fix: Replace std::HashMap with FxHashMap to fix frontend indeterminism

compiler/noirc_frontend/src/elaborator/mod.rs

@@ -1494,7 +1494,7 @@ impl<'context> Elaborator<'context> {
             traits: BTreeMap::new(),
             trait_impls: Vec::new(),
             globals: Vec::new(),
-            impls: std::collections::HashMap::new(),
+            impls: rustc_hash::FxHashMap::default(),
         };
 
         items.functions = function_sets;

compiler/noirc_frontend/src/hir/def_collector/dc_crate.rs

@@ -31,7 +31,8 @@ use crate::parser::{ParserError, SortedModule};
 use fm::FileId;
 use iter_extended::vecmap;
 use noirc_errors::{CustomDiagnostic, Span};
-use std::collections::{BTreeMap, HashMap};
+use rustc_hash::FxHashMap as HashMap;
+use std::collections::BTreeMap;
 
 use std::vec;
 
@@ -253,7 +254,7 @@ impl DefCollector {
                 types: BTreeMap::new(),
                 type_aliases: BTreeMap::new(),
                 traits: BTreeMap::new(),
-                impls: HashMap::new(),
+                impls: HashMap::default(),
                 globals: vec![],
                 trait_impls: vec![],
             },

compiler/noirc_frontend/src/hir/def_collector/dc_mod.rs

@@ -1,11 +1,12 @@
 use std::path::Path;
-use std::{collections::HashMap, vec};
+use std::vec;
 
 use acvm::{AcirField, FieldElement};
 use fm::{FileId, FileManager, FILE_EXTENSION};
 use noirc_errors::Location;
 use num_bigint::BigUint;
 use num_traits::Num;
+use rustc_hash::FxHashMap as HashMap;
 
 use crate::ast::{
     FunctionDefinition, Ident, ItemVisibility, LetStatement, ModuleDeclaration, NoirFunction,
@@ -400,7 +401,7 @@
                 self_type: None,
             };
 
-            let mut method_ids = HashMap::new();
+            let mut method_ids = HashMap::default();
             for trait_item in &trait_definition.items {
                 match trait_item {
                     TraitItem::Function {
@@ -482,7 +483,7 @@
                         }
                     }
                     TraitItem::Type { name } => {
                         // TODO(nickysn or alexvitkov): implement context.def_interner.push_empty_type_alias and get an id, instead of using TypeAliasId::dummy_id()
                         if let Err((first_def, second_def)) = self.def_collector.def_map.modules
                             [trait_id.0.local_id.0]
                             .declare_type_alias(name.clone(), TypeAliasId::dummy_id())

compiler/noirc_frontend/src/hir_def/traits.rs

@@ -1,4 +1,4 @@
-use std::collections::HashMap;
+use rustc_hash::FxHashMap as HashMap;
 
 use crate::ast::{Ident, NoirFunction};
 use crate::{