Improve our handling of user-defined conversions as part of overload
resolution. There are two sources of problems involving user-defined
conversions that this change eliminates, along with providing simpler
interfaces for checking implicit conversions:

  - It eliminates a case of infinite recursion found in Boost.

  - It eliminates the search for the constructor needed to copy a temporary
    generated by an implicit conversion from overload
    resolution. Overload resolution assumes that, if it gets a value
    of the parameter's class type (or a derived class thereof), there
    is a way to copy if... even if there isn't. We now model this
    properly.




git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@101680 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/SemaCXX/aggregate-initialization.cpp b/test/SemaCXX/aggregate-initialization.cpp
index 708a8f2..81a0e6f 100644
--- a/test/SemaCXX/aggregate-initialization.cpp
+++ b/test/SemaCXX/aggregate-initialization.cpp
@@ -60,10 +60,10 @@
 
 void f() {
   A as1[1] = { };
-  A as2[1] = { 1 }; // expected-error {{copying array element of type 'A' invokes deleted copy constructor}}
+  A as2[1] = { 1 }; // expected-error {{copying array element of type 'A' invokes deleted constructor}}
 
   B b1 = { };
-  B b2 = { 1 }; // expected-error {{copying member subobject of type 'A' invokes deleted copy constructor}}
+  B b2 = { 1 }; // expected-error {{copying member subobject of type 'A' invokes deleted constructor}}
   
   C c1 = { 1 };
 }
diff --git a/test/SemaCXX/conditional-expr.cpp b/test/SemaCXX/conditional-expr.cpp
index cb78a2e..aa41323 100644
--- a/test/SemaCXX/conditional-expr.cpp
+++ b/test/SemaCXX/conditional-expr.cpp
@@ -224,7 +224,7 @@
 
   struct Foo3 {
     Foo3();
-    Foo3(Foo3&);
+    Foo3(Foo3&); // expected-note{{would lose const qualifier}}
   };
 
   struct Bar {
@@ -236,7 +236,6 @@
   void f() {
     (void)(true ? Bar() : Foo1()); // okay
     (void)(true ? Bar() : Foo2()); // okay
-    // FIXME: Diagnostic below could be improved
-    (void)(true ? Bar() : Foo3()); // expected-error{{incompatible operand types ('PR6757::Bar' and 'PR6757::Foo3')}}
+    (void)(true ? Bar() : Foo3()); // expected-error{{no viable constructor copying temporary}}
   }
 }
diff --git a/test/SemaCXX/conversion-function.cpp b/test/SemaCXX/conversion-function.cpp
index 972409c..dfc0650 100644
--- a/test/SemaCXX/conversion-function.cpp
+++ b/test/SemaCXX/conversion-function.cpp
@@ -129,7 +129,7 @@
 };
 
 A1 f() {
-  return "Hello"; // expected-error{{invokes deleted copy constructor}}
+  return "Hello"; // expected-error{{invokes deleted constructor}}
 }
 
 namespace source_locations {
@@ -176,3 +176,29 @@
     *operator int();  // expected-error {{must use a typedef to declare a conversion to 'int *'}}
   };
 }
+
+namespace smart_ptr {
+  class Y { 
+    class YRef { };
+
+    Y(Y&);
+
+  public:
+    Y();
+    Y(YRef);
+
+    operator YRef(); // expected-note{{candidate function}}
+  };
+
+  struct X { // expected-note{{candidate constructor (the implicit copy constructor) not}}
+    explicit X(Y);
+  };
+
+  Y make_Y();
+
+  X f() {
+    X x = make_Y(); // expected-error{{no viable conversion from 'smart_ptr::Y' to 'smart_ptr::X'}}
+    X x2(make_Y());
+    return X(Y());
+  }
+}
diff --git a/test/SemaCXX/copy-initialization.cpp b/test/SemaCXX/copy-initialization.cpp
index e5b1fd7..ea67e6f 100644
--- a/test/SemaCXX/copy-initialization.cpp
+++ b/test/SemaCXX/copy-initialization.cpp
@@ -25,19 +25,17 @@
 namespace PR6757 {
   struct Foo {
     Foo();
-    Foo(Foo&);
+    Foo(Foo&); // expected-note{{candidate constructor not viable}}
   };
 
   struct Bar {
     operator const Foo&() const;
   };
 
-  void f(Foo); // expected-note{{candidate function not viable: no known conversion from 'PR6757::Bar' to 'PR6757::Foo' for 1st argument}}
+  void f(Foo);
 
-  // FIXME: This isn't really the right reason for the failure. We
-  // should fail after overload resolution.
   void g(Foo foo) {
-    f(Bar()); // expected-error{{no matching function for call to 'f'}}
+    f(Bar()); // expected-error{{no viable constructor copying parameter of type 'PR6757::Foo const'}}
     f(foo);
   }
 }
diff --git a/test/SemaCXX/user-defined-conversions.cpp b/test/SemaCXX/user-defined-conversions.cpp
index 4367f4b..5de7f44 100644
--- a/test/SemaCXX/user-defined-conversions.cpp
+++ b/test/SemaCXX/user-defined-conversions.cpp
@@ -67,3 +67,18 @@
   Base b4(ctd);
   Base b5 = ctfd;
 }
+
+struct X1 {
+  X1(X1&); // expected-note{{candidate constructor not viable: no known conversion from 'X1' to 'X1 &' for 1st argument}}
+};
+
+struct X2 {
+  operator X1();
+};
+
+int &f(X1);
+float &f(...);
+
+void g(X2 b) {
+  int &ir = f(b); // expected-error{{no viable constructor copying parameter of type 'X1'}}
+}
diff --git a/test/SemaTemplate/constructor-template.cpp b/test/SemaTemplate/constructor-template.cpp
index 82c2aa4..b6ca72e 100644
--- a/test/SemaTemplate/constructor-template.cpp
+++ b/test/SemaTemplate/constructor-template.cpp
@@ -94,3 +94,18 @@
 }
 
 template void default_ctor_inst<int>();
+
+template<typename T>
+struct X5 {
+  X5();
+  X5(const T &);
+};
+
+struct X6 {
+  template<typename T> X6(T);
+};
+
+void test_X5_X6() {
+  X5<X6> tf;
+  X5<X6> tf2(tf);
+}