[flang-commits] [flang] [Flang] Reject keyword arguments in statement function calls (PR #198610)
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Sun May 31 04:40:40 PDT 2026
https://github.com/blazie2004 updated https://github.com/llvm/llvm-project/pull/198610
>From b4a5db0d39f7572689ae2fc56db597970d1b40b9 Mon Sep 17 00:00:00 2001
From: Jay Satish Kumar Patel <kumarpat at pe31.hpc.amslabs.hpecorp.net>
Date: Tue, 19 May 2026 13:44:07 -0500
Subject: [PATCH 1/3] Reject keyword arguments in statement function calls
---
flang/lib/Evaluate/characteristics.cpp | 4 ++++
flang/test/Semantics/call47.f90 | 15 +++++++++++++++
2 files changed, 19 insertions(+)
create mode 100644 flang/test/Semantics/call47.f90
diff --git a/flang/lib/Evaluate/characteristics.cpp b/flang/lib/Evaluate/characteristics.cpp
index 63d4c74d553e3..ba11412511638 100644
--- a/flang/lib/Evaluate/characteristics.cpp
+++ b/flang/lib/Evaluate/characteristics.cpp
@@ -642,6 +642,10 @@ static std::optional<Procedure> CharacterizeProcedure(
[&](const semantics::SubprogramDetails &subp)
-> std::optional<Procedure> {
Procedure result;
+ if (subp.stmtFunction()) {
+ // Statement functions have implicit interfaces (F'2018 15.5.1)
+ result.attrs.set(Procedure::Attr::ImplicitInterface);
+ }
if (subp.isFunction()) {
if (auto fr{CharacterizeFunctionResult(
subp.result(), context, seenProcs, emitError)}) {
diff --git a/flang/test/Semantics/call47.f90 b/flang/test/Semantics/call47.f90
new file mode 100644
index 0000000000000..e2b775a60526c
--- /dev/null
+++ b/flang/test/Semantics/call47.f90
@@ -0,0 +1,15 @@
+! RUN: %python %S/test_errors.py %s %flang_fc1
+! Test F'2018 15.5.1 C1535 - keyword arguments are not allowed when the
+! interface is implicit. Statement functions have implicit interfaces.
+
+program test_stmt_func_keyword
+ integer :: f1, x, c
+
+ ! Statement function definition
+ f1(x) = x / 2
+
+ ! Calling a statement function with a keyword argument is not allowed
+ ! because statement functions have implicit interfaces.
+ !ERROR: Keyword 'x=' may not appear in a reference to a procedure with an implicit interface
+ c = f1(x=10)
+end program
>From 1357ddcced5c7953c4c47dc93adb293db3d79456 Mon Sep 17 00:00:00 2001
From: Jay Satish Kumar Patel <kumarpat at pe31.hpc.amslabs.hpecorp.net>
Date: Wed, 20 May 2026 12:49:15 -0500
Subject: [PATCH 2/3] Handle implicit interface checks for statement functions
---
flang/lib/Evaluate/characteristics.cpp | 4 ----
flang/lib/Semantics/check-call.cpp | 2 +-
flang/lib/Semantics/check-call.h | 5 +++++
flang/lib/Semantics/expression.cpp | 15 +++++++++++++++
4 files changed, 21 insertions(+), 5 deletions(-)
diff --git a/flang/lib/Evaluate/characteristics.cpp b/flang/lib/Evaluate/characteristics.cpp
index ba11412511638..63d4c74d553e3 100644
--- a/flang/lib/Evaluate/characteristics.cpp
+++ b/flang/lib/Evaluate/characteristics.cpp
@@ -642,10 +642,6 @@ static std::optional<Procedure> CharacterizeProcedure(
[&](const semantics::SubprogramDetails &subp)
-> std::optional<Procedure> {
Procedure result;
- if (subp.stmtFunction()) {
- // Statement functions have implicit interfaces (F'2018 15.5.1)
- result.attrs.set(Procedure::Attr::ImplicitInterface);
- }
if (subp.isFunction()) {
if (auto fr{CharacterizeFunctionResult(
subp.result(), context, seenProcs, emitError)}) {
diff --git a/flang/lib/Semantics/check-call.cpp b/flang/lib/Semantics/check-call.cpp
index da8880482d4dc..dcd7dc4288f6f 100644
--- a/flang/lib/Semantics/check-call.cpp
+++ b/flang/lib/Semantics/check-call.cpp
@@ -27,7 +27,7 @@ namespace characteristics = Fortran::evaluate::characteristics;
namespace Fortran::semantics {
-static void CheckImplicitInterfaceArg(evaluate::ActualArgument &arg,
+void CheckImplicitInterfaceArg(evaluate::ActualArgument &arg,
parser::ContextualMessages &messages, SemanticsContext &context) {
auto restorer{
messages.SetLocation(arg.sourceLocation().value_or(messages.at()))};
diff --git a/flang/lib/Semantics/check-call.h b/flang/lib/Semantics/check-call.h
index a69b792b646e6..fb021d23dabc8 100644
--- a/flang/lib/Semantics/check-call.h
+++ b/flang/lib/Semantics/check-call.h
@@ -25,6 +25,11 @@ namespace Fortran::semantics {
class Scope;
class SemanticsContext;
+// Check constraints on actual arguments for procedures with implicit
+// interfaces. Used for statement function calls and external procedures.
