Incorrect dependent template name error

[llvmbot]

Bugzilla Link	17401
Version	3.3
OS	All
Reporter	LLVM Bugzilla Contributor
CC	@DougGregor

Extended Description

In the code shown below, Clang claims that the call to foo within C::baz() is template-dependent and therefore must be prefixed with the template keyword. I'm not a standards expert, but it does not appear to me to be template-dependent -- the call clearly always resolves to A::foo(). Moreover, if the type of C::b is changed to B* and the call becomes b->bar().foo<T>() then no error is reported, which seems pretty suspicious.

Tested on Clang 3.2 (Ubuntu) and Clang 3.3 (Xcode 5).

G++ (4.7, 4.8) does not report an error on this code.

$ cat test.c++

class A {
public:
  template <typename T>
  T foo();
};

class B {
public:
  A bar();
};

template <typename T>
class C {
public:
  T baz() {
    return b.bar().foo<T>();
  }
  
private:
  B b;
};

$ clang++ -c test.c++
test.c++:16:20: error: use 'template' keyword to treat 'foo' as a dependent template name
    return b.bar().foo<T>();
                   ^
                   template 
1 error generated.
$

[llvmbot]

I experienced a similar problem.
See
https://stackoverflow.com/questions/44817183/is-template-qualifier-required-in-class-template-non-dependent-member-variables

[steveire]

*** Bug llvm/llvm-bugzilla-archive#38299 has been marked as a duplicate of this bug. ***

[steveire]

mentioned in issue llvm/llvm-bugzilla-archive#38299

[steveire]

mentioned in issue llvm/llvm-bugzilla-archive#39047

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: None (llvmbot)

| | | | --- | --- | | Bugzilla Link | [17401](https://llvm.org/bz17401) | | Version | 3.3 | | OS | All | | Reporter | LLVM Bugzilla Contributor | | CC | @DougGregor |

Extended Description

In the code shown below, Clang claims that the call to foo within C::baz() is template-dependent and therefore must be prefixed with the template keyword. I'm not a standards expert, but it does not appear to me to be template-dependent -- the call clearly always resolves to A::foo(). Moreover, if the type of C::b is changed to B* and the call becomes b->bar().foo<T>() then no error is reported, which seems pretty suspicious.

Tested on Clang 3.2 (Ubuntu) and Clang 3.3 (Xcode 5).

G++ (4.7, 4.8) does not report an error on this code.

$ cat test.c++

class A {
public:
  template <typename T>
  T foo();
};

class B {
public:
  A bar();
};

template <typename T>
class C {
public:
  T baz() {
    return b.bar().foo<T>();
  }
  
private:
  B b;
};

$ clang++ -c test.c++
test.c++:16:20: error: use 'template' keyword to treat 'foo' as a dependent template name
    return b.bar().foo<T>();
                   ^
                   template 
1 error generated.
$

[shafik]

Related bug: #37647

[shafik]

Looks fixed in clang10: https://godbolt.org/z/E91qMzf14