Bug 20831 – __traits(getAttributes) failes to compile when used on a parameter with no name

With dmd v2.091.1, this code fails to compile (it doesn't even print fail in the pragma, it just doesn't compile): ---------------------------------------- void foo(int f, float, @("test") string s = "test") {} static if(is(typeof(foo) Params == __parameters)) pragma(msg, __traits(getAttributes, Params[1..2])); else pragma(msg, "fail"); ---------------------------------------- But moving the code to a function makes it work somehow: ---------------------------------------- void foo(int f, float, @("test") string s = "test") {} void main() { static if(is(typeof(foo) Params == __parameters)) pragma(msg, __traits(getAttributes, Params[1..2])); else pragma(msg, "fail"); } ---------------------------------------- The 2nd version correctly prints "tuple()". In the 1st non-working version, naming the 2nd parameter also makes the problem go away.

I simplified the test a little more and see it changes based on order: ``` void main() { static if(is(typeof(foo) Params == __parameters)) pragma(msg, __traits(getAttributes, Params[0..1])); } void foo(float) {} ``` That triggers it. Now move the definition of `foo` up above main: ``` void foo(float) {} void main() { static if(is(typeof(foo) Params == __parameters)) pragma(msg, __traits(getAttributes, Params[0..1])); } ``` that works correctly. Looks like one of those semantic is not called at the right time bugs.

@BorisCarvajal created dlang/dmd pull request #11284 "Fix Issue 20831 - __traits(getAttributes) failes to compile when used…" fixing this issue: - Fix Issue 20831 - __traits(getAttributes) failes to compile when used on a parameter with no name https://github.com/dlang/dmd/pull/11284

dlang/dmd pull request #11284 "Fix Issue 20831 - __traits(getAttributes) failes to compile when used…" was merged into master: - a5d42258a8ac5e331ad3490273ceff956eb00283 by Boris Carvajal: Fix Issue 20831 - __traits(getAttributes) failes to compile when used on a parameter with no name https://github.com/dlang/dmd/pull/11284