[flang] Whether a procedure's interface is explicit or not is not a d…

[klausler]

…istinguishing characteristic

We note whether a procedure's interface is explicit or implicit as an attribute of its characteristics, so that other semantics can be checked appropriately, but this internal attribute should not be used as a distinguishing characteristic in itself.

Fixes #81876.

[llvmbot]

@llvm/pr-subscribers-flang-semantics

Author: Peter Klausler (klausler)

Changes

…istinguishing characteristic

We note whether a procedure's interface is explicit or implicit as an attribute of its characteristics, so that other semantics can be checked appropriately, but this internal attribute should not be used as a distinguishing characteristic in itself.

Fixes #81876.

---

Full diff: https://github.com/llvm/llvm-project/pull/82796.diff

3 Files Affected:

• (modified) flang/lib/Evaluate/characteristics.cpp (+1)
• (modified) flang/test/Semantics/call35.f90 (+1-1)
• (modified) flang/test/Semantics/null-init.f90 (+1-1)

diff --git a/flang/lib/Evaluate/characteristics.cpp b/flang/lib/Evaluate/characteristics.cpp
index 80b0f346c32d38..cf8b16c0ead6cd 100644
--- a/flang/lib/Evaluate/characteristics.cpp
+++ b/flang/lib/Evaluate/characteristics.cpp
@@ -1265,6 +1265,7 @@ bool Procedure::IsCompatibleWith(const Procedure &actual, std::string *whyNot,
   }
   Attrs differences{attrs ^ actualAttrs};
   differences.reset(Attr::Subroutine); // dealt with specifically later
+  differences.reset(Attr::ImplicitInterface);
   if (!differences.empty()) {
     if (whyNot) {
       auto sep{": "s};
diff --git a/flang/test/Semantics/call35.f90 b/flang/test/Semantics/call35.f90
index ff819481226d62..81a0ecb04da536 100644
--- a/flang/test/Semantics/call35.f90
+++ b/flang/test/Semantics/call35.f90
@@ -12,7 +12,7 @@ subroutine s2
 
 subroutine s3
   interface
-    !WARNING: The global subprogram 'ext' is not compatible with its local procedure declaration (incompatible procedure attributes: ImplicitInterface)
+    !WARNING: The global subprogram 'ext' is not compatible with its local procedure declaration (distinct numbers of dummy arguments)
     subroutine ext(n)
       integer n
     end
diff --git a/flang/test/Semantics/null-init.f90 b/flang/test/Semantics/null-init.f90
index ad3f91679a4272..ad2fa511f9ff3f 100644
--- a/flang/test/Semantics/null-init.f90
+++ b/flang/test/Semantics/null-init.f90
@@ -37,7 +37,7 @@ module m6
 
 module m7
   interface
-    !WARNING: The external interface 'null' is not compatible with an earlier definition (incompatible procedure attributes: ImplicitInterface)
+    !WARNING: The external interface 'null' is not compatible with an earlier definition (function results have incompatible attributes)
     function null() result(p)
       integer, pointer :: p
     end function

[vzakhari]

LGTM