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[flang] Settle ambiguity between C795 and C721

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C721 says that a type parameter value of '*' is permitted in the type-spec
for a named constant; C795 says that such type parameters are allowed
in type-specs only for a few kinds of things, not including named
constants.  The interpretation seems to depend on context, with C721
applying to intrinsic types (i.e., character) and C795 applying only
to derived types.

Differential Revision: https://reviews.llvm.org/D146586
This commit is contained in:
Peter Klausler
2023-03-17 17:16:40 -07:00
parent 7b0c41841e
commit 41a964cff0
6 changed files with 24 additions and 19 deletions
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12
flang/lib/Semantics/check-declarations.cpp
View File

@@ -190,9 +190,7 @@ void CheckHelper::Check(const ParamValue &value, bool canBeAssumed) {
if (value.isAssumed()) {
if (!canBeAssumed) { // C795, C721, C726
messages_.Say(
"An assumed (*) type parameter may be used only for a (non-statement"
" function) dummy argument, associate name, named constant, or"
" external function result"_err_en_US);
"An assumed (*) type parameter may be used only for a (non-statement function) dummy argument, associate name, character named constant, or external function result"_err_en_US);
}
} else {
CheckSpecExpr(value.GetExplicit());
@@ -323,8 +321,9 @@ void CheckHelper::Check(const Symbol &symbol) {
"A dummy procedure of a pure subprogram must be pure"_err_en_US);
}
}
if (type) { // Section 7.2, paragraph 7
bool canHaveAssumedParameter{IsNamedConstant(symbol) ||
if (type) { // Section 7.2, paragraph 7; C795
bool isChar{type->category() == DeclTypeSpec::Character};
bool canHaveAssumedParameter{(isChar && IsNamedConstant(symbol)) ||
(IsAssumedLengthCharacter(symbol) && // C722
(IsExternal(symbol) ||
ClassifyProcedure(symbol) ==
@@ -333,8 +332,7 @@ void CheckHelper::Check(const Symbol &symbol) {
if (!IsStmtFunctionDummy(symbol)) { // C726
if (const auto *object{symbol.detailsIf<ObjectEntityDetails>()}) {
canHaveAssumedParameter |= object->isDummy() ||
(object->isFuncResult() &&
type->category() == DeclTypeSpec::Character) ||
(isChar && object->isFuncResult()) ||
IsStmtFunctionResult(symbol); // Avoids multiple messages
} else {
canHaveAssumedParameter |= symbol.has<AssocEntityDetails>();

4
flang/test/Semantics/call05.f90
View File

@@ -20,9 +20,9 @@ module m
class(t2), allocatable :: pa2(:)
class(*), pointer :: up(:)
class(*), allocatable :: ua(:)
!ERROR: An assumed (*) type parameter may be used only for a (non-statement function) dummy argument, associate name, named constant, or external function result
!ERROR: An assumed (*) type parameter may be used only for a (non-statement function) dummy argument, associate name, character named constant, or external function result
type(pdt(*)), pointer :: amp(:)
!ERROR: An assumed (*) type parameter may be used only for a (non-statement function) dummy argument, associate name, named constant, or external function result
!ERROR: An assumed (*) type parameter may be used only for a (non-statement function) dummy argument, associate name, character named constant, or external function result
type(pdt(*)), allocatable :: ama(:)
type(pdt(:)), pointer :: dmp(:)
type(pdt(:)), allocatable :: dma(:)

2
flang/test/Semantics/call31.f90
View File

@@ -6,7 +6,7 @@
subroutine subr(parg)
!PORTABILITY: A dummy procedure pointer should not have assumed-length CHARACTER(*) result type
procedure(character(*)), pointer :: parg
!ERROR: An assumed (*) type parameter may be used only for a (non-statement function) dummy argument, associate name, named constant, or external function result
!ERROR: An assumed (*) type parameter may be used only for a (non-statement function) dummy argument, associate name, character named constant, or external function result
procedure(character(*)), pointer :: plocal
print *, parg()
plocal => parg

