xref: /external/clang/test/CXX/temp/temp.fct.spec/temp.deduct/temp.deduct.call/p6.cpp

// RUN: %clang_cc1 -fsyntax-only -verify %s

namespace test0 {
  template<class T> void apply(T x, void (*f)(T)) { f(x); } // expected-note 2 {{candidate template ignored: deduced conflicting types for parameter 'T'}}\
  // expected-note {{no overload of 'temp2' matching 'void (*)(int)'}}

  template<class A> void temp(A);
  void test0() {
    // okay: deduce T=int from first argument, A=int during overload
    apply(0, &temp);
    apply(0, &temp<>);

    // okay: deduce T=int from first and second arguments
    apply(0, &temp<int>);

    // deduction failure: T=int from first, T=long from second
    apply(0, &temp<long>); // expected-error {{no matching function for call to 'apply'}}
  }

  void over(int);
  int over(long);

  void test1() {
    // okay: deductions match
    apply(0, &over);

    // deduction failure: deduced T=long from first argument, T=int from second
    apply(0L, &over); // expected-error {{no matching function for call to 'apply'}}
  }

  void over(short);

  void test2() {
    // deduce T=int from first arg, second arg is undeduced context,
    // pick correct overload of 'over' during overload resolution for 'apply'
    apply(0, &over);
  }

  template<class A, class B> B temp2(A);
  void test3() {
    // deduce T=int from first arg, A=int B=void during overload resolution
    apply(0, &temp2);
    apply(0, &temp2<>);
    apply(0, &temp2<int>);

    // overload failure
    apply(0, &temp2<long>); // expected-error {{no matching function for call to 'apply'}}
  }
}

namespace test1 {
  template<class T> void invoke(void (*f)(T)) { f(T()); } // expected-note 6 {{couldn't infer template argument}} \
  // expected-note {{candidate template ignored: couldn't infer template argument 'T'}}

  template<class T> void temp(T);
  void test0() {
    // deduction failure: overload has template => undeduced context
    invoke(&temp); // expected-error {{no matching function for call to 'invoke'}}
    invoke(&temp<>); // expected-error {{no matching function for call to 'invoke'}}

    // okay: full template-id
    invoke(&temp<int>);
  }

  void over(int);
  int over(long);

  void test1() {
    // okay: only one overload matches
    invoke(&over);
  }

  void over(short);

  void test2() {
    // deduction failure: overload has multiple matches => undeduced context
    invoke(&over); // expected-error {{no matching function for call to 'invoke'}}
  }

  template<class A, class B> B temp2(A);
  void test3() {
    // deduction failure: overload has template => undeduced context
    // (even though partial application temp2<int> could in theory
    // let us infer T=int)
    invoke(&temp2); // expected-error {{no matching function for call to 'invoke'}}
    invoke(&temp2<>); // expected-error {{no matching function for call to 'invoke'}}
    invoke(&temp2<int>); // expected-error {{no matching function for call to 'invoke'}}

    // okay: full template-id
    invoke(&temp2<int, void>);

    // overload failure
    invoke(&temp2<int, int>); // expected-error {{no matching function for call to 'invoke'}}
  }
}

namespace rdar8360106 {
  template<typename R, typename T> void f0(R (*)(T), T);
  template<typename R, typename T> void f1(R (&)(T) , T); // expected-note{{candidate template ignored: couldn't infer template argument 'R'}}
  template<typename R, typename T> void f2(R (* const&)(T), T); // expected-note{{candidate template ignored: couldn't infer template argument 'R'}}

  int g(int);
  int g(int, int);

  void h() {
    f0(g, 1);
    f0(&g, 1);
    f1(g, 1);
    f1(&g, 1); // expected-error{{no matching function for call to 'f1'}}
    f2(g, 1); // expected-error{{no matching function for call to 'f2'}}
    f2(&g, 1);
  }
}

namespace PR11713 {
  template<typename T>
  int f(int, int, int);

  template<typename T>
  float f(float, float);

  template<typename R, typename B1, typename B2, typename A1, typename A2>
  R& g(R (*)(B1, B2), A1, A2);

  void h() {
    float &fr = g(f<int>, 1, 2);
  }
}