Bug 17701 – DMD does not properly gag errors when passing `typeof` to a template inside __traits(compiles)

import std.meta: AliasSeq, staticMap; alias typesAndValues = AliasSeq!(int, false, char, "test"); //Error: found ',' when expecting '(' //Error: found ';' when expecting ')' following template argument list //Error: semicolon expected to close alias declaration assert(!__traits(compiles, { alias justTypes = staticMap!(typeof, typeAndValues); })); Tested with DMD 2.075.0. I'm not sure if this is a regression or not.

`typeof` is a keyword with specific syntax. In order for the compiler to get to the point where it runs `__traits(complies, ...)`, it has to successfully parse your code. If you violate syntax rules, as in your example, it can't successfully parse your code. This is similar to the rule that code inside inactive `version` blocks must be parseable. In order to handle cases like this, you can use string mixins: static assert(!__traits(compiles, {mixin(q{alias justTypes = ...;});}));