type, but a dispatching call is illegal
3459 -- if the type is still incomplete.
3465 declare
3467 begin
3471 then
3472 Error_Msg_NE
3486 then
3491 then
3493 Error_Msg_NE
3503 and then
3507 then
3508 Error_Msg_N
3513 then
3515 Error_Msg_NE
3522 -- If it is a named association, treat the selector_name as
3523 -- a proper identifier, and mark the corresponding entity.
3540 -- Case where actual is not present
3542 else
3543 Insert_Default;
3550 -----------------------
3551 -- Resolve_Allocator --
3552 -----------------------
3563 procedure Check_Allocator_Discrim_Accessibility
3566 -- Check that accessibility level associated with an access discriminant
3567 -- initialized in an allocator by the expression Disc_Exp is not deeper
3568 -- than the level of the allocator type Alloc_Typ. An error message is
3569 -- issued if this condition is violated. Specialized checks are done for
3570 -- the cases of a constraint expression which is an access attribute or
3571 -- an access discriminant.
3574 -- If the allocator is an actual in a call, it is allowed to be class-
3575 -- wide when the context is not because it is a controlling actual.
3578 -- Propagate all nested coextensions which are located one nesting
3579 -- level down the tree to the node Root. Example:
3580 --
3581 -- Top_Record
3582 -- Level_1_Coextension
3583 -- Level_2_Coextension
3584 --
3585 -- The algorithm is paired with delay actions done by the Expander. In
3586 -- the above example, assume all coextensions are controlled types.
3587 -- The cycle of analysis, resolution and expansion will yield:
3588 --
3589 -- 1) Analyze Top_Record
3590 -- 2) Analyze Level_1_Coextension
3591 -- 3) Analyze Level_2_Coextension
3592 -- 4) Resolve Level_2_Coextension. The allocator is marked as a
3593 -- coextension.
3594 -- 5) Expand Level_2_Coextension. A temporary variable Temp_1 is
3595 -- generated to capture the allocated object. Temp_1 is attached
3596 -- to the coextension chain of Level_2_Coextension.
3597 -- 6) Resolve Level_1_Coextension. The allocator is marked as a
3598 -- coextension. A forward tree traversal is performed which finds
3599 -- Level_2_Coextension's list and copies its contents into its
3600 -- own list.
3601 -- 7) Expand Level_1_Coextension. A temporary variable Temp_2 is
3602 -- generated to capture the allocated object. Temp_2 is attached
3603 -- to the coextension chain of Level_1_Coextension. Currently, the
3604 -- contents of the list are [Temp_2, Temp_1].
3605 -- 8) Resolve Top_Record. A forward tree traversal is performed which
3606 -- finds Level_1_Coextension's list and copies its contents into
3607 -- its own list.
3608 -- 9) Expand Top_Record. Generate finalization calls for Temp_1 and
3609 -- Temp_2 and attach them to Top_Record's finalization list.
3611 -------------------------------------------
3612 -- Check_Allocator_Discrim_Accessibility --
3613 -------------------------------------------
3615 procedure Check_Allocator_Discrim_Accessibility
3618 is
3619 begin
3622 then
3623 Error_Msg_N
3626 -- When the expression is an Access attribute the level of the prefix
3627 -- object must not be deeper than that of the allocator's type.
3631 = Attribute_Access
3634 then
3635 Error_Msg_N
3637 Disc_Exp);
3639 -- When the expression is an access discriminant the check is against
3640 -- the level of the prefix object.
3646 then
3647 Error_Msg_N
3649 Disc_Exp);
3651 -- All other cases are legal
3653 else
3658 ----------------------------
3659 -- In_Dispatching_Context --
3660 ----------------------------
3664 begin
3670 ----------------------------
3671 -- Propagate_Coextensions --
3672 ----------------------------
3677 -- Copy the contents of list From into list To, preserving the
3678 -- order of elements.
3681 -- Recognize an allocator or a rewritten allocator node and add it
3682 -- along with its nested coextensions to the list of Root.
3684 ---------------
3685 -- Copy_List --
3686 ---------------
3690 begin
3698 -----------------------
3699 -- Process_Allocator --
3700 -----------------------
3705 begin
3706 -- This is a possible rewritten subtype indication allocator. Any
3707 -- nested coextensions will appear as discriminant constraints.
3712 then
3713 declare
3717 begin
3719 Discr_Elmt :=
3729 then
3734 Copy_List
3742 -- There is no need to continue the traversal of this
3743 -- subtree since all the information has already been
3744 -- propagated.
3750 -- Case of either a stand alone allocator or a rewritten allocator
3751 -- with an aggregate.
3753 else
3760 -- Propagate the list of nested coextensions to the Root
3761 -- allocator. This is done through list copy since a single
3762 -- allocator may have multiple coextensions. Do not touch
3763 -- coextensions roots.
3767 then
3772 Copy_List
3777 -- There is no need to continue the traversal of this
3778 -- subtree since all the information has already been
3779 -- propagated.
3785 -- Keep on traversing, looking for the next allocator
3793 -- Start of processing for Propagate_Coextensions
3795 begin
3799 -- Start of processing for Resolve_Allocator
3801 begin
3802 -- Replace general access with specific type
3812 -- For qualified expression, resolve the expression using the
3813 -- given subtype (nothing to do for type mark, subtype indication)
3818 and then not In_Dispatching_Context
3819 then
3820 Error_Msg_N
3827 -- A qualified expression requires an exact match of the type,
3828 -- class-wide matching is not allowed.
3833 then
3837 -- A special accessibility check is needed for allocators that
3838 -- constrain access discriminants. The level of the type of the
3839 -- expression used to constrain an access discriminant cannot be
3840 -- deeper than the type of the allocator (in contrast to access
3841 -- parameters, where the level of the actual can be arbitrary).
3843 -- We can't use Valid_Conversion to perform this check because
3844 -- in general the type of the allocator is unrelated to the type
3845 -- of the access discriminant.
3849 then
3856 then
3859 -- Get the first component expression of the aggregate
3869 else
3873 else
3892 else
3897 else
3906 -- For a subtype mark or subtype indication, freeze the subtype
3908 else
3912 Error_Msg_N
3916 -- A special accessibility check is needed for allocators that
3917 -- constrain access discriminants. The level of the type of the
3918 -- expression used to constrain an access discriminant cannot be
3919 -- deeper than the type of the allocator (in contrast to access
3920 -- parameters, where the level of the actual can be arbitrary).
3921 -- We can't use Valid_Conversion to perform this check because
3922 -- in general the type of the allocator is unrelated to the type
3923 -- of the access discriminant.
3928 then
3938 else
3952 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
3953 -- check that the level of the type of the created object is not deeper
3954 -- than the level of the allocator's access type, since extensions can
3955 -- now occur at deeper levels than their ancestor types. This is a
3956 -- static accessibility level check; a run-time check is also needed in
3957 -- the case of an initialized allocator with a class-wide argument (see
3958 -- Expand_Allocator_Expression).
3962 then
3963 declare
3966 begin
3971 else
3980 E);
3986 -- Do not apply Ada 2005 accessibility checks on a class-wide
3987 -- allocator if the type given in the allocator is a formal
3988 -- type. A run-time check will be performed in the instance.
3998 -- Check for allocation from an empty storage pool
4001 declare
4003 begin
4011 -- If the context is an unchecked conversion, as may happen within
4012 -- an inlined subprogram, the allocator is being resolved with its
4013 -- own anonymous type. In that case, if the target type has a specific
4014 -- storage pool, it must be inherited explicitly by the allocator type.
4018 then
4019 Set_Associated_Storage_Pool
4023 -- An erroneous allocator may be rewritten as a raise Program_Error
4024 -- statement.
4028 -- An anonymous access discriminant is the definition of a
4029 -- coextension.
4033 N_Discriminant_Specification
4034 then
4035 -- Avoid marking an allocator as a dynamic coextension if it is
4036 -- within a static construct.
4042 -- Cleanup for potential static coextensions
4044 else
4049 -- There is no need to propagate any nested coextensions if they
4050 -- are marked as static since they will be rewritten on the spot.
4058 ---------------------------
4059 -- Resolve_Arithmetic_Op --
4060 ---------------------------
4062 -- Used for resolving all arithmetic operators except exponentiation
4073 -- We do the resolution using the base type, because intermediate values
4074 -- in expressions always are of the base type, not a subtype of it.
4077 -- Returns True if N is in a context that expects "any real type"
4080 -- Return True iff given type is Integer or universal real/integer
4083 -- Choose type of integer literal in fixed-point operation to conform
4084 -- to available fixed-point type. T is the type of the other operand,
4085 -- which is needed to determine the expected type of N.
4088 -- Set operand type to T if universal
4090 -------------------------------
4091 -- Expected_Type_Is_Any_Real --
4092 -------------------------------
4095 begin
4096 -- N is the expression after "delta" in a fixed_point_definition;
4097 -- see RM-3.5.9(6):
4100 N_Decimal_Fixed_Point_Definition,
4102 -- N is one of the bounds in a real_range_specification;
4103 -- see RM-3.5.7(5):
4105 N_Real_Range_Specification,
4107 -- N is the expression of a delta_constraint;
4108 -- see RM-J.3(3):
4110 N_Delta_Constraint);
4113 -----------------------------
4114 -- Is_Integer_Or_Universal --
4115 -----------------------------
4122 begin
4128 else
4134 then
4145 ----------------------------
4146 -- Set_Mixed_Mode_Operand --
4147 ----------------------------
4153 begin
4156 -- A universal integer literal is resolved as standard integer
4157 -- except in the case of a fixed-point result, where we leave it
4158 -- as universal (to be handled by Exp_Fixd later on)
4162 else
4170 then
4171 -- A universal real can appear in a fixed-type context. We resolve
4172 -- the literal with that context, even though this might raise an
4173 -- exception prematurely (the other operand may be zero).
