[Bug c++/57678] New: too many errors for bad template parameter

[manu at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57678

            Bug ID: 57678
           Summary: too many errors for bad template parameter
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: manu at gcc dot gnu.org

template<int N> int foo(int a) { return N; }

void bar(void)
{
    foo<x>(5);
}


triggers:

test.cpp:5:9: error: ‘x’ was not declared in this scope
     foo<x>(5);
         ^
test.cpp:5:13: error: no matching function for call to ‘foo(int)’
     foo<x>(5);
             ^
test.cpp:5:13: note: candidate is:
test.cpp:1:21: note: template<int N> int foo(int)
 template<int N> int foo(int a) { return N; }
                     ^
test.cpp:1:21: note:   template argument deduction/substitution failed:
test.cpp:5:13: error: template argument 1 is invalid
     foo<x>(5);
             ^

The second error is not useful (and the last "error" should be a note), why
even try to match the function call if the template argument was invalid?

Is there any case where the template argument is invalid and the invalidity is
not triggered by a previous error?

Clang:

test.cpp:5:9: error: use of undeclared identifier 'x'
    foo<x>(5);
        ^