Implement the GNU semantics for forward declarations of enum types in
C and C++. Fixes PR3688.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@66282 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/Basic/DiagnosticSemaKinds.def b/include/clang/Basic/DiagnosticSemaKinds.def
index ef6f7ee..26a6ab7 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.def
+++ b/include/clang/Basic/DiagnosticSemaKinds.def
@@ -676,6 +676,8 @@
"use of %0 with tag type that does not match previous declaration")
DIAG(ext_forward_ref_enum, EXTENSION,
"ISO C forbids forward references to 'enum' types")
+DIAG(err_forward_ref_enum, ERROR,
+ "ISO C++ forbids forward references to 'enum' types")
DIAG(err_redefinition_of_enumerator, ERROR,
"redefinition of enumerator %0")
DIAG(err_duplicate_member, ERROR,
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 953e39f..f4c2788 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -2976,8 +2976,8 @@
}
}
} else if (TK == TK_Reference && SS.isEmpty() && Name &&
- (Kind != TagDecl::TK_enum)) {
- // C++ [basic.scope.pdecl]p5:
+ (Kind != TagDecl::TK_enum || !getLangOptions().CPlusPlus)) {
+ // C.scope.pdecl]p5:
// -- for an elaborated-type-specifier of the form
//
// class-key identifier
@@ -2993,7 +2993,10 @@
//
// C99 6.7.2.3p8 has a similar (but not identical!) provision for
// C structs and unions.
-
+ //
+ // GNU C also supports this behavior as part of its incomplete
+ // enum types extension, while GNU C++ does not.
+ //
// Find the context where we'll be declaring the tag.
// FIXME: We would like to maintain the current DeclContext as the
// lexical context,
@@ -3027,7 +3030,11 @@
New = EnumDecl::Create(Context, SearchDC, Loc, Name,
cast_or_null<EnumDecl>(PrevDecl));
// If this is an undefined enum, warn.
- if (TK != TK_Definition) Diag(Loc, diag::ext_forward_ref_enum);
+ if (TK != TK_Definition && !Invalid) {
+ unsigned DK = getLangOptions().CPlusPlus? diag::err_forward_ref_enum
+ : diag::ext_forward_ref_enum;
+ Diag(Loc, DK);
+ }
} else {
// struct/union/class
diff --git a/test/Sema/enum.c b/test/Sema/enum.c
index 55ddb0d..ce49f30 100644
--- a/test/Sema/enum.c
+++ b/test/Sema/enum.c
@@ -73,3 +73,14 @@
enum NotYetComplete { // expected-note{{definition of 'enum NotYetComplete' is not complete until the closing '}'}}
NYC1 = sizeof(enum NotYetComplete) // expected-error{{invalid application of 'sizeof' to an incomplete type 'enum NotYetComplete'}}
};
+
+/// PR3688
+struct s1 {
+ enum e1 (*bar)(void); // expected-warning{{ISO C forbids forward references to 'enum' types}}
+};
+
+enum e1 { YES, NO };
+
+static enum e1 badfunc(struct s1 *q) {
+ return q->bar();
+}
diff --git a/test/SemaCXX/enum.cpp b/test/SemaCXX/enum.cpp
index 7626e4a..c7748c3 100644
--- a/test/SemaCXX/enum.cpp
+++ b/test/SemaCXX/enum.cpp
@@ -23,3 +23,18 @@
Foo myvar = A;
myvar = B;
}
+
+/// PR3688
+struct s1 {
+ enum e1 (*bar)(void); // expected-error{{ISO C++ forbids forward references to 'enum' types}}
+};
+
+enum e1 { YES, NO };
+
+static enum e1 badfunc(struct s1 *q) {
+ // FIXME: the message below should probably give context information
+ // in those types.
+ return q->bar(); // expected-error{{incompatible type returning 'enum e1', expected 'enum e1'}}
+}
+
+enum e2; // expected-error{{ISO C++ forbids forward references to 'enum' types}}