4180 then
4181 -- Integer arg in mixed-mode operation. Resolve with universal
4182 -- type, in case preference rule must be applied.
4188 then
4189 -- Not a mixed-mode operation, resolve with context
4195 -- N may itself be a mixed-mode operation, so use context type
4202 then
4203 -- Must be (fixed * fixed) operation, operand must have one
4204 -- compatible interpretation.
4212 then
4213 -- C * F(X) in a fixed context, where C is a real literal or a
4214 -- fixed-point expression. F must have either a fixed type
4215 -- interpretation or an integer interpretation, but not both.
4223 else
4231 else
4239 -- Reanalyze the literal with the fixed type of the context. If
4240 -- context is Universal_Fixed, we are within a conversion, leave
4241 -- the literal as a universal real because there is no usable
4242 -- fixed type, and the target of the conversion plays no role in
4243 -- the resolution.
4245 declare
4249 begin
4252 else
4258 then
4260 else
4268 else
4273 ----------------------
4274 -- Set_Operand_Type --
4275 ----------------------
4278 begin
4281 then
4286 -- Start of processing for Resolve_Arithmetic_Op
4288 begin
4293 then
4297 -- Special-case for mixed-mode universal expressions or fixed point
4298 -- type operation: each argument is resolved separately. The same
4299 -- treatment is required if one of the operands of a fixed point
4300 -- operation is universal real, since in this case we don't do a
4301 -- conversion to a specific fixed-point type (instead the expander
4302 -- takes care of the case).
4307 then
4318 or else
4321 then
4326 -- If context is a fixed type and one operand is integer, the
4327 -- other is resolved with the type of the context.
4332 then
4339 then
4343 else
4348 -- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
4349 -- multiplying operators from being used when the expected type is
4350 -- also universal_fixed. Note that B_Typ will be Universal_Fixed in
4351 -- some cases where the expected type is actually Any_Real;
4352 -- Expected_Type_Is_Any_Real takes care of that case.
4356 then
4360 N_Unchecked_Type_Conversion)
4361 then
4368 else
4371 and then not
4373 N_Unchecked_Type_Conversion)
4374 then
4375 Error_Msg_N
4380 -- The expected type is "any real type" in contexts like
4381 -- type T is delta <universal_fixed-expression> ...
4382 -- in which case we need to set the type to Universal_Real
4383 -- so that static expression evaluation will work properly.
4387 else
4397 then
4402 -- If no previous errors, this is only possible if one operand
4403 -- is overloaded and the context is universal. Resolve as such.
4408 else
4410 and then
4412 then
4416 -- If the context is Universal_Fixed and the operands are also
4417 -- universal fixed, this is an error, unless there is only one
4418 -- applicable fixed_point type (usually duration).
4426 else
4431 else
4436 -- If one of the arguments was resolved to a non-universal type.
4437 -- label the result of the operation itself with the same type.
4438 -- Do the same for the universal argument, if any.
4449 -- Set overflow and division checking bit. Much cleverer code needed
4450 -- here eventually and perhaps the Resolve routines should be separated
4451 -- for the various arithmetic operations, since they will need
4452 -- different processing. ???
4459 -- Give warning if explicit division by zero
4463 then
4469 or else
4472 then
4473 -- Specialize the warning message according to the operation
4477 Apply_Compile_Time_Constraint_Error
4482 Apply_Compile_Time_Constraint_Error
4487 Apply_Compile_Time_Constraint_Error
4491 -- Division by zero can only happen with division, rem,
4492 -- and mod operations.
4498 -- Otherwise just set the flag to check at run time
4500 else
4505 -- If Restriction No_Implicit_Conditionals is active, then it is
4506 -- violated if either operand can be negative for mod, or for rem
4507 -- if both operands can be negative.
4511 then
4512 declare
4519 -- Set if corresponding operand might be negative
4521 begin
4529 or else
4531 then
4542 ------------------
4543 -- Resolve_Call --
4544 ------------------
4556 begin
4557 -- The context imposes a unique interpretation with type Typ on a
4558 -- procedure or function call. Find the entity of the subprogram that
4559 -- yields the expected type, and propagate the corresponding formal
4560 -- constraints on the actuals. The caller has established that an
4561 -- interpretation exists, and emitted an error if not unique.
4563 -- First deal with the case of a call to an access-to-subprogram,
4564 -- dereference made explicit in Analyze_Call.
4570 else
4571 -- Find the interpretation whose type (a subprogram type) has a
4572 -- return type that is compatible with the context. Analysis of
4573 -- the node has established that one exists.
4592 -- If the prefix is not an entity, then resolve it
4598 -- For an indirect call, we always invalidate checks, since we do not
4599 -- know whether the subprogram is local or global. Yes we could do
4600 -- better here, e.g. by knowing that there are no local subprograms,
4601 -- but it does not seem worth the effort. Similarly, we kill all
4602 -- knowledge of current constant values.
4604 Kill_Current_Values;
4606 -- If this is a procedure call which is really an entry call, do
4607 -- the conversion of the procedure call to an entry call. Protected
4608 -- operations use the same circuitry because the name in the call
4609 -- can be an arbitrary expression with special resolution rules.
4614 then
4618 -- Kill checks and constant values, as above for indirect case
4619 -- Who knows what happens when another task is activated?
4621 Kill_Current_Values;
4624 -- Normal subprogram call with name established in Resolve
4630 -- Otherwise we must have the case of an overloaded call
4632 else
4648 -- Check that a call to Current_Task does not occur in an entry body
4651 declare
4654 begin
4656 loop
4659 -- Exclude calls that occur within the default of a formal
4660 -- parameter of the entry, since those are evaluated outside
4661 -- of the body.
4668 then
4670 Error_Msg_NE
4673 Error_Msg_NE
4685 -- Check that a procedure call does not occur in the context of the
4686 -- entry call statement of a conditional or timed entry call. Note that
4687 -- the case of a call to a subprogram renaming of an entry will also be
4688 -- rejected. The test for N not being an N_Entry_Call_Statement is
4689 -- defensive, covering the possibility that the processing of entry
4690 -- calls might reach this point due to later modifications of the code
4691 -- above.
4696 then
4700 -- Ada 2005 (AI-345): If a procedure_call_statement is used
4701 -- for a procedure_or_entry_call, the procedure_name or pro-
4702 -- cedure_prefix of the procedure_call_statement shall denote
4703 -- an entry renamed by a procedure, or (a view of) a primitive
4704 -- subprogram of a limited interface whose first parameter is
4705 -- a controlling parameter.
4710 then
4711 Error_Msg_N
4716 -- Check that this is not a call to a protected procedure or
4717 -- entry from within a protected function.
4723 then
4729 -- Freeze the subprogram name if not in a spec-expression. Note that we
4730 -- freeze procedure calls as well as function calls. Procedure calls are
4731 -- not frozen according to the rules (RM 13.14(14)) because it is
4732 -- impossible to have a procedure call to a non-frozen procedure in pure
4733 -- Ada, but in the code that we generate in the expander, this rule
4734 -- needs extending because we can generate procedure calls that need
4735 -- freezing.
4741 -- For a predefined operator, the type of the result is the type imposed
4742 -- by context, except for a predefined operation on universal fixed.
4743 -- Otherwise The type of the call is the type returned by the subprogram
4744 -- being called.
4751 -- If the subprogram returns an array type, and the context requires the
4752 -- component type of that array type, the node is really an indexing of
4753 -- the parameterless call. Resolve as such. A pathological case occurs
4754 -- when the type of the component is an access to the array type. In
4755 -- this case the call is truly ambiguous.
4758 and then
4763 and then
4766 then
4767 declare
4772 begin
4775 then
4776 Error_Msg_N
4778 else
4785 -- Indexed call to a parameterless function
4787 Index_Node :=
4789 Prefix =>
4793 else
4794 -- An Ada 2005 prefixed call to a primitive operation
4795 -- whose first parameter is the prefix. This prefix was
4796 -- prepended to the parameter list, which is actually a
4797 -- list of indices. Remove the prefix in order to build
4798 -- the proper indexed component.
4800 Index_Node :=
4802 Prefix =>
4805 Parameter_Associations =>
4806 New_List
4811 -- Since we are correcting a node classification error made
4812 -- by the parser, we call Replace rather than Rewrite.
4825 else
4829 -- In the case where the call is to an overloaded subprogram, Analyze
4830 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
4831 -- such a case Normalize_Actuals needs to be called once more to order
4832 -- the actuals correctly. Otherwise the call will have the ordering
4833 -- given by the last overloaded subprogram whether this is the correct
4834 -- one being called or not.
4841 -- In any case, call is fully resolved now. Reset Overload flag, to
4842 -- prevent subsequent overload resolution if node is analyzed again
4847 -- If we are calling the current subprogram from immediately within its
4848 -- body, then that is the case where we can sometimes detect cases of
4849 -- infinite recursion statically. Do not try this in case restriction
4850 -- No_Recursion is in effect anyway, and do it only for source calls.
4855 -- Issue warning for possible infinite recursion in the absence
4856 -- of the No_Recursion restriction.
4861 then
4862 -- Here we detected and flagged an infinite recursion, so we do
4863 -- not need to test the case below for further warnings. Also if
4864 -- we now have a raise SE node, we are all done.
4870 -- If call is to immediately containing subprogram, then check for
4871 -- the case of a possible run-time detectable infinite recursion.
4873 else
4877 -- Although in general case, recursion is not statically
4878 -- checkable, the case of calling an immediately containing
4879 -- subprogram is easy to catch.
