[Clang] Skip deleted function body on error

Author: Sirraide

clang/include/clang/Parse/Parser.h

@@ -1601,6 +1601,7 @@ class Parser : public CodeCompletionHandler {
                                      const VirtSpecifiers &VS,
                                      SourceLocation PureSpecLoc);
   StringLiteral *ParseCXXDeletedFunctionMessage();
+  void SkipDeletedFunctionBody();
   void ParseCXXNonStaticMemberInitializer(Decl *VarD);
   void ParseLexedAttributes(ParsingClass &Class);
   void ParseLexedAttributeList(LateParsedAttrList &LAs, Decl *D,

clang/lib/Parse/ParseCXXInlineMethods.cpp

@@ -42,6 +42,22 @@ StringLiteral *Parser::ParseCXXDeletedFunctionMessage() {
   return Message;
 }
 
+/// If we've encountered '= delete' in a context where it is ill-formed, such
+/// as in the declaration of a non-function, also skip the ("message") part if
+/// it is present to avoid issuing further diagnostics.
+void Parser::SkipDeletedFunctionBody() {
+  if (!Tok.is(tok::l_paren))
+    return;
+
+  BalancedDelimiterTracker BT{*this, tok::l_paren};
+  BT.consumeOpen();
+
+  // Just skip to the end of the current declaration.
+  SkipUntil(tok::r_paren, tok::comma, StopAtSemi | StopBeforeMatch);
+  if (Tok.is(tok::r_paren))
+    BT.consumeClose();
+}
+
 /// ParseCXXInlineMethodDef - We parsed and verified that the specified
 /// Declarator is a well formed C++ inline method definition. Now lex its body
 /// and store its tokens for parsing after the C++ class is complete.

clang/lib/Parse/ParseDecl.cpp

@@ -2676,6 +2676,7 @@ Decl *Parser::ParseDeclarationAfterDeclaratorAndAttributes(
           << 1 /* delete */;
       else
         Diag(ConsumeToken(), diag::err_deleted_non_function);
+      SkipDeletedFunctionBody();
     } else if (Tok.is(tok::kw_default)) {
       if (D.isFunctionDeclarator())
         Diag(ConsumeToken(), diag::err_default_delete_in_multiple_declaration)

clang/lib/Parse/ParseDeclCXX.cpp

@@ -3397,6 +3397,7 @@ ExprResult Parser::ParseCXXMemberInitializer(Decl *D, bool IsFunction,
               << 1 /* delete */;
         else
           Diag(ConsumeToken(), diag::err_deleted_non_function);
+        SkipDeletedFunctionBody();
         return ExprError();
       }
     } else if (Tok.is(tok::kw_default)) {

clang/test/Parser/cxx2c-delete-with-message.cpp

@@ -33,3 +33,16 @@ void c() = delete(); // expected-error {{expected string literal}}
 void d() = delete(42); // expected-error {{expected string literal}}
 void e() = delete("foo"[0]); // expected-error {{expected ')'}} expected-note {{to match this '('}} // pre26-warning {{'= delete' with a message is a C++2c extension}} compat-warning {{'= delete' with a message is incompatible with C++ standards before C++2c}}
 void f() = delete("foo"); // pre26-warning {{'= delete' with a message is a C++2c extension}} compat-warning {{'= delete' with a message is incompatible with C++ standards before C++2c}}
+
+namespace CWG2876 {
+using T = void ();
+using U = int;
+
+T a = delete ("hello"); // expected-error {{only functions can have deleted definitions}}
+U b = delete ("hello"), c, d = delete ("hello"); // expected-error 2 {{only functions can have deleted definitions}}
+
+struct C {
+  T e = delete ("hello"); // expected-error {{'= delete' is a function definition and must occur in a standalone declaration}}
+  U f = delete ("hello"); // expected-error {{cannot delete expression of type 'const char[6]'}}
+};
+}