[Issue 20277] New: Template this parameters are not respected in static context

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=20277

          Issue ID: 20277
           Summary: Template this parameters are not respected in static
                    context
           Product: D
           Version: D2
          Hardware: x86_64
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P1
         Component: dmd
          Assignee: nobody at puremagic.com
          Reporter: maxsamukha at gmail.com

class A {
    void foo(this T)() {
    }

    static void bar(this T)() {
    }

    template baz(this T) {
        static void baz() {
        }
    }
}

class B : A {
}

void main()
{   
    B b; 
    b.foo(); // ok

    B.bar(); //fail
    b.bar(); // fail

    b.baz(); // ok
    B.baz(); // fail
}

onlineapp.d(22): Error: template onlineapp.A.bar cannot deduce function from
argument types !()(), candidates are:
onlineapp.d(5):        bar(this T)()
onlineapp.d(23): Error: template onlineapp.A.bar cannot deduce function from
argument types !()(), candidates are:
onlineapp.d(5):        bar(this T)()
onlineapp.d(26): Error: template onlineapp.A.baz cannot deduce function from
argument types !()(), candidates are:
onlineapp.d(8):        baz(this T)()

run.dlang.io: https://run.dlang.io/is/Hme9vp

Accessing the static type of a class in the context of a base class is an
extremely useful feature, and there is no reason to restrict it to just
non-static functions, precluding valid use cases like factory function
generation etc.

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