[Issue 23941] New: [DIP1000] Overloading by scope should be allowed

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=23941

          Issue ID: 23941
           Summary: [DIP1000] Overloading by scope should be allowed
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Keywords: safe
          Severity: enhancement
          Priority: P3
         Component: dmd
          Assignee: nobody at puremagic.com
          Reporter: dlang-bugzilla at thecybershadow.net

I think this should work (with -preview=dip1000):

///////////////////////// test2.d ////////////////////////
@safe:

import std.stdio;

char[] global;

void a(char[] arr) { writeln("non-scope"); global = arr; }
void a(scope char[] arr) { writeln("scope"); }

void b(scope char[] arr)
{
    a(arr);
}

void c()
{
    char[16] arr;
    b(arr[]);
}
//////////////////////////////////////////////////////////

Currently, it complains:

test2.d(12): Error: `test2.a` called with argument types `(char[])` matches
both:
test2.d(7):     `test2.a(char[] arr)`
and:
test2.d(8):     `test2.a(scope char[] arr)`

However, when removing one of the overloads, the program only compiles with the
non-scope one, so the compiler should be able to reduce the overload set to a
single viable overload.

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