Silence duplicate diagnostics because parsing of a standards-based attribute triggers parsing diagnostics that may also be picked up during semantic analysis.

llvm-svn: 262960

clang/lib/Parse/ParseDeclCXX.cpp

@@ -3695,6 +3695,7 @@ bool Parser::ParseCXX11AttributeArgs(IdentifierInfo *AttrName,
         // The attribute was allowed to have arguments, but none were provided
         // even though the attribute parsed successfully. This is an error.
         Diag(LParenLoc, diag::err_attribute_requires_arguments) << AttrName;
+        Attr->setInvalid(true);
       } else if (!Attr->getMaxArgs()) {
         // The attribute parsed successfully, but was not allowed to have any
         // arguments. It doesn't matter whether any were provided -- the
@@ -3702,6 +3703,7 @@ bool Parser::ParseCXX11AttributeArgs(IdentifierInfo *AttrName,
         Diag(LParenLoc, diag::err_cxx11_attribute_forbids_arguments)
             << AttrName
             << FixItHint::CreateRemoval(SourceRange(LParenLoc, *EndLoc));
+        Attr->setInvalid(true);
       }
     }
   }

clang/test/CXX/dcl.dcl/dcl.attr/dcl.attr.nodiscard/p1.cpp

@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 -fsyntax-only -std=c++1z -verify %s
+
+struct [[nodiscard]] S1 {}; // ok
+struct [[nodiscard nodiscard]] S2 {}; // expected-error {{attribute 'nodiscard' cannot appear multiple times in an attribute specifier}}
+struct [[nodiscard("Wrong")]] S3 {}; // expected-error {{'nodiscard' cannot have an argument list}}
+
+[[nodiscard]] int f();
+enum [[nodiscard]] E {};

clang/test/Parser/cxx0x-attributes.cpp

@@ -336,7 +336,6 @@ namespace {
   // expected-warning@-1 {{use of the 'deprecated' attribute is a C++14 extension}}
   [[deprecated()]] void foo();
   // expected-error@-1 {{parentheses must be omitted if 'deprecated' attribute's argument list is empty}}
-  // expected-warning@-2 {{use of the 'deprecated' attribute is a C++14 extension}}
   [[gnu::deprecated()]] void quux();
 }