+void CheckImplicitInterfaceArg(evaluate::ActualArgument &,
+ parser::ContextualMessages &, SemanticsContext &);
+
// Argument treatingExternalAsImplicit should be true when the called procedure
// does not actually have an explicit interface at the call site, but
// its characteristics are known because it is a subroutine or function
diff --git a/flang/lib/Semantics/expression.cpp b/flang/lib/Semantics/expression.cpp
index 8ee0613bdfc5f..24b5cfa8c1f75 100644
--- a/flang/lib/Semantics/expression.cpp
+++ b/flang/lib/Semantics/expression.cpp
@@ -3769,6 +3769,10 @@ std::optional<characteristics::Procedure> ExpressionAnalyzer::CheckCall(
bool treatExternalAsImplicit{
IsExternalCalledImplicitly(callSite, proc.GetSymbol())};
const Symbol *procSymbol{proc.GetSymbol()};
+ // Statement functions have implicit interfaces and require the same checks
+ bool isStatementFunction{procSymbol &&
+ procSymbol->has<semantics::SubprogramDetails>() &&
+ procSymbol->get<semantics::SubprogramDetails>().stmtFunction()};
std::optional<characteristics::Procedure> chars;
if (procSymbol && procSymbol->has<semantics::ProcEntityDetails>() &&
procSymbol->owner().IsGlobal()) {
@@ -3838,6 +3842,17 @@ std::optional<characteristics::Procedure> ExpressionAnalyzer::CheckCall(
name, DEREF(pure->symbol()).name());
}
}
+ if (isStatementFunction) {
+ // Statement functions have implicit interfaces; check for
+ // keyword arguments and other implicit interface constraints
+ parser::ContextualMessages &messages{
+ context_.foldingContext().messages()};
+ for (auto &arg : arguments) {
+ if (arg) {
+ semantics::CheckImplicitInterfaceArg(*arg, messages, context_);
+ }
+ }
+ }
ok &= semantics::CheckArguments(*chars, arguments, context_,
context_.FindScope(callSite), treatExternalAsImplicit,
/*ignoreImplicitVsExplicit=*/false, specificIntrinsic);
>From 5f864bdc39995a8ff41e3da69b3c2fce3b3a4c22 Mon Sep 17 00:00:00 2001
From: Jay Satish Kumar Patel <kumarpat at pe31.hpc.amslabs.hpecorp.net>
Date: Sun, 31 May 2026 06:35:23 -0500
Subject: [PATCH 3/3] use canonical flag check, add tests for wrong keyword and
two-arg function
---
flang/lib/Semantics/expression.cpp | 3 +--
flang/test/Semantics/call47.f90 | 17 ++++++++++++++---
2 files changed, 15 insertions(+), 5 deletions(-)
diff --git a/flang/lib/Semantics/expression.cpp b/flang/lib/Semantics/expression.cpp
index 24b5cfa8c1f75..a9e7bcc11ab34 100644
--- a/flang/lib/Semantics/expression.cpp
+++ b/flang/lib/Semantics/expression.cpp
@@ -3771,8 +3771,7 @@ std::optional<characteristics::Procedure> ExpressionAnalyzer::CheckCall(
const Symbol *procSymbol{proc.GetSymbol()};
// Statement functions have implicit interfaces and require the same checks
bool isStatementFunction{procSymbol &&
- procSymbol->has<semantics::SubprogramDetails>() &&
- procSymbol->get<semantics::SubprogramDetails>().stmtFunction()};
+ procSymbol->flags().test(Symbol::Flag::StmtFunction)};
std::optional<characteristics::Procedure> chars;
if (procSymbol && procSymbol->has<semantics::ProcEntityDetails>() &&
procSymbol->owner().IsGlobal()) {
diff --git a/flang/test/Semantics/call47.f90 b/flang/test/Semantics/call47.f90
index e2b775a60526c..0c6e9071f33f0 100644
--- a/flang/test/Semantics/call47.f90
+++ b/flang/test/Semantics/call47.f90
@@ -1,15 +1,26 @@
! RUN: %python %S/test_errors.py %s %flang_fc1
-! Test F'2018 15.5.1 C1535 - keyword arguments are not allowed when the
+! Test F2018 15.5.1 C1535 - keyword arguments are not allowed when the
! interface is implicit. Statement functions have implicit interfaces.
program test_stmt_func_keyword
- integer :: f1, x, c
+ integer :: f1, f2, x, y, c
- ! Statement function definition
+ ! Statement function definitions
f1(x) = x / 2
+ f2(x, y) = x + y
! Calling a statement function with a keyword argument is not allowed
! because statement functions have implicit interfaces.
!ERROR: Keyword 'x=' may not appear in a reference to a procedure with an implicit interface
c = f1(x=10)
+
+ ! Wrong keyword name - gets both implicit interface error and unrecognized keyword error
+ !ERROR: Keyword 'y=' may not appear in a reference to a procedure with an implicit interface
+ !ERROR: Argument keyword 'y=' is not recognized for this procedure reference
+ c = f1(y=10)
+
+ ! Two keyword arguments - each gets its own diagnostic
+ !ERROR: Keyword 'x=' may not appear in a reference to a procedure with an implicit interface
+ !ERROR: Keyword 'y=' may not appear in a reference to a procedure with an implicit interface
+ c = f2(x=10, y=20)
end program
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