diff --git a/flang/lib/Semantics/resolve-names.cpp b/flang/lib/Semantics/resolve-names.cpp
--- a/flang/lib/Semantics/resolve-names.cpp
+++ b/flang/lib/Semantics/resolve-names.cpp
@@ -3048,7 +3048,8 @@
         details->set_specific(Resolve(name, *specific));
       } else if (isGeneric()) {
         SayAlreadyDeclared(name, *specific);
-      } else if (!specific->has<SubprogramDetails>()) {
+      }
+      if (!specific->has<SubprogramDetails>()) {
         specific->set_details(SubprogramDetails{});
       }
       return specific;
diff --git a/flang/test/Semantics/resolve19.f90 b/flang/test/Semantics/resolve19.f90
--- a/flang/test/Semantics/resolve19.f90
+++ b/flang/test/Semantics/resolve19.f90
@@ -22,3 +22,14 @@
     end subroutine
   end interface
 end module
+
+module m3
+  interface s
+    subroutine s
+    end
+  end interface
+contains
+  !ERROR: 's' is already declared in this scoping unit
+  subroutine s
+  end subroutine
+end