13
flang/test/Semantics/resolve73.f90
View File

@@ -2,17 +2,18 @@
! C721 A type-param-value of * shall be used only
! * to declare a dummy argument,
! * to declare a named constant,
! * in the type-spec of an ALLOCATE statement wherein each allocate-object is
! * in the type-spec of an ALLOCATE statement wherein each allocate-object is
! a dummy argument of type CHARACTER with an assumed character length,
! * in the type-spec or derived-type-spec of a type guard statement (11.1.11),
! * in the type-spec or derived-type-spec of a type guard statement (11.1.11),
! or
! * in an external function, to declare the character length parameter of the function result.
! Note also C795 for derived types (C721 applies to intrinsic types)
subroutine s(arg)
character(len=*), pointer :: arg
character*(*), parameter :: cvar1 = "abc"
character*4, cvar2
character(len=4_4) :: cvar3
!ERROR: An assumed (*) type parameter may be used only for a (non-statement function) dummy argument, associate name, named constant, or external function result
!ERROR: An assumed (*) type parameter may be used only for a (non-statement function) dummy argument, associate name, character named constant, or external function result
character(len=*) :: cvar4
type derived(param)
@@ -26,6 +27,12 @@ subroutine s(arg)
end function fun
end interface
type t(len)
integer, len :: len
end type
!ERROR: An assumed (*) type parameter may be used only for a (non-statement function) dummy argument, associate name, character named constant, or external function result
type(t(*)), parameter :: p2 = t(123)() ! C795
select type (ax => a%x)
type is (integer)
print *, "hello"

8
flang/test/Semantics/resolve74.f90
View File

@@ -10,7 +10,7 @@ subroutine s()
type(derived(34)) :: a
procedure(character(len=*)) :: externCharFunc
!ERROR: An assumed (*) type parameter may be used only for a (non-statement function) dummy argument, associate name, named constant, or external function result
!ERROR: An assumed (*) type parameter may be used only for a (non-statement function) dummy argument, associate name, character named constant, or external function result
procedure(type(derived(param =*))) :: externDerivedFunc
interface
@@ -24,14 +24,14 @@ subroutine s()
type(derived(param=4)) :: works
end function works
!ERROR: An assumed (*) type parameter may be used only for a (non-statement function) dummy argument, associate name, named constant, or external function result
!ERROR: An assumed (*) type parameter may be used only for a (non-statement function) dummy argument, associate name, character named constant, or external function result
function fails1()
character(len=*) :: fails1
end function fails1
!ERROR: An assumed (*) type parameter may be used only for a (non-statement function) dummy argument, associate name, named constant, or external function result
!ERROR: An assumed (*) type parameter may be used only for a (non-statement function) dummy argument, associate name, character named constant, or external function result
function fails2()
!ERROR: An assumed (*) type parameter may be used only for a (non-statement function) dummy argument, associate name, named constant, or external function result
!ERROR: An assumed (*) type parameter may be used only for a (non-statement function) dummy argument, associate name, character named constant, or external function result
type(derived(param=*)) :: fails2
end function fails2

4
flang/test/Semantics/resolve75.f90
View File

@@ -7,8 +7,8 @@ subroutine s()
implicit character(len=*) (d)
stmtFunc1 (x) = x * 32
cStmtFunc2 (x) = "abc"
!ERROR: An assumed (*) type parameter may be used only for a (non-statement function) dummy argument, associate name, named constant, or external function result
!ERROR: An assumed (*) type parameter may be used only for a (non-statement function) dummy argument, associate name, character named constant, or external function result
cStmtFunc3 (dummy) = "abc"
!ERROR: An assumed (*) type parameter may be used only for a (non-statement function) dummy argument, associate name, named constant, or external function result
!ERROR: An assumed (*) type parameter may be used only for a (non-statement function) dummy argument, associate name, character named constant, or external function result
dStmtFunc3 (x) = "abc"
end subroutine s