Auto merge of #93312 - pierwill:map-all-local-trait-impls, r=cjgillot

Return an indexmap in `all_local_trait_impls` query

The data structure previously used here required that `DefId` be `Ord`. As part of #90317, we do not want `DefId` to implement `Ord`.

compiler/rustc_middle/src/ty/mod.rs

@@ -28,7 +28,7 @@ use crate::ty::subst::{GenericArg, InternalSubsts, Subst, SubstsRef};
 use crate::ty::util::Discr;
 use rustc_ast as ast;
 use rustc_attr as attr;
-use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_data_structures::tagged_ptr::CopyTaggedPtr;
 use rustc_hir as hir;
@@ -43,7 +43,6 @@ use rustc_span::{sym, Span};
 use rustc_target::abi::Align;
 
 use std::cmp::Ordering;
-use std::collections::BTreeMap;
 use std::hash::{Hash, Hasher};
 use std::ops::ControlFlow;
 use std::{fmt, ptr, str};
@@ -136,7 +135,7 @@ pub struct ResolverOutputs {
     /// via `extern crate` item and not `--extern` option or compiler built-in.
     pub extern_prelude: FxHashMap<Symbol, bool>,
     pub main_def: Option<MainDefinition>,
-    pub trait_impls: BTreeMap<DefId, Vec<LocalDefId>>,
+    pub trait_impls: FxIndexMap<DefId, Vec<LocalDefId>>,
     /// A list of proc macro LocalDefIds, written out in the order in which
     /// they are declared in the static array generated by proc_macro_harness.
     pub proc_macros: Vec<LocalDefId>,