Bug 4886 – Template (alias) tuple parameters cannot take .length property in compiletime

This code doesn't work! ---- auto test(ARGS...)() { int[ARGS.length] x; return x; } void main(string[] args) { void func(){ } auto t = test!(func)(); } ---- Results: prog.d(3): Error: identifier 'length' of 'ARGS.length' is not defined prog.d(3): Error: index is not a type or an expression prog.d(10): Error: template instance prog.main.test!(func) error instantiating Workaround is this: ---- size_t lengthof(ARGS...)() { return ARGS.length; } auto test(ARGS...)() { int[lengthof!(ARGS)()] x; return x; } void main(string[] args) { void func(){ } auto t = test!(func)(); } ----

Reduced test case: template Foo(T...) { int[T.length] x; } static assert(Foo!(1, 2, 3).x.length == 3); void main() {} A workaround: template Foo(T...) { int[cast(int)T.length] x; } static assert(Foo!(1, 2, 3).x.length == 3); void main() {}

Created attachment 764 Patch against dmd r680, fixes resolveHelper() This patch fixes the reported issue and bug 2953 (D2). It passed dmd, druntime and phobos tests. The patch also fixes the following problems: -------------------- struct R { alias int T; } struct S { R r; alias r this; } S.T x; // (10) int[S.r.offsetof] y; // (11) -------------------- % dmd -o- -c test.d test.d(10): Error: S.T is used as a type test.d(11): Error: no property 'offsetof' for type 'R'

All of cases work in 2.060head.