4883 -- If the recursive call is to a parameterless subprogram,
4884 -- then even if we can't statically detect infinite
4885 -- recursion, this is pretty suspicious, and we output a
4886 -- warning. Furthermore, we will try later to detect some
4887 -- cases here at run time by expanding checking code (see
4888 -- Detect_Infinite_Recursion in package Exp_Ch6).
4890 -- If the recursive call is within a handler, do not emit a
4891 -- warning, because this is a common idiom: loop until input
4892 -- is correct, catch illegal input in handler and restart.
4898 then
4899 -- For the case of a procedure call. We give the message
4900 -- only if the call is the first statement in a sequence
4901 -- of statements, or if all previous statements are
4902 -- simple assignments. This is simply a heuristic to
4903 -- decrease false positives, without losing too many good
4904 -- warnings. The idea is that these previous statements
4905 -- may affect global variables the procedure depends on.
4909 then
4910 declare
4912 begin
4924 -- Do not give warning if we are in a conditional context
4926 declare
4928 begin
4934 then
4939 -- Here warning is to be issued
4942 Error_Msg_N
4944 Error_Msg_N
4956 -- If subprogram name is a predefined operator, it was given in
4957 -- functional notation. Replace call node with operator node, so
4958 -- that actuals can be resolved appropriately.
4966 then
4972 -- Create a transient scope if the resulting type requires it
4974 -- There are 4 notable exceptions: in init procs, the transient scope
4975 -- overhead is not needed and even incorrect due to the actual expansion
4976 -- of adjust calls; the second case is enumeration literal pseudo calls;
4977 -- the third case is intrinsic subprograms (Unchecked_Conversion and
4978 -- source information functions) that do not use the secondary stack
4979 -- even though the return type is unconstrained; the fourth case is a
4980 -- call to a build-in-place function, since such functions may allocate
4981 -- their result directly in a target object, and cases where the result
4982 -- does get allocated in the secondary stack are checked for within the
4983 -- specialized Exp_Ch6 procedures for expanding build-in-place calls.
4985 -- If this is an initialization call for a type whose initialization
4986 -- uses the secondary stack, we also need to create a transient scope
4987 -- for it, precisely because we will not do it within the init proc
4988 -- itself.
4990 -- If the subprogram is marked Inline_Always, then even if it returns
4991 -- an unconstrained type the call does not require use of the secondary
4992 -- stack. However, inlining will only take place if the body to inline
4993 -- is already present. It may not be available if e.g. the subprogram is
4994 -- declared in a child instance.
5000 then
5003 elsif Expander_Active
5008 and then not Within_Init_Proc
5010 then
5013 -- If the call appears within the bounds of a loop, it will
5014 -- be rewritten and reanalyzed, nothing left to do here.
5021 and then not Within_Init_Proc
5022 then
5026 -- A protected function cannot be called within the definition of the
5027 -- enclosing protected type.
5032 then
5033 Error_Msg_NE
5037 -- Propagate interpretation to actuals, and add default expressions
5038 -- where needed.
5043 -- Overloaded literals are rewritten as function calls, for
5044 -- purpose of resolution. After resolution, we can replace
5045 -- the call with the literal itself.
5051 -- Avoid validation, since it is a static function call
5057 -- If the subprogram is not global, then kill all saved values and
5058 -- checks. This is a bit conservative, since in many cases we could do
5059 -- better, but it is not worth the effort. Similarly, we kill constant
5060 -- values. However we do not need to do this for internal entities
5061 -- (unless they are inherited user-defined subprograms), since they
5062 -- are not in the business of molesting local values.
5064 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
5065 -- kill all checks and values for calls to global subprograms. This
5066 -- takes care of the case where an access to a local subprogram is
5067 -- taken, and could be passed directly or indirectly and then called
5068 -- from almost any context.
5070 -- Note: we do not do this step till after resolving the actuals. That
5071 -- way we still take advantage of the current value information while
5072 -- scanning the actuals.
5074 -- We suppress killing values if we are processing the nodes associated
5075 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
5076 -- type kills all the values as part of analyzing the code that
5077 -- initializes the dispatch tables.
5085 then
5086 Kill_Current_Values;
5089 -- If we are warning about unread OUT parameters, this is the place to
5090 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
5091 -- after the above call to Kill_Current_Values (since that call clears
5092 -- the Last_Assignment field of all local variables).
5097 then
5098 declare
5102 begin
5113 then
5123 -- If the subprogram is a primitive operation, check whether or not
5124 -- it is a correct dispatching call.
5128 then
5133 and then not In_Instance
5134 then
5138 -- If this is a dispatching call, generate the appropriate reference,
5139 -- for better source navigation in GPS.
5143 then
5145 else
5153 -- Check for violation of restriction No_Specific_Termination_Handlers
5156 or else
5158 then
5162 -- All done, evaluate call and deal with elaboration issues
5168 -------------------------------
5169 -- Resolve_Character_Literal --
5170 -------------------------------
5176 begin
5177 -- Verify that the character does belong to the type of the context
5182 -- Wide_Wide_Character literals must always be defined, since the set
5183 -- of wide wide character literals is complete, i.e. if a character
5184 -- literal is accepted by the parser, then it is OK for wide wide
5185 -- character (out of range character literals are rejected).
5190 -- Always accept character literal for type Any_Character, which
5191 -- occurs in error situations and in comparisons of literals, both
5192 -- of which should accept all literals.
5197 -- For Standard.Character or a type derived from it, check that
5198 -- the literal is in range
5205 -- For Standard.Wide_Character or a type derived from it, check
5206 -- that the literal is in range
5213 -- For Standard.Wide_Wide_Character or a type derived from it, we
5214 -- know the literal is in range, since the parser checked!
5219 -- If the entity is already set, this has already been resolved in
5220 -- a generic context, or comes from expansion. Nothing else to do.
5225 -- Otherwise we have a user defined character type, and we can use
5226 -- the standard visibility mechanisms to locate the referenced entity
5228 else
5241 -- If we fall through, then the literal does not match any of the
5242 -- entries of the enumeration type. This isn't just a constraint
5243 -- error situation, it is an illegality (see RM 4.2).
5245 Error_Msg_NE
5249 ---------------------------
5250 -- Resolve_Comparison_Op --
5251 ---------------------------
5253 -- Context requires a boolean type, and plays no role in resolution.
5254 -- Processing identical to that for equality operators. The result
5255 -- type is the base type, which matters when pathological subtypes of
5256 -- booleans with limited ranges are used.
5263 begin
5264 -- If this is an intrinsic operation which is not predefined, use
5265 -- the types of its declared arguments to resolve the possibly
5266 -- overloaded operands. Otherwise the operands are unambiguous and
5267 -- specify the expected type.
5272 else
5287 then
5290 else
5297 else
5308 ------------------------------------
5309 -- Resolve_Conditional_Expression --
5310 ------------------------------------
5317 begin
5326 -----------------------------------------
5327 -- Resolve_Discrete_Subtype_Indication --
5328 -----------------------------------------
5330 procedure Resolve_Discrete_Subtype_Indication
5333 is
5337 begin
5345 else
5355 Error_Msg_NE
5358 -- Rewrite the constraint as a range of Typ
5359 -- to allow compilation to proceed further.
5371 else
5375 -- Additionally, we must check that the bounds are compatible
5376 -- with the given subtype, which might be different from the
5377 -- type of the context.
5381 -- ??? If the above check statically detects a Constraint_Error
5382 -- it replaces the offending bound(s) of the range R with a
5383 -- Constraint_Error node. When the itype which uses these bounds
5384 -- is frozen the resulting call to Duplicate_Subexpr generates
5385 -- a new temporary for the bounds.
5387 -- Unfortunately there are other itypes that are also made depend
5388 -- on these bounds, so when Duplicate_Subexpr is called they get
5389 -- a forward reference to the newly created temporaries and Gigi
5390 -- aborts on such forward references. This is probably sign of a
5391 -- more fundamental problem somewhere else in either the order of
5392 -- itype freezing or the way certain itypes are constructed.
5394 -- To get around this problem we call Remove_Side_Effects right
5395 -- away if either bounds of R are a Constraint_Error.
5397 declare
5401 begin
5417 -------------------------
5418 -- Resolve_Entity_Name --
5419 -------------------------
5421 -- Used to resolve identifiers and expanded names
5426 begin
5427 -- If garbage from errors, set to Any_Type and return
5434 -- Replace named numbers by corresponding literals. Note that this is
5435 -- the one case where Resolve_Entity_Name must reset the Etype, since
5436 -- it is currently marked as universal.
5446 -- Allow use of subtype only if it is a concurrent type where we are
5447 -- currently inside the body. This will eventually be expanded
5448 -- into a call to Self (for tasks) or _object (for protected
5449 -- objects). Any other use of a subtype is invalid.
5454 then
5456 else
5457 Error_Msg_N
5461 -- Check discriminant use if entity is discriminant in current scope,
5462 -- i.e. discriminant of record or concurrent type currently being
5463 -- analyzed. Uses in corresponding body are unrestricted.
5468 then
5471 -- A parameterless generic function cannot appear in a context that
5472 -- requires resolution.
5483 then
5486 -- In all other cases, just do the possible static evaluation
5488 else
5489 -- A deferred constant that appears in an expression must have
5490 -- a completion, unless it has been removed by in-place expansion
5491 -- of an aggregate.
5497 and then not In_Spec_Expression
5499 then
5504 then
5506 else
5507 Error_Msg_N (
5516 -------------------
5517 -- Resolve_Entry --
5518 -------------------
5530 -- If the bounds of the entry family being called depend on task
5531 -- discriminants, build a new index subtype where a discriminant is
5532 -- replaced with the value of the discriminant of the target task.
