p6.cpp revision a933319ebf754396623165f9dc0a29c2a48879f5 
1// RUN: %clang_cc1 -fsyntax-only -verify %s
2
3namespace test0 {
4  template<class T> void apply(T x, void (*f)(T)) { f(x); } // expected-note 2 {{candidate template ignored: deduced conflicting types for parameter 'T'}}\
5  // expected-note {{no overload of 'temp2' matching 'void (*)(int)'}}
6
7  template<class A> void temp(A);
8  void test0() {
9    // okay: deduce T=int from first argument, A=int during overload
10    apply(0, &temp);
11    apply(0, &temp<>);
12
13    // okay: deduce T=int from first and second arguments
14    apply(0, &temp<int>);
15
16    // deduction failure: T=int from first, T=long from second
17    apply(0, &temp<long>); // expected-error {{no matching function for call to 'apply'}}
18  }
19
20  void over(int);
21  int over(long);
22
23  void test1() {
24    // okay: deductions match
25    apply(0, &over);
26
27    // deduction failure: deduced T=long from first argument, T=int from second
28    apply(0L, &over); // expected-error {{no matching function for call to 'apply'}}
29  }
30
31  void over(short);
32
33  void test2() {
34    // deduce T=int from first arg, second arg is undeduced context,
35    // pick correct overload of 'over' during overload resolution for 'apply'
36    apply(0, &over);
37  }
38
39  template<class A, class B> B temp2(A);
40  void test3() {
41    // deduce T=int from first arg, A=int B=void during overload resolution
42    apply(0, &temp2);
43    apply(0, &temp2<>);
44    apply(0, &temp2<int>);
45
46    // overload failure
47    apply(0, &temp2<long>); // expected-error {{no matching function for call to 'apply'}}
48  }
49}
50
51namespace test1 {
52  template<class T> void invoke(void (*f)(T)) { f(T()); } // expected-note 6 {{couldn't infer template argument}} \
53  // expected-note {{failed template argument deduction}}
54
55  template<class T> void temp(T);
56  void test0() {
57    // deduction failure: overload has template => undeduced context
58    invoke(&temp); // expected-error {{no matching function for call to 'invoke'}}
59    invoke(&temp<>); // expected-error {{no matching function for call to 'invoke'}}
60
61    // okay: full template-id
62    invoke(&temp<int>);
63  }
64
65  void over(int);
66  int over(long);
67
68  void test1() {
69    // okay: only one overload matches
70    invoke(&over);
71  }
72
73  void over(short);
74
75  void test2() {
76    // deduction failure: overload has multiple matches => undeduced context
77    invoke(&over); // expected-error {{no matching function for call to 'invoke'}}
78  }
79
80  template<class A, class B> B temp2(A);
81  void test3() {
82    // deduction failure: overload has template => undeduced context
83    // (even though partial application temp2<int> could in theory
84    // let us infer T=int)
85    invoke(&temp2); // expected-error {{no matching function for call to 'invoke'}}
86    invoke(&temp2<>); // expected-error {{no matching function for call to 'invoke'}}
87    invoke(&temp2<int>); // expected-error {{no matching function for call to 'invoke'}}
88
89    // okay: full template-id
90    invoke(&temp2<int, void>);
91
92    // overload failure
93    invoke(&temp2<int, int>); // expected-error {{no matching function for call to 'invoke'}}
94  }
95}
96