Disambiguation of '[[':

 * In C++11, '[[' is ill-formed unless it starts an attribute-specifier. Reject
   array sizes and array indexes which begin with a lambda-expression. Recover by
   parsing the lambda as a lambda.
 * In Objective-C++11, either '[' could be the start of a message-send.
   Fully disambiguate this case: it turns out that the grammars of message-sends,
   lambdas and attributes do not actually overlap. Accept any occurrence of '[['
   where either '[' starts a message send, but reject a lambda in an array index
   just like in C++11 mode.

Implement a couple of changes to the attribute wording which occurred after our
attributes implementation landed:
 * In a function-declaration, the attributes go after the exception specification,
   not after the right paren.
 * A reference type can have attributes applied.
 * An 'identifier' in an attribute can also be a keyword. Support for alternative
   tokens (iso646 keywords) in attributes to follow.

And some bug fixes:
 * Parse attributes after declarator-ids, even if they are not simple identifiers.
 * Do not accept attributes after a parenthesized declarator.
 * Accept attributes after an array size in a new-type-id.
 * Partially disamiguate 'delete' followed by a lambda. More work is required
   here for the case where the lambda-introducer is '[]'.

llvm-svn: 154369

1 files changed, 42 insertions, 0 deletions

diff --git a/clang/test/Parser/objcxx11-attributes.mm b/clang/test/Parser/objcxx11-attributes.mm
new file mode 100644
index 0000000..719cdcc
--- /dev/null
+++ b/clang/test/Parser/objcxx11-attributes.mm
@@ -0,0 +1,42 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s
+
+@interface X {}
++ (X*) alloc;
+- (X*) init;
+- (int) getSize;
+- (void) setSize: (int) size;
+- (X*) getSelf;
+@end
+
+void f(X *noreturn) {
+  // An array size which is computed by a message send is OK.
+  int a[ [noreturn getSize] ];
+
+  // ... but is interpreted as an attribute where possible.
+  int b[ [noreturn] ]; // expected-warning {{'noreturn' only applies to function types}}
+
+  int c[ [noreturn getSize] + 1 ];
+
+  // An array size which is computed by a lambda is not OK.
+  int d[ [noreturn] { return 3; } () ]; // expected-error {{expected ']'}} expected-warning {{'noreturn' only applies}}
+
+  // A message send which contains a message send is OK.
+  [ [ X alloc ] init ];
+  [ [ int(), noreturn getSelf ] getSize ]; // expected-warning {{unused}}
+
+  // A message send which contains a lambda is OK.
+  [ [noreturn] { return noreturn; } () setSize: 4 ];
+  [ [bitand] { return noreturn; } () setSize: 5 ];
+  [[[[] { return [ X alloc ]; } () init] getSelf] getSize];
+
+  // An attribute is OK.
+  [[]];
+  [[int(), noreturn]];
+  [[class, test(foo 'x' bar),,,]];
+}
+
+template<typename...Ts> void f(Ts ...x) {
+  [[test::foo(bar, baz)...]];
+  [[used(x)...]];
+  [[x...] { return [ X alloc ]; }() init];
+}