Improve canonical_param_env_cache - #160673
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Currently it is modified with the very clunky `canonical_param_env_cache_get_or_insert` method, which takes two closures. This commit replaces that with `with_canonical_param_env_cache` a simpler accessor that is very similar to the nearby `with_global_cache`. This lets `canonicalize_param_env` use normal hash map operations. The commit also: - Introduces a dedicated `CanonicalParamEnvCache` newtype. - Adds a helpful comment to `CanonicalizeParamEnvCacheEntry::param_env`.
I now understand what is happening here.
It avoids some repetition.
There are two canonicalization steps done by `canonicalize_input` and `canonicalize_param_env`: `env` (possible cached) and `rest`. `canonicalize_param_env` does the `env` step. It returns several pieces of a canonicalizer (either from the cache or by constructing a canonicalizer) and then `canonicalize_input` uses those parts to construct a second canonicalizer, which it uses for `rest`. This commit changes things so that `canonicalize_param_env` does the `env` part (if necessary) and then returns a canonicalizer that can do the `rest` part. I find this easier to read. In particular, we no longer construct an `env` canonicalizer when it's not necessary, we immediately construct the `rest` canonicalizer.
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@bors try @rust-timer queue |
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Awaiting bors try build completion. @rustbot label: +S-waiting-on-perf |
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…, r=<try> Improve `canonical_param_env_cache`
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| Vec<CanonicalVarKind<I>>, | ||
| HashMap<I::GenericArg, usize>, | ||
| ) { | ||
| fn canonicalize_param_env(delegate: &'a D, param_env: I::ParamEnv) -> (I::ParamEnv, Self) { |
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comment on this function. its return type is kinda weird
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nit, otherwise r=me depending on perf |
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Queued c169ced with parent 88f7399, future comparison URL. |
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This function is messy and has been bothering me. Several cleanups, details in individual commits.
r? @lcnr