5533 -- The target task is the prefix of the entry name in the call.
5535 -----------------------
5536 -- Actual_Index_Type --
5537 -----------------------
5547 -- If the bound is given by a discriminant, replace with a reference
5548 -- to the discriminant of the same name in the target task.
5549 -- If the entry name is the target of a requeue statement and the
5550 -- entry is in the current protected object, the bound to be used
5551 -- is the discriminal of the object (see apply_range_checks for
5552 -- details of the transformation).
5554 -----------------------------
5555 -- Actual_Discriminant_Ref --
5556 -----------------------------
5562 begin
5567 then
5573 then
5576 else
5577 Ref :=
5587 -- Start of processing for Actual_Index_Type
5589 begin
5593 then
5596 else
5610 -- Start of processing of Resolve_Entry
5612 begin
5613 -- Find name of entry being called, and resolve prefix of name
5614 -- with its own type. The prefix can be overloaded, and the name
5615 -- and signature of the entry must be taken into account.
5619 -- Case of dealing with entry family within the current tasks
5623 else
5628 -- Entry call to an entry (or entry family) in the current task.
5629 -- This is legal even though the task will deadlock. Rewrite as
5630 -- call to current task.
5632 -- This can also be a call to an entry in an enclosing task.
5633 -- If this is a single task, we have to retrieve its name,
5634 -- because the scope of the entry is the task type, not the
5635 -- object. If the enclosing task is a task type, the identity
5636 -- of the task is given by its own self variable.
5638 -- Finally this can be a requeue on an entry of the same task
5639 -- or protected object.
5647 then
5648 -- S is an enclosing task or protected object. The concurrent
5649 -- declaration has been converted into a type declaration, and
5650 -- the object itself has an object declaration that follows
5651 -- the type in the same declarative part.
5663 -- Call to current task. Will be transformed into call to Self
5670 New_N :=
5673 Selector_Name =>
5680 then
5681 -- Use the entry name (which must be unique at this point) to
5682 -- find the prefix that returns the corresponding task type or
5683 -- protected type.
5685 declare
5691 begin
5713 -- Up to this point the expression could have been the actual
5714 -- in a simple entry call, and be given by a named association.
5718 else
5724 ------------------------
5725 -- Resolve_Entry_Call --
5726 ------------------------
5738 begin
5739 -- We kill all checks here, because it does not seem worth the
5740 -- effort to do anything better, an entry call is a big operation.
5742 Kill_All_Checks;
5744 -- Processing of the name is similar for entry calls and protected
5745 -- operation calls. Once the entity is determined, we can complete
5746 -- the resolution of the actuals.
5748 -- The selector may be overloaded, in the case of a protected object
5749 -- with overloaded functions. The type of the context is used for
5750 -- resolution.
5755 then
5756 declare
5760 begin
5779 -- Simple entry call
5787 -- Call to member of entry family
5794 -- We cannot in general check the maximum depth of protected entry
5795 -- calls at compile time. But we can tell that any protected entry
5796 -- call at all violates a specified nesting depth of zero.
5802 -- Use context type to disambiguate a protected function that can be
5803 -- called without actuals and that returns an array type, and where
5804 -- the argument list may be an indexing of the returned value.
5809 and then
5817 then
5818 declare
5821 begin
5822 Index_Node :=
5824 Prefix =>
5829 -- Since we are correcting a node classification error made by
5830 -- the parser, we call Replace rather than Rewrite.
5840 -- The operation name may have been overloaded. Order the actuals
5841 -- according to the formals of the resolved entity, and set the
5842 -- return type to that of the operation.
5855 then
5859 -- Verify that a procedure call cannot masquerade as an entry
5860 -- call where an entry call is expected.
5865 then
5870 then
5875 then
5880 -- After resolution, entry calls and protected procedure calls
5881 -- are changed into entry calls, for expansion. The structure
5882 -- of the node does not change, so it can safely be done in place.
5883 -- Protected function calls must keep their structure because they
5884 -- are subexpressions.
5888 -- A protected operation that is not a function may modify the
5889 -- corresponding object, and cannot apply to a constant.
5890 -- If this is an internal call, the prefix is the type itself.
5896 then
5897 Error_Msg_N
5899 Entry_Name);
5913 -- Protected functions can return on the secondary stack, in which
5914 -- case we must trigger the transient scope mechanism.
5916 elsif Expander_Active
5918 then
5923 -------------------------
5924 -- Resolve_Equality_Op --
5925 -------------------------
5927 -- Both arguments must have the same type, and the boolean context
5928 -- does not participate in the resolution. The first pass verifies
5929 -- that the interpretation is not ambiguous, and the type of the left
5930 -- argument is correctly set, or is Any_Type in case of ambiguity.
5931 -- If both arguments are strings or aggregates, allocators, or Null,
5932 -- they are ambiguous even though they carry a single (universal) type.
5933 -- Diagnose this case here.
5941 -- In the case of allocators, make a last-ditch attempt to find a single
5942 -- access type with the right designated type. This is semantically
5943 -- dubious, and of no interest to any real code, but c48008a makes it
5944 -- all worthwhile.
5946 -----------------------------
5947 -- Find_Unique_Access_Type --
5948 -----------------------------
5955 begin
5960 else
5972 then
5985 -- Start of processing for Resolve_Equality_Op
5987 begin
5999 then
6002 else
6012 then
6025 -- If the unique type is a class-wide type then it will be expanded
6026 -- into a dispatching call to the predefined primitive. Therefore we
6027 -- check here for potential violation of such restriction.
6033 if Warn_On_Redundant_Constructs
6038 then
6046 -- If this is an inequality, it may be the implicit inequality
6047 -- created for a user-defined operation, in which case the corres-
6048 -- ponding equality operation is not intrinsic, and the operation
6049 -- cannot be constant-folded. Else fold.
6054 or else Is_Intrinsic_Subprogram
6056 then
6061 then
6065 -- Ada 2005: If one operand is an anonymous access type, convert
6066 -- the other operand to it, to ensure that the underlying types
6067 -- match in the back-end. Same for access_to_subprogram, and the
6068 -- conversion verifies that the types are subtype conformant.
6070 -- We apply the same conversion in the case one of the operands is
6071 -- a private subtype of the type of the other.
6073 -- Why the Expander_Active test here ???
6075 if Expander_Active
6076 and then
6080 then
6100 ----------------------------------
6101 -- Resolve_Explicit_Dereference --
6102 ----------------------------------
6111 begin
6116 -- Use the context type to select the prefix that has the correct
6117 -- designated type.
6128 else
6129 -- If no interpretation covers the designated type of the prefix,
6130 -- this is the pathological case where not all implementations of
6131 -- the prefix allow the interpretation of the node as a call. Now
6132 -- that the expected type is known, Remove other interpretations
6133 -- from prefix, rewrite it as a call, and resolve again, so that
6134 -- the proper call node is generated.
6145 New_N :=
6147 Name =>
6160 else
6168 -- If the designated type is a packed unconstrained array type, and the
6169 -- explicit dereference is not in the context of an attribute reference,
6170 -- then we must compute and set the actual subtype, since it is needed
6171 -- by Gigi. The reason we exclude the attribute case is that this is
6172 -- handled fine by Gigi, and in fact we use such attributes to build the
6173 -- actual subtype. We also exclude generated code (which builds actual
6174 -- subtypes directly if they are needed).
6181 then
6185 -- Note: there is no Eval processing required for an explicit deference,
6186 -- because the type is known to be an allocators, and allocator
6187 -- expressions can never be static.
6191 -------------------------------
6192 -- Resolve_Indexed_Component --
6193 -------------------------------
6201 begin
6204 -- Use the context type to select the prefix that yields the correct
6205 -- component type.
6207 declare
6214 begin
6221 and then Covers
6223 then
6232 else
6238 else
6249 else
6256 -- If prefix is access type, dereference to get real array type.
6257 -- Note: we do not apply an access check because the expander always
6258 -- introduces an explicit dereference, and the check will happen there.
6264 -- If name was overloaded, set component type correctly now
6265 -- If a misplaced call to an entry family (which has no index types)
6266 -- return. Error will be diagnosed from calling context.
6270 else
6277 -- The prefix may have resolved to a string literal, in which case its
6278 -- etype has a special representation. This is only possible currently
6279 -- if the prefix is a static concatenation, written in functional
6280 -- notation.
6285 else
6292 else
6301 -- Do not generate the warning on suspicious index if we are analyzing
6302 -- package Ada.Tags; otherwise we will report the warning with the
6303 -- Prims_Ptr field of the dispatch table.
6306 or else not
6308 Ada_Tags)
6309 then
6315 -----------------------------
6316 -- Resolve_Integer_Literal --
6317 -----------------------------
6320 begin
6325 --------------------------------
6326 -- Resolve_Intrinsic_Operator --
6327 --------------------------------
6335 begin
6345 -- If the operand type is private, rewrite with suitable conversions on
6346 -- the operands and the result, to expose the proper underlying numeric
6347 -- type.
6354 else
6370 then
6371 -- Add explicit conversion where needed, and save interpretations
6372 -- in case operands are overloaded.
6379 else
6385 else
6395 else
6400 --------------------------------------
6401 -- Resolve_Intrinsic_Unary_Operator --
6402 --------------------------------------
6404 procedure Resolve_Intrinsic_Unary_Operator
6407 is
6412 begin
6431 else
6436 ------------------------
6437 -- Resolve_Logical_Op --
6438 ------------------------
6444 begin
6445 -- Predefined operations on scalar types yield the base type. On the
6446 -- other hand, logical operations on arrays yield the type of the
6447 -- arguments (and the context).
