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.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@95167 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Sema/block-return.c b/test/Sema/block-return.c
index 6416545..2385106 100644
--- a/test/Sema/block-return.c
+++ b/test/Sema/block-return.c
@@ -109,7 +109,7 @@
 
 void foo7()
 {
- const int (^BB) (void) = ^{ const int i = 1; return i; }; // OK 
+ const int (^BB) (void) = ^{ const int i = 1; return i; }; // expected-error{{incompatible block pointer types initializing 'int (^)(void)', expected 'int const (^)(void)'}}
  const int (^CC) (void)  = ^const int{ const int i = 1; return i; }; // OK
 
   int i;
@@ -123,9 +123,8 @@
   __block const int k;
   const int cint = 100;
 
-  int (^MM) (void)  = ^{ return k; }; // expected-error {{incompatible block pointer types initializing 'int const (^)(void)', expected 'int (^)(void)'}}
-  int (^NN) (void)  = ^{ return cint; }; // expected-error {{incompatible block pointer types initializing 'int const (^)(void)', expected 'int (^)(void)'}}
-
+  int (^MM) (void)  = ^{ return k; };
+  int (^NN) (void)  = ^{ return cint; };
 }
 
 
diff --git a/test/SemaCXX/comma.cpp b/test/SemaCXX/comma.cpp
new file mode 100644
index 0000000..79ff7d1
--- /dev/null
+++ b/test/SemaCXX/comma.cpp
@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+// PR6076
+void f();
+void (&g)() = (void(), f);
+
+int a[1];
+int (&b)[1] = (void(), a);
diff --git a/test/SemaCXX/enum.cpp b/test/SemaCXX/enum.cpp
index 47ae06a..dc4a506 100644
--- a/test/SemaCXX/enum.cpp
+++ b/test/SemaCXX/enum.cpp
@@ -67,3 +67,7 @@
     enum { id }; 
   };
 }
+
+namespace Conditional {
+  enum a { A }; a x(const enum a x) { return 1?x:A; }
+}
diff --git a/test/SemaCXX/reinterpret-cast.cpp b/test/SemaCXX/reinterpret-cast.cpp
index da67560..f7ab80e 100644
--- a/test/SemaCXX/reinterpret-cast.cpp
+++ b/test/SemaCXX/reinterpret-cast.cpp
@@ -47,7 +47,7 @@
   // Invalid: T1 const* -> T2*
   (void)reinterpret_cast<int*>(icp); // expected-error {{reinterpret_cast from 'int const *' to 'int *' casts away constness}}
   // Invalid: T1*** -> T2 const* const**
-  int const *const **icpcpp = reinterpret_cast<int const* const**>(ipppc); // expected-error {{reinterpret_cast from 'int ***const' to 'int const *const **' casts away constness}}
+  int const *const **icpcpp = reinterpret_cast<int const* const**>(ipppc); // expected-error {{reinterpret_cast from 'int ***' to 'int const *const **' casts away constness}}
   // Valid: T1* -> T2*
   int *ip = reinterpret_cast<int*>(icpcpp);
   // Valid: T* -> T const*