[PATCH] Improve diagnostic message for misplaced square brackets

[Richard Trieu]

================
Comment at: lib/Parse/ParseDecl.cpp:4841
@@ -4824,3 +4840,3 @@
     // portion is empty), if an abstract-declarator is allowed.
     D.SetIdentifier(0, Tok.getLocation());
 
----------------
Richard Smith wrote:
> This looks like it'll provide the wrong location if there were misplaced brackets.
The recovery for brackets requires !D.mayOmitIdentifier() [line 4710] while this branch requires D.mayOmitIdentifier().  Either bracket recovery happens or this code executes, but not both.

================
Comment at: lib/Parse/ParseDecl.cpp:4862
@@ -4838,3 +4861,3 @@
                                         : D.getDeclSpec().getSourceRange());
-    else if (getLangOpts().CPlusPlus) {
-      if (Tok.is(tok::period) || Tok.is(tok::arrow))
+    } else if (getLangOpts().CPlusPlus) {
+      if (!UnhandledError && (Tok.is(tok::period) || Tok.is(tok::arrow)))
----------------
Richard Smith wrote:
> Have you considered putting the bracket parsing code way down here (and recursively calling back into this function after parsing them)?
Currently, the error correction of:
  int [1] a [2];
to 
  int a[1][2];

If this was done recursively, the bracket recovery would go to the end instead to:
  int a[2][1];

http://reviews.llvm.org/D2712