Implement C++ DR1391 (wg21.link/cwg1391)

Check for implicit conversion sequences for non-dependent function
template parameters between deduction and substitution. The idea is to accept
as many cases as possible, on the basis that substitution failure outside the
immediate context is much more common during substitution than during implicit
conversion sequence formation.

This re-commits r290808, reverted in r290811 and r291412, with a couple of
fixes for handling of explicitly-specified non-trailing template argument
packs.

llvm-svn: 291427

4 files changed, 8 insertions, 8 deletions

diff --git a/clang/test/SemaCXX/attr-mode-tmpl.cpp b/clang/test/SemaCXX/attr-mode-tmpl.cpp
index 4e1489a8a5b..d83bb398905 100644
--- a/clang/test/SemaCXX/attr-mode-tmpl.cpp
+++ b/clang/test/SemaCXX/attr-mode-tmpl.cpp
@@ -45,7 +45,7 @@ void CheckMachineMode() {
 
 // Check attributes on function parameters.
 template <class T1, class T2>
-void CheckParameters(T1 __attribute__((mode(SI)))   paramSI,     // expected-note2{{ignored: substitution failure}}
+void CheckParameters(T1 __attribute__((mode(SI)))   paramSI,     // expected-note{{ignored: substitution failure}} expected-note-re{{not viable: no known conversion from '{{.*}}' (vector of 4 '{{.*}}' values) to 'EnumType' for 2nd argument}}
                      T1 __attribute__((mode(V4DI))) paramV4DI,   // expected-warning{{deprecated}}
                      T2 __attribute__((mode(SF)))   paramSF,
                      T2 __attribute__((mode(V4DF))) paramV4DF) { // expected-warning{{deprecated}}
diff --git a/clang/test/SemaCXX/attr-noreturn.cpp b/clang/test/SemaCXX/attr-noreturn.cpp
index a8e71db7370..6edc86c43a7 100644
--- a/clang/test/SemaCXX/attr-noreturn.cpp
+++ b/clang/test/SemaCXX/attr-noreturn.cpp
@@ -244,11 +244,11 @@ namespace PR15291 {
   template <typename T>
   void qux(T) {}
 
-  // expected-note@+5 {{candidate function [with T = void (*)(int) __attribute__((noreturn))] not viable: no overload of 'baz' matching 'void (*)(int) __attribute__((noreturn))' for 1st argument}}
-  // expected-note@+4 {{candidate function [with T = void (*)(int) __attribute__((noreturn))] not viable: no overload of 'qux' matching 'void (*)(int) __attribute__((noreturn))' for 1st argument}}
-  // expected-note@+3 {{candidate function [with T = void (*)(int) __attribute__((noreturn))] not viable: no overload of 'bar' matching 'void (*)(int) __attribute__((noreturn))' for 1st argument}}
-  // expected-note@+2 {{candidate function [with T = void (*)(int)] not viable: no overload of 'bar' matching 'void (*)(int)' for 1st argument}}
-  // expected-note@+1 {{candidate function [with T = void (int)] not viable: no overload of 'bar' matching 'void (*)(int)' for 1st argument}}
+  // expected-note@+5 {{candidate function not viable: no overload of 'baz' matching 'void (*)(int) __attribute__((noreturn))' for 1st argument}}
+  // expected-note@+4 {{candidate function not viable: no overload of 'qux' matching 'void (*)(int) __attribute__((noreturn))' for 1st argument}}
+  // expected-note@+3 {{candidate function not viable: no overload of 'bar' matching 'void (*)(int) __attribute__((noreturn))' for 1st argument}}
+  // expected-note@+2 {{candidate function not viable: no overload of 'bar' matching 'void (*)(int)' for 1st argument}}
+  // expected-note@+1 {{candidate function not viable: no overload of 'bar' matching 'void (*)(int)' for 1st argument}}
   template <typename T> void accept_T(T) {}
 
   // expected-note@+1 {{candidate function not viable: no overload of 'bar' matching 'void (*)(int)' for 1st argument}}
diff --git a/clang/test/SemaCXX/overload-call.cpp b/clang/test/SemaCXX/overload-call.cpp
index 3a01bf24b31..0e3a9ee50bb 100644
--- a/clang/test/SemaCXX/overload-call.cpp
+++ b/clang/test/SemaCXX/overload-call.cpp
@@ -338,7 +338,7 @@ namespace PR5756 {
 
 // Tests the exact text used to note the candidates
 namespace test1 {
-  template <class T> void foo(T t, unsigned N); // expected-note {{candidate function [with T = int] not viable: no known conversion from 'const char [6]' to 'unsigned int' for 2nd argument}}
+  template <class T> void foo(T t, unsigned N); // expected-note {{candidate function not viable: no known conversion from 'const char [6]' to 'unsigned int' for 2nd argument}}
   void foo(int n, char N); // expected-note {{candidate function not viable: no known conversion from 'const char [6]' to 'char' for 2nd argument}} 
   void foo(int n, const char *s, int t); // expected-note {{candidate function not viable: requires 3 arguments, but 2 were provided}}
   void foo(int n, const char *s, int t, ...); // expected-note {{candidate function not viable: requires at least 3 arguments, but 2 were provided}}
diff --git a/clang/test/SemaCXX/overload-member-call.cpp b/clang/test/SemaCXX/overload-member-call.cpp
index e0f34d937f6..6e64b25d6b5 100644
--- a/clang/test/SemaCXX/overload-member-call.cpp
+++ b/clang/test/SemaCXX/overload-member-call.cpp
@@ -70,7 +70,7 @@ void test_X2(X2 *x2p, const X2 *cx2p) {
 // Tests the exact text used to note the candidates
 namespace test1 {
   class A {
-    template <class T> void foo(T t, unsigned N); // expected-note {{candidate function [with T = int] not viable: no known conversion from 'const char [6]' to 'unsigned int' for 2nd argument}}
+    template <class T> void foo(T t, unsigned N); // expected-note {{candidate function not viable: no known conversion from 'const char [6]' to 'unsigned int' for 2nd argument}}
     void foo(int n, char N); // expected-note {{candidate function not viable: no known conversion from 'const char [6]' to 'char' for 2nd argument}} 
     void foo(int n, const char *s, int t); // expected-note {{candidate function not viable: requires 3 arguments, but 2 were provided}}
     void foo(int n, const char *s, int t, ...); // expected-note {{candidate function not viable: requires at least 3 arguments, but 2 were provided}}