6451 else
6455 -- The following test is required because the operands of the operation
6456 -- may be literals, in which case the resulting type appears to be
6457 -- compatible with a signed integer type, when in fact it is compatible
6458 -- only with modular types. If the context itself is universal, the
6459 -- operation is illegal.
6467 Error_Msg_N
6474 then
6488 -- Check for violation of restriction No_Direct_Boolean_Operators
6489 -- if the operator was not eliminated by the Eval_Logical_Op call.
6493 then
6498 ---------------------------
6499 -- Resolve_Membership_Op --
6500 ---------------------------
6502 -- The context can only be a boolean type, and does not determine
6503 -- the arguments. Arguments should be unambiguous, but the preference
6504 -- rule for universal types applies.
6513 begin
6519 and then
6523 then
6526 -- Ada 2005 (AI-251): Give support to the following case:
6528 -- type I is interface;
6529 -- type T is tagged ...
6531 -- function Test (O : I'Class) is
6532 -- begin
6533 -- return O in T'Class.
6534 -- end Test;
6536 -- In this case we have nothing else to do; the membership test will be
6537 -- done at run-time.
6544 then
6547 else
6556 then
6562 else
6570 ------------------
6571 -- Resolve_Null --
6572 ------------------
6575 begin
6576 -- Handle restriction against anonymous null access values This
6577 -- restriction can be turned off using -gnatdj.
6579 -- Ada 2005 (AI-231): Remove restriction
6582 and then not Debug_Flag_J
6585 then
6586 -- In the common case of a call which uses an explicitly null
6587 -- value for an access parameter, give specialized error message.
6590 N_Function_Call)
6591 then
6592 Error_Msg_N
6595 -- Standard message for all other cases (are there any?)
6597 else
6598 Error_Msg_N
6603 -- In a distributed context, null for a remote access to subprogram
6604 -- may need to be replaced with a special record aggregate. In this
6605 -- case, return after having done the transformation.
6610 then
6614 -- The null literal takes its type from the context
6619 -----------------------
6620 -- Resolve_Op_Concat --
6621 -----------------------
6625 -- We wish to avoid deep recursion, because concatenations are often
6626 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
6627 -- operands nonrecursively until we find something that is not a simple
6628 -- concatenation (A in this case). We resolve that, and then walk back
6629 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
6630 -- to do the rest of the work at each level. The Parent pointers allow
6631 -- us to avoid recursion, and thus avoid running out of memory. See also
6632 -- Sem_Ch4.Analyze_Concatenation, where a similar hack is used.
6637 begin
6638 -- The following code is equivalent to:
6640 -- Resolve_Op_Concat_First (NN, Typ);
6641 -- Resolve_Op_Concat_Arg (N, ...);
6642 -- Resolve_Op_Concat_Rest (N, Typ);
6644 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
6645 -- operand is a concatenation.
6647 -- Walk down left operands
6649 loop
6658 -- Now (given the above example) NN is A&B and Op1 is A
6660 -- First resolve Op1 ...
6664 -- ... then walk NN back up until we reach N (where we started), calling
6665 -- Resolve_Op_Concat_Rest along the way.
6667 loop
6674 ---------------------------
6675 -- Resolve_Op_Concat_Arg --
6676 ---------------------------
6678 procedure Resolve_Op_Concat_Arg
6683 is
6686 begin
6688 if Is_Comp
6692 then
6694 else
6701 then
6704 else
6709 else
6713 then
6714 declare
6719 begin
6724 -- Special-case the error message when the overloading is
6725 -- caused by a function that yields an array and can be
6726 -- called without parameters.
6731 Error_Msg_NE
6733 Error_Msg_NE
6737 else
6738 Error_Msg_N
6747 then
6765 else
6770 else
6777 -----------------------------
6778 -- Resolve_Op_Concat_First --
6779 -----------------------------
6786 begin
6787 -- The parser folds an enormous sequence of concatenations of string
6788 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
6789 -- in the right. If the expression resolves to a predefined "&"
6790 -- operator, all is well. Otherwise, the parser's folding is wrong, so
6791 -- we give an error. See P_Simple_Expression in Par.Ch4.
6796 then
6811 ----------------------------
6812 -- Resolve_Op_Concat_Rest --
6813 ----------------------------
6819 begin
6828 -- If this is not a static concatenation, but the result is a
6829 -- string type (and not an array of strings) ensure that static
6830 -- string operands have their subtypes properly constructed.
6834 then
6840 ----------------------
6841 -- Resolve_Op_Expon --
6842 ----------------------
6847 begin
6848 -- Catch attempts to do fixed-point exponentiation with universal
6849 -- operands, which is a case where the illegality is not caught during
6850 -- normal operator analysis.
6861 then
6868 then
6872 -- We do the resolution using the base type, because intermediate values
6873 -- in expressions always are of the base type, not a subtype of it.
6885 -- Set overflow checking bit. Much cleverer code needed here eventually
6886 -- and perhaps the Resolve routines should be separated for the various
6887 -- arithmetic operations, since they will need different processing. ???
6896 --------------------
6897 -- Resolve_Op_Not --
6898 --------------------
6904 -- This function determines if the parent node is a boolean operator
6905 -- or operation (comparison op, membership test, or short circuit form)
6906 -- and the not in question is the left operand of this operation.
6907 -- Note that if the not is in parens, then false is returned.
6909 -----------------------
6910 -- Parent_Is_Boolean --
6911 -----------------------
6914 begin
6918 else
6920 when N_Op_And |
6921 N_Op_Eq |
6922 N_Op_Ge |
6923 N_Op_Gt |
6924 N_Op_Le |
6925 N_Op_Lt |
6926 N_Op_Ne |
6927 N_Op_Or |
6928 N_Op_Xor |
6929 N_In |
6930 N_Not_In |
6931 N_And_Then |
6932 N_Or_Else =>
6942 -- Start of processing for Resolve_Op_Not
6944 begin
6945 -- Predefined operations on scalar types yield the base type. On the
6946 -- other hand, logical operations on arrays yield the type of the
6947 -- arguments (and the context).
6951 else
6955 -- Straightforward case of incorrect arguments
6962 -- Special case of probable missing parens
6966 Error_Msg_N
6969 else
6970 Error_Msg_N
6977 -- OK resolution of not
6979 else
6980 -- Warn if non-boolean types involved. This is a case like not a < b
6981 -- where a and b are modular, where we will get (not a) < b and most
6982 -- likely not (a < b) was intended.
6984 if Warn_On_Questionable_Missing_Parens
6986 and then Parent_Is_Boolean
6987 then
6991 -- Warn on double negation if checking redundant constructs
6993 if Warn_On_Redundant_Constructs
6998 then
7002 -- Complete resolution and evaluation of NOT
7012 -----------------------------
7013 -- Resolve_Operator_Symbol --
7014 -----------------------------
7016 -- Nothing to be done, all resolved already
7022 begin
7026 ----------------------------------
7027 -- Resolve_Qualified_Expression --
7028 ----------------------------------
7036 begin
7039 -- A qualified expression requires an exact match of the type,
7040 -- class-wide matching is not allowed. However, if the qualifying
7041 -- type is specific and the expression has a class-wide type, it
7042 -- may still be okay, since it can be the result of the expansion
7043 -- of a call to a dispatching function, so we also have to check
7044 -- class-wideness of the type of the expression's original node.
7047 or else
7051 then
7055 -- If the target type is unconstrained, then we reset the type of
7056 -- the result from the type of the expression. For other cases, the
7057 -- actual subtype of the expression is the target type.
7061 then
7068 -------------------
7069 -- Resolve_Range --
7070 -------------------
7076 begin
7084 -- We have to check the bounds for being within the base range as
7085 -- required for a non-static context. Normally this is automatic and
7086 -- done as part of evaluating expressions, but the N_Range node is an
7087 -- exception, since in GNAT we consider this node to be a subexpression,
7088 -- even though in Ada it is not. The circuit in Sem_Eval could check for
7089 -- this, but that would put the test on the main evaluation path for
7090 -- expressions.
7095 -- Check for an ambiguous range over character literals. This will
7096 -- happen with a membership test involving only literals.
7104 -- If bounds are static, constant-fold them, so size computations
7105 -- are identical between front-end and back-end. Do not perform this
7106 -- transformation while analyzing generic units, as type information
7107 -- would then be lost when reanalyzing the constant node in the
7108 -- instance.
7121 --------------------------
7122 -- Resolve_Real_Literal --
7123 --------------------------
7128 begin
7129 -- Special processing for fixed-point literals to make sure that the
7130 -- value is an exact multiple of small where this is required. We
7131 -- skip this for the universal real case, and also for generic types.
7137 then
7138 declare
7145 begin
7146 -- Case of literal is not an exact multiple of the Small
7150 -- For a source program literal for a decimal fixed-point
7151 -- type, this is statically illegal (RM 4.9(36)).
7156 then
7160 -- Generate a warning if literal from source
7163 and then Warn_On_Bad_Fixed_Value
7164 then
7165 Error_Msg_N
7167 N);
7170 -- Replace literal by a value that is the exact representation
7171 -- of a value of the type, i.e. a multiple of the small value,
7172 -- by truncation, since Machine_Rounds is false for all GNAT
7173 -- fixed-point types (RM 4.9(38)).
7183 -- In all cases, set the corresponding integer field
7189 -- Now replace the actual type by the expected type as usual
7195 -----------------------
7196 -- Resolve_Reference --
7197 -----------------------
7202 begin
7203 -- Replace general access with specific type
7211 -- If we are taking the reference of a volatile entity, then treat
7212 -- it as a potential modification of this entity. This is much too
7213 -- conservative, but is necessary because remove side effects can
7214 -- result in transformations of normal assignments into reference
7215 -- sequences that otherwise fail to notice the modification.
