Fix various soundness bugs in HRTB / method resolution #19617
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nikomatsakis
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…hen constructing generics, so that we don't add unnecessary region parameters. 2. Correct the DeBruijn indices when substituting the self type into the method signature. Previously, the DeBruijn index for the self type was not being adjusted to account for the fn binder. This mean that when late-bound regions were instantiated, you sometimes wind up with two distinct lifetimes. Fixes rust-lang#19537.
The current behavior leads to adjustments like `&&*` being applied instead of just `&` (when the unmodified receiver is a `&T` or an `&mut T`). This causes both safety errors and unexpected behavior. The safety errors result from regionck not being prepared for auto-ref-ref-like adjustments; this is worth fixing on its own, but I think the best way to do it is to modify regionck to use expr-use-visitor (and fix expr-use-visitor as well, which I don't think properly invokes `borrow` for each level of auto-ref), and for now it's simpler to just not produce the adjustment in question. (I have a separate patch porting regionck to use exprusevisitor for a different bug, so that is coming.)
…as masked by these bugs.
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Dec 12, 2014
**First commit.** Patch up debruijn indices. Fixes #19537. **Second commit.** Stop reborrowing so much. Fixes #19147. Fixes #19261. r? @nick29581
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First commit. Patch up debruijn indices. Fixes #19537.
Second commit. Stop reborrowing so much. Fixes #19147. Fixes #19261.
r? @nick29581