[Bug c++/101811] New: Error not helpful for misplaced 'template'

[tobi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101811

            Bug ID: 101811
           Summary: Error not helpful for misplaced 'template'
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: tobi at gcc dot gnu.org
  Target Milestone: ---

This is a bad error message that caught my eye while refactoring some code
(https://godbolt.org/z/558vM4Wb3):

struct X {
    void f();
};

template<int i>  // this line should not be here
void X::f()
{}

gives:


<source>:6:6: error: no declaration matches 'void X::f()'
    6 | void X::f()
      |      ^
<source>:2:10: note: candidate is: 'void X::f()'
    2 |     void f();
      |          ^
<source>:1:8: note: 'struct X' defined here
    1 | struct X {
      |        ^

Note that the error message doesn't actually include what's wrong and so it is
fairly confusing until you actually look at the code.