Bug 12778 – Aliasing opBinaryRight to opBinary works only in certain cases

I've discovered a "feature" today where I can simply alias opBinaryRight to opBinary and it will work. However it stops working when 'const' is involved. Observe: ----- struct Vec2 { Vec2 opBinary(string op)(Vec2 b) const if (op == "+" || op == "-" || op == "*") { mixin("return Vec2(this.x " ~ op ~ " b.x, this.y " ~ op ~ " b.y);"); } Vec2 opBinary(string op)(float s) const if (op == "+" || op == "-" || op == "*") { mixin("return Vec2(s " ~ op ~ " this.x, s " ~ op ~ " this.y);"); } alias opBinaryRight = opBinary; float x = 0, y = 0; } void main() { Vec2 vec; auto v1 = vec + 1; // ok auto v2 = 1 + vec; // ok, opBinaryRight alias works! struct S { void test1() { Vec2 v = v1 - v2; // ok } void test2() const { Vec2 v = v1 - v2; // L37: error } Vec2 v1, v2; } } ----- test.d(37): Error: overloads const pure nothrow @nogc @safe Vec2(Vec2 b) and const (Vec2 b) both match argument list for opBinary I don't know if supporting this kind of aliasing was a feature by design or by mistake. It's definitely nice to have it, but it fails in 'test2'. It should either be fully supported (rejects-valid) or fully rejected (accepts-invalid).

https://github.com/D-Programming-Language/dmd/pull/3578 (In reply to Andrej Mitrovic from comment #0) > I don't know if supporting this kind of aliasing was a feature by design or > by mistake. It's definitely nice to have it, but it fails in 'test2'. It > should either be fully supported (rejects-valid) or fully rejected > (accepts-invalid). If both x.opBinary(y) and y.opBinaryRight(x) found, and they are exactly same symbol, x.opBinary(y) should be preferred. This is consistent with current opEquals behavior - if both x.opEquals(y) and y.opEquals(x) found and they call exactly same symbol, it will be resolved to x.opEquals(y).

Commits pushed to master at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/80e3e8a2940aa835dc59f384bbb28d09534fbedb fix Issue 12778 - Aliasing opBinaryRight to opBinary works only in certain cases https://github.com/D-Programming-Language/dmd/commit/38c5c369b571c1769a9159d7d6b737fa2588fd6f Merge pull request #3578 from 9rnsr/fix12778 Issue 12778 - Aliasing opBinaryRight to opBinary works only in certain cases