Improve recovery for lambda expressions that have 'mutable' or a
trailing return type but not a '()'. Recover by inserting the
parentheses. Thanks to Xeo on IRC for the example.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@150727 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/Basic/DiagnosticParseKinds.td b/include/clang/Basic/DiagnosticParseKinds.td
index dcc6f69..3960d02 100644
--- a/include/clang/Basic/DiagnosticParseKinds.td
+++ b/include/clang/Basic/DiagnosticParseKinds.td
@@ -602,6 +602,8 @@
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">;
// Availability attribute
def err_expected_version : Error<
diff --git a/lib/Parse/ParseExprCXX.cpp b/lib/Parse/ParseExprCXX.cpp
index 7185e93..d09dba2 100644
--- a/lib/Parse/ParseExprCXX.cpp
+++ b/lib/Parse/ParseExprCXX.cpp
@@ -820,7 +820,53 @@
DeclLoc, DeclEndLoc, 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.
+ Diag(Tok, diag::err_lambda_missing_parens)
+ << Tok.is(tok::arrow)
+ << FixItHint::CreateInsertion(Tok.getLocation(), "() ");
+ SourceLocation DeclLoc = Tok.getLocation();
+ SourceLocation DeclEndLoc = DeclLoc;
+
+ // Parse 'mutable', if it's there.
+ SourceLocation MutableLoc;
+ if (Tok.is(tok::kw_mutable)) {
+ MutableLoc = ConsumeToken();
+ DeclEndLoc = MutableLoc;
+ }
+
+ // Parse the return type, if there is one.
+ ParsedType TrailingReturnType;
+ if (Tok.is(tok::arrow)) {
+ SourceRange Range;
+ TrailingReturnType = ParseTrailingReturnType(Range).get();
+ if (Range.getEnd().isValid())
+ DeclEndLoc = Range.getEnd();
+ }
+
+ ParsedAttributes Attr(AttrFactory);
+ D.AddTypeInfo(DeclaratorChunk::getFunction(/*hasProto=*/true,
+ /*isVariadic=*/false,
+ /*EllipsisLoc=*/SourceLocation(),
+ /*Params=*/0, /*NumParams=*/0,
+ /*TypeQuals=*/0,
+ /*RefQualifierIsLValueRef=*/true,
+ /*RefQualifierLoc=*/SourceLocation(),
+ /*ConstQualifierLoc=*/SourceLocation(),
+ /*VolatileQualifierLoc=*/SourceLocation(),
+ MutableLoc,
+ EST_None,
+ /*ESpecLoc=*/SourceLocation(),
+ /*Exceptions=*/0,
+ /*ExceptionRanges=*/0,
+ /*NumExceptions=*/0,
+ /*NoexceptExpr=*/0,
+ DeclLoc, DeclEndLoc, D,
+ TrailingReturnType),
+ Attr, DeclEndLoc);
}
+
// FIXME: Rename BlockScope -> ClosureScope if we decide to continue using
// it.
diff --git a/test/Parser/cxx0x-lambda-expressions.cpp b/test/Parser/cxx0x-lambda-expressions.cpp
index aa2a9cf..a25116b 100644
--- a/test/Parser/cxx0x-lambda-expressions.cpp
+++ b/test/Parser/cxx0x-lambda-expressions.cpp
@@ -20,6 +20,8 @@
[&,foo] () {};
[this] () {};
+ [] -> int { return 0; }; // expected-error{{lambda requires '()' before return type}}
+ [] mutable -> int { return 0; }; // expected-error{{lambda requires '()' before 'mutable'}}
return 1;
}