7222 --------------------------------
7223 -- Resolve_Selected_Component --
7224 --------------------------------
7239 -- Check whether this is the initialization of a component within an
7240 -- init proc (by assignment or call to another init proc). If true,
7241 -- there is no need for a discriminant check.
7243 --------------------
7244 -- Init_Component --
7245 --------------------
7248 begin
7249 return Inside_Init_Proc
7255 -- Start of processing for Resolve_Selected_Component
7257 begin
7260 -- Use the context type to select the prefix that has a selector
7261 -- of the correct name and type.
7269 else
7275 -- The visible components of a class-wide type are those of
7276 -- the root type.
7286 then
7293 else
7297 Error_Msg_N
7302 else
7305 -- There may be an implicit dereference. Retrieve
7306 -- designated record type.
7310 else
7316 -- Resolution chooses the new interpretation.
7317 -- Find the component with the right name.
7322 loop
7344 else
7345 -- Resolve prefix with its type
7350 -- Generate cross-reference. We needed to wait until full overloading
7351 -- resolution was complete to do this, since otherwise we can't tell if
7352 -- we are an Lvalue of not.
7356 else
7360 -- If prefix is an access type, the node will be transformed into an
7361 -- explicit dereference during expansion. The type of the node is the
7362 -- designated type of that of the prefix.
7367 else
7373 or else
7380 and then not Init_Component
7381 then
7389 -- If the prefix is a record conversion, this may be a renamed
7390 -- discriminant whose bounds differ from those of the original
7391 -- one, so we must ensure that a range check is performed.
7396 then
7400 -- Note: No Eval processing is required, because the prefix is of a
7401 -- record type, or protected type, and neither can possibly be static.
7405 -------------------
7406 -- Resolve_Shift --
7407 -------------------
7414 begin
7415 -- We do the resolution using the base type, because intermediate values
7416 -- in expressions always are of the base type, not a subtype of it.
7429 ---------------------------
7430 -- Resolve_Short_Circuit --
7431 ---------------------------
7438 begin
7442 -- Check for issuing warning for always False assert/check, this happens
7443 -- when assertions are turned off, in which case the pragma Assert/Check
7444 -- was transformed into:
7446 -- if False and then <condition> then ...
7448 -- and we detect this pattern
7450 if Warn_On_Assertion_Failure
7457 then
7458 declare
7461 begin
7464 then
7465 -- Don't want to warn if original condition is explicit False
7467 declare
7469 Original_Node
7470 (Expression
7472 begin
7475 then
7477 else
7478 -- Issue warning. Note that we don't want to make this
7479 -- an unconditional warning, because if the assert is
7480 -- within deleted code we do not want the warning. But
7481 -- we do not want the deletion of the IF/AND-THEN to
7482 -- take this message with it. We achieve this by making
7483 -- sure that the expanded code points to the Sloc of
7484 -- the expression, not the original pragma.
7490 -- Similar processing for Check pragma
7494 then
7495 -- Don't want to warn if original condition is explicit False
7497 declare
7499 Original_Node
7500 (Expression
7503 begin
7506 then
7508 else
7516 -- Continue with processing of short circuit
7525 -------------------
7526 -- Resolve_Slice --
7527 -------------------
7535 begin
7538 -- Use the context type to select the prefix that yields the
7539 -- correct array type.
7541 declare
7548 begin
7556 then
7564 else
7569 else
7580 else
7590 -- If the prefix is an access to an unconstrained array, we must use
7591 -- the actual subtype of the object to perform the index checks. The
7592 -- object denoted by the prefix is implicit in the node, so we build
7593 -- an explicit representation for it in order to compute the actual
7594 -- subtype.
7599 declare
7603 begin
7613 then
7616 -- If the name is a selected component that depends on discriminants,
7617 -- build an actual subtype for it. This can happen only when the name
7618 -- itself is overloaded; otherwise the actual subtype is created when
7619 -- the selected component is analyzed.
7622 and then Full_Analysis
7624 then
7625 declare
7628 begin
7634 -- If name was overloaded, set slice type correctly now
7638 -- If the range is specified by a subtype mark, no resolution is
7639 -- necessary. Else resolve the bounds, and apply needed checks.
7647 -- Do not apply the range check to nodes associated with the
7648 -- frontend expansion of the dispatch table. We first check
7649 -- if Ada.Tags is already loaded to void the addition of an
7650 -- undesired dependence on such run-time unit.
7652 and then
7654 or else not
7660 then
7675 ----------------------------
7676 -- Resolve_String_Literal --
7677 ----------------------------
7688 begin
7689 -- For a string appearing in a concatenation, defer creation of the
7690 -- string_literal_subtype until the end of the resolution of the
7691 -- concatenation, because the literal may be constant-folded away. This
7692 -- is a useful optimization for long concatenation expressions.
7694 -- If the string is an aggregate built for a single character (which
7695 -- happens in a non-static context) or a is null string to which special
7696 -- checks may apply, we build the subtype. Wide strings must also get a
7697 -- string subtype if they come from a one character aggregate. Strings
7698 -- generated by attributes might be static, but it is often hard to
7699 -- determine whether the enclosing context is static, so we generate
7700 -- subtypes for them as well, thus losing some rarer optimizations ???
7701 -- Same for strings that come from a static conversion.
7703 Need_Check :=
7712 -- If the resolving type is itself a string literal subtype, we
7713 -- can just reuse it, since there is no point in creating another.
7719 and then not Need_Check
7721 N_Attribute_Reference,
7722 N_Qualified_Expression,
7723 N_Type_Conversion)
7724 then
7727 -- Otherwise we must create a string literal subtype. Note that the
7728 -- whole idea of string literal subtypes is simply to avoid the need
7729 -- for building a full fledged array subtype for each literal.
7731 else
7737 or else Need_Check
7738 then
7745 then
7751 -- The validity of a null string has been checked in the
7752 -- call to Eval_String_Literal.
7757 -- Always accept string literal with component type Any_Character, which
7758 -- occurs in error situations and in comparisons of literals, both of
7759 -- which should accept all literals.
7764 -- If the type is bit-packed, then we always transform the string
7765 -- literal into a full fledged aggregate.
7770 -- Deal with cases of Wide_Wide_String, Wide_String, and String
7772 else
7773 -- For Standard.Wide_Wide_String, or any other type whose component
7774 -- type is Standard.Wide_Wide_Character, we know that all the
7775 -- characters in the string must be acceptable, since the parser
7776 -- accepted the characters as valid character literals.
7781 -- For the case of Standard.String, or any other type whose component
7782 -- type is Standard.Character, we must make sure that there are no
7783 -- wide characters in the string, i.e. that it is entirely composed
7784 -- of characters in range of type Character.
7786 -- If the string literal is the result of a static concatenation, the
7787 -- test has already been performed on the components, and need not be
7788 -- repeated.
7792 then
7796 -- If we are out of range, post error. This is one of the
7797 -- very few places that we place the flag in the middle of
7798 -- a token, right under the offending wide character.
7800 Error_Msg
7807 -- For the case of Standard.Wide_String, or any other type whose
7808 -- component type is Standard.Wide_Character, we must make sure that
7809 -- there are no wide characters in the string, i.e. that it is
7810 -- entirely composed of characters in range of type Wide_Character.
7812 -- If the string literal is the result of a static concatenation,
7813 -- the test has already been performed on the components, and need
7814 -- not be repeated.
7818 then
7822 -- If we are out of range, post error. This is one of the
7823 -- very few places that we place the flag in the middle of
7824 -- a token, right under the offending wide character.
7826 -- This is not quite right, because characters in general
7827 -- will take more than one character position ???
7829 Error_Msg
7836 -- If the root type is not a standard character, then we will convert
7837 -- the string into an aggregate and will let the aggregate code do
7838 -- the checking. Standard Wide_Wide_Character is also OK here.
7840 else
7844 -- See if the component type of the array corresponding to the string
7845 -- has compile time known bounds. If yes we can directly check
7846 -- whether the evaluation of the string will raise constraint error.
7847 -- Otherwise we need to transform the string literal into the
7848 -- corresponding character aggregate and let the aggregate
7849 -- code do the checking.
7853 -- Check for the case of full range, where we are definitely OK
7859 -- Here the range is not the complete base type range, so check
7861 declare
7869 begin
7872 then
7878 then
7879 Apply_Compile_Time_Constraint_Error
7891 -- If we got here we meed to transform the string literal into the
7892 -- equivalent qualified positional array aggregate. This is rather
7893 -- heavy artillery for this situation, but it is hard work to avoid.
7895 declare
7900 begin
7901 -- Build the character literals, we give them source locations that
7902 -- correspond to the string positions, which is a bit tricky given
7903 -- the possible presence of wide character escape sequences.
7917 -- Should we have a call to Skip_Wide here ???
7918 -- ??? else
7919 -- Skip_Wide (P);
7927 Expression =>
7934 -----------------------------
7935 -- Resolve_Subprogram_Info --
7936 -----------------------------
7939 begin
7943 -----------------------------
7944 -- Resolve_Type_Conversion --
7945 -----------------------------
7956 begin
7957 if not Conv_OK
7959 then
7965 -- Mixed-mode operation involving a literal. Context must be a fixed
7966 -- type which is applied to the literal subsequently.
7974 or else
7976 then
7977 -- Return if expression is ambiguous
7982 -- If nothing else, the available fixed type is Duration
7984 else
7988 -- Resolve the real operand with largest available precision
7992 else
7998 -- If the operand is a literal (it could be a non-static and
7999 -- illegal exponentiation) check whether the use of Duration
8000 -- is potentially inaccurate.
