Bug 4217 – Function overloads are not distinguished when instantiating templates

Created attachment 639 Patch for DMD svn r496 -------------------- interface I { int test(int); real test(real); } pragma(msg, typeof(__traits(getOverloads, I, "test"))); template Test(alias func) { pragma(msg, "Test: ", typeof(func)); } alias Test!(__traits(getOverloads, I, "test")[0]) Test0; alias Test!(__traits(getOverloads, I, "test")[1]) Test1; static assert(!__traits(isSame, Test0, Test1)); -------------------- (int(int), real(real)) Test: int(int) test.d(12): Error: static assert (!true) is false -------------------- There is no "Test: real(real)" in the output. And the two aliases are reported as the same; the first instance Test0 is reused for the second instantiation (Test1). The attached patch fixes the problem by adding a check for overloaded functions to the match() function in template.c.

Created attachment 640 Patch for DMD svn r496 I've forgotten to add the essential check: f1 != f2.

Created attachment 641 Patch for DMD svn r496

Created attachment 762 Patch against dmd r680, implements FuncDeclaration::equals() Updated patch and a cleaned up test case. -------------------- test.d template Return(alias fun) { static if (is(typeof(fun) R == return)) alias R Return; } interface I { int square(int n); real square(real n); } alias Return!( __traits(getOverloads, I, "square")[0] ) R0; alias Return!( __traits(getOverloads, I, "square")[1] ) R1; static assert(! is(R0 == R1)); // (14) -------------------- % dmd -o- -c test.d test.d(14): Error: static assert (!true) is false -------------------- The problem is that template alias (symbol) parameters are matched in terms of the identifier via Dsymbol::equals(). The new patch implements FuncDeclaration::equals() that checks for function type.

Tested similar code: -------- template Seq(T...){ alias T Seq; } class A{ int f() const{ return 0; } int f() immutable{ return 0; } } alias Seq!(__traits(getOverloads, A, "f")) Overloads; template Typeof(alias a) { pragma(msg, typeof(a)); alias typeof(a) Typeof; } static assert(is(Typeof!(Overloads[0]) == typeof(Overloads[0]))); static assert(is(Typeof!(Overloads[1]) == typeof(Overloads[1]))); //should be OK -------- It is important for writing meta.algorithm against overload set.