[flang] Catch attempts to do anything with statement functions other than call them

A statement function in Fortran may be called, but it may not be the target
of a procedure pointer or passed as an actual argument.

1 files changed, 11 insertions, 0 deletions

diff --git a/flang/lib/Semantics/pointer-assignment.cpp b/flang/lib/Semantics/pointer-assignment.cpp
index 69e80e5..54e36f5 100644
--- a/flang/lib/Semantics/pointer-assignment.cpp
+++ b/flang/lib/Semantics/pointer-assignment.cpp
@@ -279,6 +279,17 @@ bool PointerAssignmentChecker::Check(parser::CharBlock rhsName, bool isCall,
 }
 
 bool PointerAssignmentChecker::Check(const evaluate::ProcedureDesignator &d) {
+  if (const Symbol * symbol{d.GetSymbol()}) {
+    if (const auto *subp{
+            symbol->GetUltimate().detailsIf<SubprogramDetails>()}) {
+      if (subp->stmtFunction()) {
+        evaluate::SayWithDeclaration(context_.messages(), *symbol,
+            "Statement function '%s' may not be the target of a pointer assignment"_err_en_US,
+            symbol->name());
+        return false;
+      }
+    }
+  }
   if (auto chars{Procedure::Characterize(d, context_)}) {
     return Check(d.GetName(), false, &*chars, d.GetSpecificIntrinsic());
   } else {