8005 then
8006 Error_Msg_N
8009 Rop);
8010 Error_Msg_N
8017 then
8020 else
8029 -- Note: we do the Eval_Type_Conversion call before applying the
8030 -- required checks for a subtype conversion. This is important,
8031 -- since both are prepared under certain circumstances to change
8032 -- the type conversion to a constraint error node, but in the case
8033 -- of Eval_Type_Conversion this may reflect an illegality in the
8034 -- static case, and we would miss the illegality (getting only a
8035 -- warning message), if we applied the type conversion checks first.
8039 -- Even when evaluation is not possible, we may be able to simplify
8040 -- the conversion or its expression. This needs to be done before
8041 -- applying checks, since otherwise the checks may use the original
8042 -- expression and defeat the simplifications. This is specifically
8043 -- the case for elimination of the floating-point Truncation
8044 -- attribute in float-to-int conversions.
8048 -- If after evaluation we still have a type conversion, then we
8049 -- may need to apply checks required for a subtype conversion.
8051 -- Skip these type conversion checks if universal fixed operands
8052 -- operands involved, since range checks are handled separately for
8053 -- these cases (in the appropriate Expand routines in unit Exp_Fixd).
8059 then
8063 -- Issue warning for conversion of simple object to its own type
8064 -- We have to test the original nodes, since they may have been
8065 -- rewritten by various optimizations.
8069 if Warn_On_Redundant_Constructs
8072 and then not In_Instance
8073 then
8077 -- If the node is part of a larger expression, the Target_Type
8078 -- may not be the original type of the node if the context is a
8079 -- condition. Recover original type to see if conversion is needed.
8083 then
8088 and then
8090 or else
8093 then
8095 Error_Msg_NE
8100 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
8101 -- No need to perform any interface conversion if the type of the
8102 -- expression coincides with the target type.
8105 and then Expander_Active
8107 then
8108 declare
8112 begin
8124 -- Conversion from interface type
8128 -- Ada 2005 (AI-217): Handle entities from limited views
8134 Error_Msg_N
8136 N);
8139 and then not
8142 then
8146 Error_Msg_N
8148 N);
8150 else
8154 -- Conversion to interface type
8158 -- Handle subtypes
8162 then
8166 if not Interface_Present_In_Ancestor
8169 then
8172 -- The static analysis is not enough to know if the
8173 -- interface is implemented or not. Hence we must pass
8174 -- the work to the expander to generate code to evaluate
8175 -- the conversion at run-time.
8179 else
8182 Error_Msg_N
8187 else
8195 ----------------------
8196 -- Resolve_Unary_Op --
8197 ----------------------
8206 begin
8207 -- Deal with intrinsic unary operators
8213 then
8218 -- Deal with universal cases
8221 or else
8223 then
8230 -- Generate warning for expressions like abs (x mod 2)
8232 if Warn_On_Redundant_Constructs
8234 then
8238 Error_Msg_N
8243 -- Deal with reference generation
8249 -- Set overflow checking bit. Much cleverer code needed here eventually
8250 -- and perhaps the Resolve routines should be separated for the various
8251 -- arithmetic operations, since they will need different processing ???
8259 -- Generate warning for expressions like -5 mod 3 for integers. No
8260 -- need to worry in the floating-point case, since parens do not affect
8261 -- the result so there is no point in giving in a warning.
8263 declare
8272 begin
8273 if Warn_On_Questionable_Missing_Parens
8277 then
8280 -- We are looking for cases where the right operand is not
8281 -- parenthesized, and is a binary operator, multiply, divide, or
8282 -- mod. These are the cases where the grouping can affect results.
8286 then
8287 -- For mod, we always give the warning, since the value is
8288 -- affected by the parenthesization (e.g. (-5) mod 315 /=
8289 -- (5 mod 315)). But for the other cases, the only concern is
8290 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
8291 -- overflows, but (-2) * 64 does not). So we try to give the
8292 -- message only when overflow is possible.
8296 then
8301 else
8307 else
8311 -- Note that the test below is deliberately excluding
8312 -- the largest negative number, since that is a potentially
8313 -- troublesome case (e.g. -2 * x, where the result is the
8314 -- largest negative integer has an overflow with 2 * x).
8321 -- For the multiplication case, the only case we have to worry
8322 -- about is when (-a)*b is exactly the largest negative number
8323 -- so that -(a*b) can cause overflow. This can only happen if
8324 -- a is a power of 2, and more generally if any operand is a
8325 -- constant that is not a power of 2, then the parentheses
8326 -- cannot affect whether overflow occurs. We only bother to
8327 -- test the left most operand
8329 -- Loop looking at left operands for one that has known value
8336 -- Operand value of 0 or 1 skips warning
8341 -- Otherwise check power of 2, if power of 2, warn, if
8342 -- anything else, skip warning.
8344 else
8348 else
8357 -- Keep looking at left operands
8362 -- For rem or "/" we can only have a problematic situation
8363 -- if the divisor has a value of minus one or one. Otherwise
8364 -- overflow is impossible (divisor > 1) or we have a case of
8365 -- division by zero in any case.
8370 then
8374 -- If we fall through warning should be issued
8376 Error_Msg_N
8383 ----------------------------------
8384 -- Resolve_Unchecked_Expression --
8385 ----------------------------------
8387 procedure Resolve_Unchecked_Expression
8390 is
8391 begin
8396 ---------------------------------------
8397 -- Resolve_Unchecked_Type_Conversion --
8398 ---------------------------------------
8400 procedure Resolve_Unchecked_Type_Conversion
8403 is
8409 begin
8410 -- Resolve operand using its own type
8417 ------------------------------
8418 -- Rewrite_Operator_As_Call --
8419 ------------------------------
8426 begin
8433 New_N :=
8444 ------------------------------
8445 -- Rewrite_Renamed_Operator --
8446 ------------------------------
8448 procedure Rewrite_Renamed_Operator
8452 is
8457 begin
8458 -- Rewrite the operator node using the real operator, not its
8459 -- renaming. Exclude user-defined intrinsic operations of the same
8460 -- name, which are treated separately and rewritten as calls.
8464 then
8471 -- Indicate that both the original entity and its renaming are
8472 -- referenced at this point.
8483 -- If the context type is private, add the appropriate conversions
8484 -- so that the operator is applied to the full view. This is done
8485 -- in the routines that resolve intrinsic operators,
8489 then
8491 when N_Op_Add | N_Op_Subtract | N_Op_Multiply | N_Op_Divide |
8492 N_Op_Expon | N_Op_Mod | N_Op_Rem =>
8505 then
8506 -- Operator renames a user-defined operator of the same name. Use
8507 -- the original operator in the node, which is the one that Gigi
8508 -- knows about.
8515 -----------------------
8516 -- Set_Slice_Subtype --
8517 -----------------------
8519 -- Build an implicit subtype declaration to represent the type delivered
8520 -- by the slice. This is an abbreviated version of an array subtype. We
8521 -- define an index subtype for the slice, using either the subtype name
8522 -- or the discrete range of the slice. To be consistent with index usage
8523 -- elsewhere, we create a list header to hold the single index. This list
8524 -- is not otherwise attached to the syntax tree.
8535 begin
8539 else
8540 -- We force the evaluation of a range. This is definitely needed in
8541 -- the renamed case, and seems safer to do unconditionally. Note in
8542 -- any case that since we will create and insert an Itype referring
8543 -- to this range, we must make sure any side effect removal actions
8544 -- are inserted before the Itype definition.
8573 -- The Etype of the existing Slice node is reset to this slice subtype.
8574 -- Its bounds are obtained from its first index.
8578 -- In the packed case, this must be immediately frozen
8580 -- Couldn't we always freeze here??? and if we did, then the above
8581 -- call to Check_Compile_Time_Size could be eliminated, which would
8582 -- be nice, because then that routine could be made private to Freeze.
8584 -- Why the test for In_Spec_Expression here ???
8592 --------------------------------
8593 -- Set_String_Literal_Subtype --
8594 --------------------------------
8602 begin
8616 -- The low bound is set from the low bound of the corresponding
8617 -- index type. Note that we do not store the high bound in the
8618 -- string literal subtype, but it can be deduced if necessary
8619 -- from the length and the low bound.
8623 else
8624 Set_String_Literal_Low_Bound
8628 -- Build bona fide subtype for the string, and wrap it in an
8629 -- unchecked conversion, because the backend expects the
8630 -- String_Literal_Subtype to have a static lower bound.
8632 declare
8638 Right_Opnd =>
8646 begin
8647 Index_Subtype :=
8654 -- In the context, the Index_Type may already have a constraint,
8655 -- so use common base type on string subtype. The base type may
8656 -- be used when generating attributes of the string, for example
8657 -- in the context of a slice assignment.
8682 ------------------------------
8683 -- Simplify_Type_Conversion --
8684 ------------------------------
8687 begin
8689 declare
8694 begin
8696 and then
8703 -- Special processing required if the conversion is the expression
8704 -- of a Truncation attribute reference. In this case we replace:
8706 -- ityp (ftyp'Truncation (x))
8708 -- by
8710 -- ityp (x)
8712 -- with the Float_Truncate flag set, which is more efficient
8714 then
8723 -----------------------------
8724 -- Unique_Fixed_Point_Type --
8725 -----------------------------
8734 -- If true ambiguity, give details
8736 -----------------------
8737 -- Fixed_Point_Error --
8738 -----------------------
8741 begin
8747 -- Start of processing for Unique_Fixed_Point_Type
8749 begin
8750 -- The operations on Duration are visible, so Duration is always a
8751 -- possible interpretation.
