Gracefully handle an attribute specifier following a lambda introducer when the parameter list wasn't present.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@203565 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 21 insertions, 7 deletions

diff --git a/include/clang/Basic/DiagnosticParseKinds.td b/include/clang/Basic/DiagnosticParseKinds.td
index 5be34dc188..573748f37b 100644
--- a/include/clang/Basic/DiagnosticParseKinds.td
+++ b/include/clang/Basic/DiagnosticParseKinds.td
@@ -725,7 +725,8 @@ def warn_cxx98_compat_lambda : Warning<
   "lambda expressions are incompatible with C++98">,
   InGroup<CXX98Compat>, DefaultIgnore;
 def err_lambda_missing_parens : Error<
-  "lambda requires '()' before %select{'mutable'|return type}0">;
+  "lambda requires '()' before %select{'mutable'|return type|"
+  "attribute specifier}0">;
 
 // Availability attribute
 def err_expected_version : Error<
diff --git a/lib/Parse/ParseExprCXX.cpp b/lib/Parse/ParseExprCXX.cpp
index 6fd920e7e8..439fb077da 100644
--- a/lib/Parse/ParseExprCXX.cpp
+++ b/lib/Parse/ParseExprCXX.cpp
@@ -1066,11 +1066,20 @@ ExprResult Parser::ParseLambdaExpressionAfterIntroducer(
                                            LParenLoc, FunLocalRangeEnd, D,
                                            TrailingReturnType),
                   Attr, DeclEndLoc);
-  } else if (Tok.is(tok::kw_mutable) || Tok.is(tok::arrow)) {
-    // It's common to forget that one needs '()' before 'mutable' or the 
-    // result type. Deal with this.
+  } else if (Tok.is(tok::kw_mutable) || Tok.is(tok::arrow) ||
+             (Tok.is(tok::l_square) && NextToken().is(tok::l_square))) {
+    // It's common to forget that one needs '()' before 'mutable', an attribute
+    // specifier, or the result type. Deal with this.
+    unsigned TokKind = 0;
+    switch (Tok.getKind()) {
+    case tok::kw_mutable: TokKind = 0; break;
+    case tok::arrow: TokKind = 1; break;
+    case tok::l_square: TokKind = 2; break;
+    default: llvm_unreachable("Unknown token kind");
+    }
+
     Diag(Tok, diag::err_lambda_missing_parens)
-      << Tok.is(tok::arrow)
+      << TokKind
       << FixItHint::CreateInsertion(Tok.getLocation(), "() ");
     SourceLocation DeclLoc = Tok.getLocation();
     SourceLocation DeclEndLoc = DeclLoc;
@@ -1081,7 +1090,11 @@ ExprResult Parser::ParseLambdaExpressionAfterIntroducer(
       MutableLoc = ConsumeToken();
       DeclEndLoc = MutableLoc;
     }
-    
+
+    // Parse attribute-specifier[opt].
+    ParsedAttributes Attr(AttrFactory);
+    MaybeParseCXX11Attributes(Attr, &DeclEndLoc);
+
     // Parse the return type, if there is one.
     TypeResult TrailingReturnType;
     if (Tok.is(tok::arrow)) {
@@ -1091,7 +1104,6 @@ ExprResult Parser::ParseLambdaExpressionAfterIntroducer(
         DeclEndLoc = Range.getEnd();      
     }
 
-    ParsedAttributes Attr(AttrFactory);
     SourceLocation NoLoc;
     D.AddTypeInfo(DeclaratorChunk::getFunction(/*hasProto=*/true,
                                                /*isAmbiguous=*/false,
diff --git a/test/Parser/cxx0x-lambda-expressions.cpp b/test/Parser/cxx0x-lambda-expressions.cpp
index 289d03c223..189a6448e1 100644
--- a/test/Parser/cxx0x-lambda-expressions.cpp
+++ b/test/Parser/cxx0x-lambda-expressions.cpp
@@ -24,6 +24,7 @@ class C {
     [] () -> class C { return C(); };
     [] () -> enum E { return e; };
 
+    [] [[noreturn]] { while (1) ; }; // expected-error {{lambda requires '()' before attribute specifier}}
     [] -> int { return 0; }; // expected-error{{lambda requires '()' before return type}}
     [] mutable -> int { return 0; }; // expected-error{{lambda requires '()' before 'mutable'}}
     [](int) -> {}; // PR13652 expected-error {{expected a type}}