Bug 24479 – [REG2.104] Error on getAttributes on getOverloads of templates

Testcase, https://d.godbolt.org/z/cheqP1eof: ``` import std.meta : Filter; struct S { S opBinary(string op: "-")(S rhs) const pure nothrow @nogc { return rhs; } S opBinary(string op: "*")(S dur) const pure nothrow @nogc { return dur; } } private enum hasExternalUDA(alias A) = is(A == External) || is(typeof(A) == External); void foo() { static foreach (t; __traits(getOverloads, S, "opBinary", true)) { static assert( Filter!(hasExternalUDA, __traits(getAttributes, t)).length == 0 ); } static foreach (t; __traits(getOverloads, S, "opBinary", true)) static foreach(attr; __traits(getAttributes, t)) pragma(msg, attr); static assert(__traits(getOverloads, S, "opBinary", true).length == 2); alias A = __traits(getAttributes, __traits(getOverloads, S, "opBinary", true)[1]); } ``` Fails (deprecations are errors!) since dlang 2.104, with deprecations: ``` <source>(16): Deprecation: `__traits(getAttributes)` may only be used for individual functions, not overload sets such as: `opBinary` <source>(16): the result of `__traits(getOverloads)` may be used to select the desired function to extract attributes from <source>(20): Deprecation: `__traits(getAttributes)` may only be used for individual functions, not overload sets such as: `opBinary` <source>(20): the result of `__traits(getOverloads)` may be used to select the desired function to extract attributes from <source>(24): Deprecation: `__traits(getAttributes)` may only be used for individual functions, not overload sets such as: `opBinary` <source>(24): the result of `__traits(getOverloads)` may be used to select the desired function to extract attributes from ``` Loosely related to https://issues.dlang.org/show_bug.cgi?id=23966. I don't know a workaround, because iterating with explicit indexing as suggested in 23966 also does not work (last line of testcase).

I would point out that making deprecations errors pretty much defeats their entire purpose vs just changing the code without a deprecation. They're supposed to inform you about code that you're going to need to change without immediately breaking your code. So, anyone compiling their code with -de is going to be getting errors when they're not supposed to - and it _will_ cause problems in some cases with generic code, because template constraints routinely test whether a particular piece of code compiles or not. Of course, regardless of how deprecations are treated, there then needs to be a way to transform your code appropriately so that it no longer triggers the deprecation, but deprecations are only treated as errors if you choose to do so, and it's usually a bad idea to do so.

@RazvanN7 updated dlang/dmd pull request #16358 "Fix Issue 24479 - [REG2.104] Error on getAttributes on getOverloads of templates" fixing this issue: - Fix Bugzilla Issue 24479 - [REG2.104] Error on getAttributes on getOverloads of templates https://github.com/dlang/dmd/pull/16358

dlang/dmd pull request #16358 "Fix Issue 24479 - [REG2.104] Error on getAttributes on getOverloads of templates" was merged into stable: - 2e5d85a28ce1254f443b9bcd323c8d821cb8fed8 by RazvanN7: Fix Bugzilla Issue 24479 - [REG2.104] Error on getAttributes on getOverloads of templates https://github.com/dlang/dmd/pull/16358

dlang/dmd pull request #16406 "Merge stable" was merged into master: - 9ca4c29549f944b820bbffc3e7b94c6f5ac23b1e by RazvanN7: Fix Bugzilla Issue 24479 - [REG2.104] Error on getAttributes on getOverloads of templates https://github.com/dlang/dmd/pull/16406