8755 -- Look for fixed-point types in enclosing scopes
8764 then
8766 Fixed_Point_Error;
8768 else
8779 -- Look for visible fixed type declarations in the context
8791 then
8793 Fixed_Point_Error;
8795 else
8809 else
8816 ----------------------
8817 -- Valid_Conversion --
8818 ----------------------
8820 function Valid_Conversion
8824 is
8828 function Conversion_Check
8831 -- Little routine to post Msg if Valid is False, returns Valid value
8833 function Valid_Tagged_Conversion
8836 -- Specifically test for validity of tagged conversions
8839 -- Check index and component conformance, and accessibility levels
8840 -- if the component types are anonymous access types (Ada 2005)
8842 ----------------------
8843 -- Conversion_Check --
8844 ----------------------
8846 function Conversion_Check
8849 is
8850 begin
8858 ----------------------------
8859 -- Valid_Array_Conversion --
8860 ----------------------------
8863 is
8878 begin
8879 -- Error if wrong number of dimensions
8881 if
8883 then
8884 Error_Msg_N
8888 -- Number of dimensions matches
8890 else
8891 -- Loop through indexes of the two arrays
8899 -- Error if index types are incompatible
8905 then
8906 Error_Msg_N
8908 Operand);
8916 -- If component types have same base type, all set
8921 -- Here if base types of components are not the same. The only
8922 -- time this is allowed is if we have anonymous access types.
8924 -- The conversion of arrays of anonymous access types can lead
8925 -- to dangling pointers. AI-392 formalizes the accessibility
8926 -- checks that must be applied to such conversions to prevent
8927 -- out-of-scope references.
8929 elsif
8931 or else
8934 and then
8936 then
8939 then
8944 Operand);
8951 -- Conversion not allowed because of accessibility levels
8953 else
8958 else
8962 -- All other cases where component base types do not match
8964 else
8965 Error_Msg_N
8967 Operand);
8971 -- Check that component subtypes statically match. For numeric
8972 -- types this means that both must be either constrained or
8973 -- unconstrained. For enumeration types the bounds must match.
8974 -- All of this is checked in Subtypes_Statically_Match.
8976 if not Subtypes_Statically_Match
8978 then
8979 Error_Msg_N
8988 -----------------------------
8989 -- Valid_Tagged_Conversion --
8990 -----------------------------
8992 function Valid_Tagged_Conversion
8995 is
8996 begin
8997 -- Upward conversions are allowed (RM 4.6(22))
9001 then
9004 -- Downward conversion are allowed if the operand is class-wide
9005 -- (RM 4.6(23)).
9009 then
9014 then
9015 return
9019 -- Ada 2005 (AI-251): The conversion to/from interface types is
9020 -- always valid
9025 -- If the operand is a class-wide type obtained through a limited_
9026 -- with clause, and the context includes the non-limited view, use
9027 -- it to determine whether the conversion is legal.
9033 then
9038 then
9041 else
9042 Error_Msg_NE
9049 -- Start of processing for Valid_Conversion
9051 begin
9055 declare
9062 begin
9063 -- Remove procedure calls, which syntactically cannot appear
9064 -- in this context, but which cannot be removed by type checking,
9065 -- because the context does not impose a type.
9067 -- When compiling for VMS, spurious ambiguities can be produced
9068 -- when arithmetic operations have a literal operand and return
9069 -- System.Address or a descendant of it. These ambiguities are
9070 -- otherwise resolved by the context, but for conversions there
9071 -- is no context type and the removal of the spurious operations
9072 -- must be done explicitly here.
9074 -- The node may be labelled overloaded, but still contain only
9075 -- one interpretation because others were discarded in previous
9076 -- filters. If this is the case, retain the single interpretation
9077 -- if legal.
9085 then
9086 -- More than one candidate interpretation is available
9096 then
9137 -- Numeric types
9141 -- A universal fixed expression can be converted to any numeric type
9146 -- Also no need to check when in an instance or inlined body, because
9147 -- the legality has been established when the template was analyzed.
9148 -- Furthermore, numeric conversions may occur where only a private
9149 -- view of the operand type is visible at the instantiation point.
9150 -- This results in a spurious error if we check that the operand type
9151 -- is a numeric type.
9153 -- Note: in a previous version of this unit, the following tests were
9154 -- applied only for generated code (Comes_From_Source set to False),
9155 -- but in fact the test is required for source code as well, since
9156 -- this situation can arise in source code.
9161 -- Otherwise we need the conversion check
9163 else
9164 return Conversion_Check
9169 -- Array types
9175 then
9176 Error_Msg_N
9179 else
9183 -- Ada 2005 (AI-251): Anonymous access types where target references an
9184 -- interface type.
9187 or else
9190 then
9191 -- Check the static accessibility rule of 4.6(17). Note that the
9192 -- check is not enforced when within an instance body, since the RM
9193 -- requires such cases to be caught at run time.
9198 then
9199 -- In an instance, this is a run-time check, but one we know
9200 -- will fail, so generate an appropriate warning. The raise
9201 -- will be generated by Expand_N_Type_Conversion.
9204 Error_Msg_N
9206 Operand);
9207 Error_Msg_N
9209 else
9210 Error_Msg_N
9212 Operand);
9216 -- Special accessibility checks are needed in the case of access
9217 -- discriminants declared for a limited type.
9221 then
9222 -- When the operand is a selected access discriminant the check
9223 -- needs to be made against the level of the object denoted by
9224 -- the prefix of the selected name. (Object_Access_Level
9225 -- handles checking the prefix of the operand for this case.)
9230 then
9231 -- In an instance, this is a run-time check, but one we
9232 -- know will fail, so generate an appropriate warning.
9233 -- The raise will be generated by Expand_N_Type_Conversion.
9236 Error_Msg_N
9239 Error_Msg_N
9241 else
9242 Error_Msg_N
9249 -- The case of a reference to an access discriminant from
9250 -- within a limited type declaration (which will appear as
9251 -- a discriminal) is always illegal because the level of the
9252 -- discriminant is considered to be deeper than any (nameable)
9253 -- access type.
9260 then
9261 Error_Msg_N
9263 Operand);
9271 -- General and anonymous access types
9275 and then
9276 Conversion_Check
9279 E_Access_Subprogram_Type
9281 E_Access_Protected_Subprogram_Type,
9283 then
9286 then
9287 Error_Msg_N
9292 -- Check the static accessibility rule of 4.6(17). Note that the
9293 -- check is not enforced when within an instance body, since the RM
9294 -- requires such cases to be caught at run time.
9298 then
9301 then
9302 -- In an instance, this is a run-time check, but one we
9303 -- know will fail, so generate an appropriate warning.
9304 -- The raise will be generated by Expand_N_Type_Conversion.
9307 Error_Msg_N
9309 Operand);
9310 Error_Msg_N
9313 else
9314 -- Avoid generation of spurious error message
9317 Error_Msg_N
9319 Operand);
9325 -- Special accessibility checks are needed in the case of access
9326 -- discriminants declared for a limited type.
9330 then
9332 -- When the operand is a selected access discriminant the check
9333 -- needs to be made against the level of the object denoted by
9334 -- the prefix of the selected name. (Object_Access_Level
9335 -- handles checking the prefix of the operand for this case.)
9340 then
9341 -- In an instance, this is a run-time check, but one we
9342 -- know will fail, so generate an appropriate warning.
9343 -- The raise will be generated by Expand_N_Type_Conversion.
9346 Error_Msg_N
9349 Error_Msg_N
9351 Operand);
9353 else
9354 Error_Msg_N
9361 -- The case of a reference to an access discriminant from
9362 -- within a limited type declaration (which will appear as
9363 -- a discriminal) is always illegal because the level of the
9364 -- discriminant is considered to be deeper than any (nameable)
9365 -- access type.
9371 then
9372 Error_Msg_N
9374 Operand);
9380 declare
9382 -- Helper function to handle limited views
9384 --------------------------
9385 -- Full_Designated_Type --
9386 --------------------------
9390 begin
9394 then
9396 else
9407 begin
9411 else
9413 Error_Msg_NE
9418 -- Ada 2005 AI-384: legality rule is symmetric in both
9419 -- designated types. The conversion is legal (with possible
9420 -- constraint check) if either designated type is
9421 -- unconstrained.
9424 or else
9426 and then
9429 then
9432 else
9433 Error_Msg_NE
9441 -- Access to subprogram types. If the operand is an access parameter,
9442 -- the type has a deeper accessibility that any master, and cannot
9443 -- be assigned.
9446 or else
9449 then
9453 then
9454 Error_Msg_N
9456 Operand);
9457 Error_Msg_N
9460 Operand);
9462 Error_Msg_NE
9467 -- Check that the designated types are subtype conformant
9473 -- Check the static accessibility rule of 4.6(20)
9477 then
9478 Error_Msg_N
9480 Operand);
9482 -- Check that if the operand type is declared in a generic body,
9483 -- then the target type must be declared within that same body
9484 -- (enforces last sentence of 4.6(20)).
9487 declare
9493 begin
9500 Error_Msg_N
9509 -- Remote subprogram access types
9513 then
9514 -- It is valid to convert from one RAS type to another provided
9515 -- that their specification statically match.
9517 Check_Subtype_Conformant
9520 Old_Id =>
9522 Err_Loc =>
9523 N);
9526 -- If both are tagged types, check legality of view conversions
9530 then
9533 -- Types derived from the same root type are convertible
9538 -- In an instance or an inlined body, there may be inconsistent
9539 -- views of the same type, or of types derived from a common root.
9542 and then
9545 then
9548 -- Special check for common access type error case
9552 then
9558 else