Bug 1100 – Alias parameters don't accept primitive types.

template MyAlias(alias A) { alias A MyAlias; } void main() { alias MyAlias!(int) Myint; // This line fails: // template instance MyAlias!(int) does not match any template declaration } This disagrees with the spec (http://www.digitalmars.com/d/template.html#aliasparameters) which says that alias parameters can be type names -- I would certainly consider 'int' to be a type name. Furthermore, it's unintuitive because a similar call like this works fine: struct Int { int x; } void main() { alias MyAlias!(Int) MyInt; }

I changed "type names" to "typedef names" clarify it. The compiler works as intended - use a template type parameter to pass an arbitrary type. "int" is a keyword, not a symbol name.

I would still argue that this is unintuitive behavior; to me an alias parameter is anything that can be aliased. Allowing all types except primitive types in alias parameters creates a seemingly arbitrary distinction between primitive and user types -- don't we want to decrease these differences as much as possible? I can't think of any realistic use cases for primitive types as alias parameters. However, I also can't for userland types. PS. To be really pedantic, Int could be regarded as a symbol in the following: alias int Int; alias MyAlias!(Int) Int2; // MyAlias from before // The above alias also doesn't work

Added to DStress as http://dstress.kuehne.cn/compile/a/alias_42_A.d http://dstress.kuehne.cn/compile/a/alias_42_B.d http://dstress.kuehne.cn/nocompile/a/alias_42_C.d

(In reply to comment #3) > Added to DStress as > http://dstress.kuehne.cn/compile/a/alias_42_A.d > http://dstress.kuehne.cn/compile/a/alias_42_B.d > http://dstress.kuehne.cn/nocompile/a/alias_42_C.d > Int isn't defined in C, so even if alias parameters did accept primitive types (which there isn't *any* reason for not to), it wouldn't compile.

This was fixed.