d7ee55bfd0
typeck::check_fn had an exception for the case where the tail expr was compatible with type nil -- in that case, it doesn't unify the tail expr's type with the enclosing function's result type. This seems wrong to me. There are several test cases in Issue #719 that illustrate why. If the tail expr has type T, for some type variable T that isn't resolved when this check happens, then T never gets unified with anything, which is incorrect -- T should be unified with the result type of the enclosing function. (The bug was occurring because an unconstrained type variable is compatible with type nil.) Instead, I removed the check for type nil and added a check that the function isn't an iterator -- if it's an iterator, I don't check the tail expr's type against the function result type, as that wouldn't make sense. However, this broke two test cases, and after discussion with brson, I understood that the purpose of the check was to allow semicolons to be omitted in some cases. The whole thing seems rather ad hoc. But I came up with a hacky compromise solution: instead of checking whether the tailexpr type is *compatible* with nil, we now just check whether it *is* nil. This also necessitates calling resolve_type_vars_if_possible before the check happens, which worries me. But, this fixes the bug from Issue #719 without requiring changes to any test cases. Closes #719 but I didn't try every variation -- so reopen the bug if one of the variations still doesn't work. |
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| doc | ||
| mk | ||
| src | ||
| .gitignore | ||
| AUTHORS.txt | ||
| configure | ||
| LICENSE.txt | ||
| Makefile.in | ||
| README | ||
This is a compiler and suite of associated libraries and documentation for the Rust programming language. See LICENSE.txt for terms of copyright and redistribution. See http://github.com/graydon/rust for current development page.