Implement the lvalue-to-rvalue conversion where needed. The

lvalue-to-rvalue conversion adjusts lvalues of qualified, non-class
type to rvalue expressions of the unqualified variant of that
type. For example, given:

  const int i;
  (void)(i + 17);

the lvalue-to-rvalue conversion for the subexpression "i" will turn it
from an lvalue expression (a DeclRefExpr) with type 'const int' into
an rvalue expression with type 'int'. Both C and C++ mandate this
conversion, and somehow we've slid through without implementing it. 

We now have both DefaultFunctionArrayConversion and
DefaultFunctionArrayLvalueConversion, and which gets used depends on
whether we do the lvalue-to-rvalue conversion or not. Generally, we do
the lvalue-to-rvalue conversion, but there are a few notable
exceptions:
  - the left-hand side of a '.' operator
  - the left-hand side of an assignment
  - a C++ throw expression
  - a subscript expression that's subscripting a vector

Making this change exposed two issues with blocks:
  - we were deducing const-qualified return types of non-class type
  from a block return, which doesn't fit well
  - we weren't always setting the known return type of a block when it
  was provided with the ^return-type syntax

Fixes the current Clang-on-Clang compile failure and PR6076.

llvm-svn: 95167

1 files changed, 4 insertions, 0 deletions

diff --git a/clang/test/SemaCXX/enum.cpp b/clang/test/SemaCXX/enum.cpp
index 47ae06ab0e6..dc4a506dda2 100644
--- a/clang/test/SemaCXX/enum.cpp
+++ b/clang/test/SemaCXX/enum.cpp
@@ -67,3 +67,7 @@ namespace PR6061 {
     enum { id }; 
   };
 }
+
+namespace Conditional {
+  enum a { A }; a x(const enum a x) { return 1?x:A; }
+}