From a148023fad6df86a8b28cee1c5e6fbdc09d4f00d Mon Sep 17 00:00:00 2001
From: overlookmotel <557937+overlookmotel@users.noreply.github.com>
Date: Wed, 23 Oct 2024 12:57:55 +0000
Subject: [PATCH] refactor(linter): dereference IDs as soon as possible (#6821)

Style nit. Dereference `&ScopeId` to `ScopeId` (and other IDs) as early as possible. `&ScopeId` is 8 bytes, whereas `ScopeId` is 4 bytes.

In simple cases like these, compiler will optimize it anyway, but still I think it's a better pattern to dererence early. In more complicated cases, it will be better for performance, and in my opinion, it makes things clearer if vars called `scope_id` are always a `ScopeId`, not sometimes a `&ScopeId`.
---
 crates/oxc_linter/src/rules/eslint/no_unused_vars/mod.rs | 4 ++--
 crates/oxc_linter/src/rules/jest/no_mocks_import.rs      | 4 ++--
 .../rules/typescript/no_unsafe_declaration_merging.rs    | 8 ++++----
 crates/oxc_linter/src/utils/jest.rs                      | 9 ++++-----
 4 files changed, 12 insertions(+), 13 deletions(-)

diff --git a/crates/oxc_linter/src/rules/eslint/no_unused_vars/mod.rs b/crates/oxc_linter/src/rules/eslint/no_unused_vars/mod.rs
index 1782bd28d19ed..551dd5d4cea5c 100644
--- a/crates/oxc_linter/src/rules/eslint/no_unused_vars/mod.rs
+++ b/crates/oxc_linter/src/rules/eslint/no_unused_vars/mod.rs
@@ -377,8 +377,8 @@ impl Symbol<'_, '_> {
     fn is_in_declare_global(&self) -> bool {
         self.scopes()
             .ancestors(self.scope_id())
-            .filter(|scope_id| {
-                let flags = self.scopes().get_flags(*scope_id);
+            .filter(|&scope_id| {
+                let flags = self.scopes().get_flags(scope_id);
                 flags.contains(ScopeFlags::TsModuleBlock)
             })
             .any(|ambient_module_scope_id| {
diff --git a/crates/oxc_linter/src/rules/jest/no_mocks_import.rs b/crates/oxc_linter/src/rules/jest/no_mocks_import.rs
index f0889e641700f..6fc5d1fda8d7c 100644
--- a/crates/oxc_linter/src/rules/jest/no_mocks_import.rs
+++ b/crates/oxc_linter/src/rules/jest/no_mocks_import.rs
@@ -48,8 +48,8 @@ impl Rule for NoMocksImport {
             return;
         };
 
-        for reference_id in require_reference_ids {
-            let reference = ctx.symbols().get_reference(*reference_id);
+        for &reference_id in require_reference_ids {
+            let reference = ctx.symbols().get_reference(reference_id);
             let Some(parent) = ctx.nodes().parent_node(reference.node_id()) else {
                 return;
             };
diff --git a/crates/oxc_linter/src/rules/typescript/no_unsafe_declaration_merging.rs b/crates/oxc_linter/src/rules/typescript/no_unsafe_declaration_merging.rs
index 5a2059ac00d05..f59aade117314 100644
--- a/crates/oxc_linter/src/rules/typescript/no_unsafe_declaration_merging.rs
+++ b/crates/oxc_linter/src/rules/typescript/no_unsafe_declaration_merging.rs
@@ -43,9 +43,9 @@ impl Rule for NoUnsafeDeclarationMerging {
         match node.kind() {
             AstKind::Class(decl) => {
                 if let Some(ident) = decl.id.as_ref() {
-                    for (_, symbol_id) in ctx.semantic().scopes().get_bindings(node.scope_id()) {
+                    for (_, &symbol_id) in ctx.semantic().scopes().get_bindings(node.scope_id()) {
                         if let AstKind::TSInterfaceDeclaration(scope_interface) =
-                            get_symbol_kind(*symbol_id, ctx)
+                            get_symbol_kind(symbol_id, ctx)
                         {
                             check_and_diagnostic(ident, &scope_interface.id, ctx);
                         }
@@ -53,8 +53,8 @@ impl Rule for NoUnsafeDeclarationMerging {
                 }
             }
             AstKind::TSInterfaceDeclaration(decl) => {
-                for (_, symbol_id) in ctx.semantic().scopes().get_bindings(node.scope_id()) {
-                    if let AstKind::Class(scope_class) = get_symbol_kind(*symbol_id, ctx) {
+                for (_, &symbol_id) in ctx.semantic().scopes().get_bindings(node.scope_id()) {
+                    if let AstKind::Class(scope_class) = get_symbol_kind(symbol_id, ctx) {
                         if let Some(scope_class_ident) = scope_class.id.as_ref() {
                             check_and_diagnostic(&decl.id, scope_class_ident, ctx);
                         }
diff --git a/crates/oxc_linter/src/utils/jest.rs b/crates/oxc_linter/src/utils/jest.rs
index 5f4bcc3fde46a..4710c9a6476a8 100644
--- a/crates/oxc_linter/src/utils/jest.rs
+++ b/crates/oxc_linter/src/utils/jest.rs
@@ -215,11 +215,10 @@ fn collect_ids_referenced_to_import<'a, 'c>(
 
                 if matches!(import_decl.source.value.as_str(), "@jest/globals" | "vitest") {
                     let original = find_original_name(import_decl, name);
-                    let mut ret = vec![];
-                    for reference_id in reference_ids {
-                        ret.push((*reference_id, original));
-                    }
-
+                    let ret = reference_ids
+                        .iter()
+                        .map(|&reference_id| (reference_id, original))
+                        .collect::<Vec<_>>();
                     return Some(ret);
                 }
             }