Centralize error reporting of improper uses of incomplete types in the
new DiagnoseIncompleteType. It provides additional information about
struct/class/union/enum types when possible, either by pointing to the
forward declaration of that type or by pointing to the definition (if
we're in the process of defining that type). 
Fixes <rdar://problem/6500531>.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@62521 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Sema/array-constraint.c b/test/Sema/array-constraint.c
index 596d19f..69475b7 100644
--- a/test/Sema/array-constraint.c
+++ b/test/Sema/array-constraint.c
@@ -1,6 +1,6 @@
 // RUN: clang -fsyntax-only -verify -pedantic %s
 
-struct s; 
+struct s;  // expected-note {{forward declaration of 'struct s'}}
 struct s* t (struct s z[]) {   // expected-error {{array has incomplete element type}}
   return z;
 }