Add test coverage

Author: AaronBallman

clang/lib/AST/ASTStructuralEquivalence.cpp

@@ -2103,13 +2103,16 @@ static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
                           diag::err_odr_tag_type_inconsistent))
             << Context.ToCtx.getTypeDeclType(D2)
             << (&Context.FromCtx != &Context.ToCtx);
-        EnumDecl *Has = D1->isFixed() ? D1 : D2;
-        EnumDecl *Missing = D1->isFixed() ? D1 : D2;
-        Context.Diag1(Has->getLocation(), diag::note_odr_fixed_underlying_type)
-            << Has;
-        Context.Diag2(Missing->getLocation(),
-                      diag::note_odr_missing_fixed_underlying_type)
-            << Missing;
+        Context.Diag1(D1->getLocation(),
+                      D1->isFixed()
+                          ? diag::note_odr_fixed_underlying_type
+                          : diag::note_odr_missing_fixed_underlying_type)
+            << D1;
+        Context.Diag2(D2->getLocation(),
+                      D2->isFixed()
+                          ? diag::note_odr_fixed_underlying_type
+                          : diag::note_odr_missing_fixed_underlying_type)
+            << D2;
       }
       return false;
     }
@@ -2123,7 +2126,7 @@ static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
                             diag::err_odr_tag_type_inconsistent))
               << Context.ToCtx.getTypeDeclType(D2)
               << (&Context.FromCtx != &Context.ToCtx);
-          Context.Diag1(D2->getLocation(), diag::note_odr_enumerator)
+          Context.Diag2(D2->getLocation(), diag::note_odr_enumerator)
               << D2 << D2->getIntegerType() << D1->getIntegerType();
         }
         return false;

clang/test/ASTMerge/enum/Inputs/enum3.c

@@ -0,0 +1,14 @@
+// [C23] missing underlying types
+enum E1 : int {
+  E1Enumerator1
+};
+
+enum E2 {
+  E2Enumerator1
+};
+
+// [C23] Incompatible underlying types
+enum E3 : long {
+  E3Enumerator1
+};
+

clang/test/ASTMerge/enum/Inputs/enum4.c

@@ -0,0 +1,14 @@
+// [C23] missing underlying types
+enum E1 {
+  E1Enumerator1
+};
+
+enum E2 : int {
+  E2Enumerator1
+};
+
+// [C23] Incompatible underlying types
+enum E3 : short {
+  E3Enumerator1
+};
+

clang/test/ASTMerge/enum/test2.c

@@ -0,0 +1,16 @@
+// RUN: %clang_cc1 -std=c23 -emit-pch -o %t.1.ast %S/Inputs/enum3.c
+// RUN: %clang_cc1 -std=c23 -emit-pch -o %t.2.ast %S/Inputs/enum4.c
+// RUN: not %clang_cc1 -std=c23 -ast-merge %t.1.ast -ast-merge %t.2.ast -fsyntax-only %s 2>&1 | FileCheck %s
+
+// FIXME: this error should not happen!
+// CHECK: error: type 'struct __NSConstantString_tag' has an attribute which currently causes the types to be treated as though they are incompatible
+// CHECK: enum3.c:2:6: warning: type 'enum E1' has incompatible definitions in different translation units
+// CHECK: enum4.c:2:6: note: enumeration 'E1' missing fixed underlying type here
+// CHECK: enum3.c:2:6: note: enumeration 'E1' has fixed underlying type here
+// CHECK: enum3.c:6:6: warning: type 'enum E2' has incompatible definitions in different translation units
+// CHECK: enum4.c:6:6: note: enumeration 'E2' has fixed underlying type here
+// CHECK: enum3.c:6:6: note: enumeration 'E2' missing fixed underlying type here
+// CHECK: enum3.c:11:6: warning: type 'enum E3' has incompatible definitions in different translation units
+// CHECK: enum3.c:11:6: note: enumerator 'E3' with value 'long' here
+// CHECK: 3 warnings and 1 error generated
+