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}}
      ^

llvm-svn: 90992

1 files changed, 21 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaOverload.h b/clang/lib/Sema/SemaOverload.h
index 5eef3cebe41..3613d608834 100644
--- a/clang/lib/Sema/SemaOverload.h
+++ b/clang/lib/Sema/SemaOverload.h
@@ -15,12 +15,26 @@
 #ifndef LLVM_CLANG_SEMA_OVERLOAD_H
 #define LLVM_CLANG_SEMA_OVERLOAD_H
 
+#include "clang/AST/Decl.h"
+#include "clang/AST/Type.h"
+#include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallVector.h"
 
 namespace clang {
+  class ASTContext;
   class CXXConstructorDecl;
+  class CXXConversionDecl;
   class FunctionDecl;
 
+  /// OverloadingResult - Capture the result of performing overload
+  /// resolution.
+  enum OverloadingResult {
+    OR_Success,             ///< Overload resolution succeeded.
+    OR_No_Viable_Function,  ///< No viable function found.
+    OR_Ambiguous,           ///< Ambiguous candidates found.
+    OR_Deleted              ///< Overload resoltuion refers to a deleted function.
+  };
+    
   /// ImplicitConversionKind - The kind of implicit conversion used to
   /// convert an argument to a parameter's type. The enumerator values
   /// match with Table 9 of (C++ 13.3.3.1.1) and are listed such that
@@ -271,6 +285,7 @@ namespace clang {
   /// OverloadCandidateSet - A set of overload candidates, used in C++
   /// overload resolution (C++ 13.3).
   class OverloadCandidateSet : public llvm::SmallVector<OverloadCandidate, 16> {
+    typedef llvm::SmallVector<OverloadCandidate, 16> inherited;
     llvm::SmallPtrSet<Decl *, 16> Functions;
     
   public:
@@ -279,6 +294,12 @@ namespace clang {
     bool isNewCandidate(Decl *F) { 
       return Functions.insert(F->getCanonicalDecl()); 
     }
+
+    /// \brief Clear out all of the candidates.
+    void clear() {
+      inherited::clear();
+      Functions.clear();
+    }
   };
 } // end namespace clang