perf(linter/typescript/no-this-alias): narrow AST dispatch (#28360)

Start from direct this expressions while preserving destructuring
options, allowed names, and wrapper behavior. Reduce fixture callbacks
from 13,590 to 4,350.


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Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

crates/oxc_linter/src/generated/rule_runner_impls.rs

@@ -1881,10 +1881,8 @@ impl RuleRunner for crate::rules::typescript::no_restricted_types::NoRestrictedT
 }
 
 impl RuleRunner for crate::rules::typescript::no_this_alias::NoThisAlias {
-    const NODE_TYPES: Option<&AstTypesBitset> = Some(&AstTypesBitset::from_types(&[
-        AstType::AssignmentExpression,
-        AstType::VariableDeclarator,
-    ]));
+    const NODE_TYPES: Option<&AstTypesBitset> =
+        Some(&AstTypesBitset::from_types(&[AstType::ThisExpression]));
     const RUN_FUNCTIONS: RuleRunFunctionsImplemented = RuleRunFunctionsImplemented::Run;
 }
 

crates/oxc_linter/src/rules/typescript/no_this_alias.rs

@@ -1,6 +1,6 @@
 use oxc_ast::{
     AstKind,
-    ast::{AssignmentTarget, BindingPattern, Expression, match_simple_assignment_target},
+    ast::{AssignmentTarget, BindingPattern, match_simple_assignment_target},
 };
 use oxc_diagnostics::OxcDiagnostic;
 use oxc_macros::declare_oxc_lint;
@@ -108,11 +108,12 @@ impl Rule for NoThisAlias {
     }
 
     fn run<'a>(&self, node: &AstNode<'a>, ctx: &LintContext<'a>) {
-        match node.kind() {
+        let AstKind::ThisExpression(this) = node.kind() else { return };
+        match ctx.nodes().parent_kind(node.id()) {
             AstKind::VariableDeclarator(decl) => {
                 let Some(init) = &decl.init else { return };
 
-                if !rhs_is_this_reference(init) {
+                if init.span() != this.span {
                     return;
                 }
 
@@ -132,7 +133,7 @@ impl Rule for NoThisAlias {
                 ctx.diagnostic(no_this_destructure_diagnostic(decl.id.span()));
             }
             AstKind::AssignmentExpression(assignment) => {
-                if !rhs_is_this_reference(&assignment.right) {
+                if assignment.right.span() != this.span {
                     return;
                 }
                 match &assignment.left {
@@ -171,16 +172,18 @@ impl Rule for NoThisAlias {
     }
 }
 
-#[inline]
-fn rhs_is_this_reference(rhs_expression: &Expression) -> bool {
-    matches!(rhs_expression, Expression::ThisExpression(_))
-}
-
 #[test]
 fn test() {
     use crate::tester::Tester;
 
     let pass = vec![
+        ("const self = (this);", None),
+        ("const self = this as Foo;", None),
+        ("this.value = other;", None),
+        ("this.self = this;", None),
+        ("const self = [this];", None),
+        ("function f(value = this) {}", None),
+        ("({value} = this);", None),
         // allow destructuring
         (
             "const { props, state } = this;",
@@ -201,6 +204,7 @@ fn test() {
 
     let fail = vec![
         ("const self = this;", None),
+        ("let self; self ||= this;", None),
         (
             "const { props, state } = this;",
             Some(serde_json::json!([{ "allowDestructuring": false }])),

crates/oxc_linter/src/snapshots/typescript_no_this_alias.snap

@@ -9,6 +9,13 @@ source: crates/oxc_linter/src/tester.rs
    ╰────
   help: Assigning a variable to this instead of properly using arrow lambdas may be a symptom of pre-ES2015 practices or not managing scope well.
 
+  ⚠ typescript(no-this-alias): Unexpected aliasing of 'this' to local variable.
+   ╭─[no_this_alias.tsx:1:11]
+ 1 │ let self; self ||= this;
+   ·           ────
+   ╰────
+  help: Assigning a variable to this instead of properly using arrow lambdas may be a symptom of pre-ES2015 practices or not managing scope well.
+
   ⚠ typescript(no-this-alias): Unexpected aliasing of members of 'this' to local variables.
    ╭─[no_this_alias.tsx:1:7]
  1 │ const { props, state } = this;

tasks/track_linter_timings/linter_timings.snap

@@ -493,7 +493,7 @@ typescript/no-non-null-asserted-nullish-coalescing      |   7341
 typescript/no-non-null-asserted-optional-chain          |    577
 typescript/no-non-null-assertion                        |    577
 typescript/no-require-imports                           |  62608
-typescript/no-this-alias                                |  13590
+typescript/no-this-alias                                |   4350
 typescript/no-unnecessary-parameter-property-assignment |   1916
 typescript/no-unnecessary-type-constraint               |    362
 typescript/no-unsafe-declaration-merging                |    500