4947: Replace `impls_in_trait` query with smarter use of `CrateImplDefs` r=matklad a=jonas-schievink
`impls_in_trait` was allocating a whopping ~400 MB of RAM when running analysis-stats on r-a itself.
Remove it, instead adding a query that computes a summary `CrateImplDefs` map for all transitive dependencies. This can probably still be made more efficient, but this already reduces the peak memory usage by 25% without much performance impact on analysis-stats.
**Before**:
```
Total: 34.962107188s, 2083mb allocated 2141mb resident
422mb ImplsForTraitQuery (deps)
250mb CrateDefMapQueryQuery
147mb MacroArgQuery
140mb TraitSolveQuery (deps)
68mb InferQueryQuery (deps)
62mb ImplDatumQuery (deps)
```
**After**:
```
Total: 35.261100358s, 1520mb allocated 1569mb resident
250mb CrateDefMapQueryQuery
147mb MacroArgQuery
144mb TraitSolveQuery (deps)
68mb InferQueryQuery (deps)
61mb ImplDatumQuery (deps)
45mb BodyQuery
45mb ImplDatumQuery
```
Co-authored-by: Jonas Schievink <jonasschievink@gmail.com>
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