From: Manish Goregaokar <manishsmail@gmail.com>
Date: Sat, 24 Feb 2018 23:52:07 +0000 (-0800)
Subject: Rollup merge of #48296 - ishitatsuyuki:exp-unblow, r=nikomatsakis
X-Git-Url: https://git.lizzy.rs/?a=commitdiff_plain;h=58af0c7b648dd8ccf1f1d4277ccf4d804ed4a996;p=rust.git

Rollup merge of #48296 - ishitatsuyuki:exp-unblow, r=nikomatsakis

Fix exponential projection complexity on nested types

This implements solution 1 from https://github.com/rust-lang/rust/issues/38528#issuecomment-366263076.

The code quality is currently extremely poor, but we can improve them during review.

Blocking issues:

- we probably don't want a quadratic deduplication for obligations.
- is there an alternative to deduplication?

Based on #48315.

Needs changelog. Noticable improvement on compile time is expected.

Fix #38528
Close #39684
Close #43757
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58af0c7b648dd8ccf1f1d4277ccf4d804ed4a996