Auto merge of rust-lang#17610 - regexident:impl-all_in_module, r=Veykril

Add method `Impl::all_in_module(…)` for allowing more localized querying

This PR is motivated by an [outside use](https://github.com/regexident/cargo-modules) of the `ra_ap_hir` crate that would benefit from being able to more efficiently query for all impls of a given module (instead of having to query for its parent crate's impls and then filtering on `impl_hir.module(db) == module_hir`).

I have the suspicion that the code as is won't quite work for file-level modules, since those don't have a block, afaict, but with all the crate-rename and version shenanigans around the `ra_ap_` release process I haven't yet been able to figure out how to patch a `ra_ap_` dependency from a third-party crate (let alone how to test this from inside of `rust-analyzer`), so haven't been able to actually run and test this. 😔

Any hints on how to make this (i.e. the code itself, as well as the testing) work are more than welcome!

Author: bors

src/tools/rust-analyzer/crates/hir/src/lib.rs

@@ -3724,6 +3724,10 @@ impl Impl {
         inherent.all_impls().chain(trait_.all_impls()).map(Self::from).collect()
     }
 
+    pub fn all_in_module(db: &dyn HirDatabase, module: Module) -> Vec<Impl> {
+        module.id.def_map(db.upcast())[module.id.local_id].scope.impls().map(Into::into).collect()
+    }
+
     pub fn all_for_type(db: &dyn HirDatabase, Type { ty, env }: Type) -> Vec<Impl> {
         let def_crates = match method_resolution::def_crates(db, &ty, env.krate) {
             Some(def_crates) => def_crates,