Reimplement reference initialization (C++ [dcl.init.ref]) using the
new notion of an "initialization sequence", which encapsulates the
computation of the initialization sequence along with diagnostic
information and the capability to turn the computed sequence into an
expression. At present, I've only switched one CheckReferenceInit
callers over to this new mechanism; more will follow.

Aside from (hopefully) being much more true to the standard, the
diagnostics provided by this reference-initialization code are a bit
better than before. Some examples:

p5-var.cpp:54:12: error: non-const lvalue reference to type 'struct
Derived'
      cannot bind to a value of unrelated type 'struct Base'
  Derived &dr2 = b; // expected-error{{non-const lvalue reference to
  ...
           ^     ~
p5-var.cpp:55:9: error: binding of reference to type 'struct Base' to
a value of
      type 'struct Base const' drops qualifiers
  Base &br3 = bc; // expected-error{{drops qualifiers}}
        ^     ~~

p5-var.cpp:57:15: error: ambiguous conversion from derived class
      'struct Diamond' to base class 'struct Base':
    struct Diamond -> struct Derived -> struct Base
    struct Diamond -> struct Derived2 -> struct Base
  Base &br5 = diamond; // expected-error{{ambiguous conversion from
      ...
              ^~~~~~~
p5-var.cpp:59:9: error: non-const lvalue reference to type 'long'
      cannot bind to
      a value of unrelated type 'int'
  long &lr = i; // expected-error{{non-const lvalue reference to type
      ...
        ^    ~

p5-var.cpp:74:9: error: non-const lvalue reference to type 'struct
Base' cannot
      bind to a temporary of type 'struct Base'
  Base &br1 = Base(); // expected-error{{non-const lvalue reference to
  ...
        ^     ~~~~~~

p5-var.cpp:102:9: error: non-const reference cannot bind to bit-field
'i'
  int & ir1 = (ib.i); // expected-error{{non-const reference cannot
  ...
        ^     ~~~~~~
p5-var.cpp:98:7: note: bit-field is declared here
  int i : 17; // expected-note{{bit-field is declared here}}
      ^






git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@90992 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/Type.cpp b/lib/AST/Type.cpp
index 70387c7..687beae 100644
--- a/lib/AST/Type.cpp
+++ b/lib/AST/Type.cpp
@@ -434,6 +434,18 @@
   return false;
 }
 
+/// \brief Determine whether this type is any of the built-in character
+/// types.
+bool Type::isAnyCharacterType() const {
+  if (const BuiltinType *BT = dyn_cast<BuiltinType>(CanonicalType))
+    return (BT->getKind() >= BuiltinType::Char_U &&
+            BT->getKind() <= BuiltinType::Char32) ||
+           (BT->getKind() >= BuiltinType::Char_S &&
+            BT->getKind() <= BuiltinType::WChar);
+  
+  return false;
+}
+
 /// isSignedIntegerType - Return true if this is an integer type that is
 /// signed, according to C99 6.2.5p4 [char, signed char, short, int, long..],
 /// an enum decl which has a signed representation, or a vector of signed