Issue 9620 - Error messages of failed pure enforcement

[yebblies]

Print name of failing function, not enclosing function.

https://d.puremagic.com/issues/show_bug.cgi?id=9620

[9rnsr]

diag9620.main.bar is not a pure function, so this error message sounds weird to me.

[yebblies]

Doesn't being nested inside a pure function make it pure?

[9rnsr]

No, currently bar is not marked as pure_. And *currently_ all of local functions (both static and nested) don't inherit pure attribute from enclosing function.

I think this is a bug in Expression::checkPurity(Scope *sc, FuncDeclaration *f). Even the static local function bar has no closest pure parent, but main is incorrectly detected for that.

[yebblies]

Ok, but this just changes 'D main' cannot call impure function 'diag9620.foo' to 'diag9620.main.bar' cannot call impure function 'diag9620.foo', which at least an improvement for non-static nested functions.

[yebblies]

I removed the 'static' on the nested function. If the nested functions aren't (weakly) pure, how can they be called from a pure function and what should we call them?