fix(transformer/private-method): clear inherited strict flags (#22508)

Fixes private method transforms so scopes inherited from a transformed private method are converted back to sloppy mode when the surrounding scope is sloppy.

Previously we only cleared `StrictMode` on the private method function scope itself. That left child scopes, such as async/generator wrapper scopes, marked as strict even though the transformed output is no longer inside a class method. This caused semantic rebuild mismatches across Babel and Test262 coverage.

Nested classes are still left strict, since class bodies are always strict mode.

crates/oxc_transformer/src/es2022/class_properties/private_method.rs

@@ -1,10 +1,12 @@
 //! ES2022: Class Properties
 //! Transform of private method uses e.g. `this.#method()`.
 
+use std::cell::Cell;
+
 use oxc_allocator::TakeIn;
 use oxc_ast::ast::*;
 use oxc_ast_visit::{VisitMut, walk_mut};
-use oxc_semantic::ScopeFlags;
+use oxc_semantic::{ScopeFlags, ScopeId};
 use oxc_span::SPAN;
 
 use crate::{Helper, common::helper_loader::helper_call_expr, context::TraverseCtx};
@@ -64,16 +66,11 @@ impl<'a> ClassProperties<'a> {
         let scope_id = function.scope_id();
         let new_parent_id = ctx.current_scope_id();
         ctx.scoping_mut().change_scope_parent_id(scope_id, Some(new_parent_id));
-        let is_strict_mode = ctx.current_scope_flags().is_strict_mode();
+        let make_sloppy_mode = !ctx.current_scope_flags().is_strict_mode();
         let flags = ctx.scoping_mut().scope_flags_mut(scope_id);
         *flags -= ScopeFlags::GetAccessor | ScopeFlags::SetAccessor;
-        if !is_strict_mode {
-            // TODO: Needs to remove all child scopes' strict mode flag if child scope
-            // is inherited from this scope.
-            *flags -= ScopeFlags::StrictMode;
-        }
 
-        PrivateMethodVisitor::new(*r#static, self, ctx)
+        PrivateMethodVisitor::new(*r#static, make_sloppy_mode, self, ctx)
             .visit_function(&mut function, ScopeFlags::Function);
 
         Some(Statement::FunctionDeclaration(function))
@@ -102,6 +99,8 @@ impl<'a> ClassProperties<'a> {
 /// 2. Transform `super` expressions.
 struct PrivateMethodVisitor<'a, 'v> {
     super_converter: ClassPropertiesSuperConverter<'a, 'v>,
+    make_sloppy_mode: bool,
+    strict_scope_depth: u32,
     /// `TransCtx` object.
     ctx: &'v mut TraverseCtx<'a>,
 }
@@ -109,6 +108,7 @@ struct PrivateMethodVisitor<'a, 'v> {
 impl<'a, 'v> PrivateMethodVisitor<'a, 'v> {
     fn new(
         is_static: bool,
+        make_sloppy_mode: bool,
         class_properties: &'v mut ClassProperties<'a>,
         ctx: &'v mut TraverseCtx<'a>,
     ) -> Self {
@@ -117,7 +117,12 @@ impl<'a, 'v> PrivateMethodVisitor<'a, 'v> {
         } else {
             ClassPropertiesSuperConverterMode::PrivateMethod
         };
-        Self { super_converter: ClassPropertiesSuperConverter::new(mode, class_properties), ctx }
+        Self {
+            super_converter: ClassPropertiesSuperConverter::new(mode, class_properties),
+            make_sloppy_mode,
+            strict_scope_depth: 0,
+            ctx,
+        }
     }
 }
 
@@ -161,6 +166,7 @@ impl<'a> VisitMut<'a> for PrivateMethodVisitor<'a, '_> {
     #[inline]
     fn visit_class(&mut self, _class: &mut Class<'a>) {
         // Ignore because we don't need to transform `super` for other classes.
+        // Nested classes are strict mode, so keep their scopes' strict flags.
 
         // TODO: Actually we do need to transform `super` in:
         // 1. Class decorators
@@ -169,4 +175,23 @@ impl<'a> VisitMut<'a> for PrivateMethodVisitor<'a, '_> {
         // 4. Class property/method/accessor decorators
         //    (or does `super` in a decorator refer to inner class?)
     }
+
+    #[inline]
+    fn enter_scope(&mut self, flags: ScopeFlags, scope_id: &Cell<Option<ScopeId>>) {
+        if !self.make_sloppy_mode {
+            return;
+        }
+
+        if self.strict_scope_depth > 0 || flags.is_strict_mode() {
+            self.strict_scope_depth += 1;
+        } else {
+            *self.ctx.scoping_mut().scope_flags_mut(scope_id.get().unwrap()) -=
+                ScopeFlags::StrictMode;
+        }
+    }
+
+    #[inline]
+    fn leave_scope(&mut self) {
+        self.strict_scope_depth = self.strict_scope_depth.saturating_sub(1);
+    }
 }

tasks/coverage/snapshots/semantic_babel.snap

@@ -2,7 +2,7 @@ commit: 3d34928e
 
 semantic_babel Summary:
 AST Parsed     : 2236/2236 (100.00%)
-Positive Passed: 2035/2236 (91.01%)
+Positive Passed: 2037/2236 (91.10%)
 semantic Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/comments/decorators/decorators-after-export/input.js
 Symbol span mismatch for "C":
 after transform: SymbolId(0): Span { start: 65, end: 66 }
@@ -46,25 +46,6 @@ Bindings mismatch:
 after transform: ScopeId(0): ["Foo"]
 rebuilt        : ScopeId(0): []
 
-semantic Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/es2022/class-private-methods/async/input.js
-Scope flags mismatch:
-after transform: ScopeId(2): ScopeFlags(StrictMode | Function)
-rebuilt        : ScopeId(4): ScopeFlags(Function)
-
-semantic Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/es2022/class-private-methods/async-generator/input.js
-Scope flags mismatch:
-after transform: ScopeId(2): ScopeFlags(StrictMode | Function)
-rebuilt        : ScopeId(4): ScopeFlags(Function)
-Scope flags mismatch:
-after transform: ScopeId(3): ScopeFlags(StrictMode)
-rebuilt        : ScopeId(5): ScopeFlags(0x0)
-Scope flags mismatch:
-after transform: ScopeId(4): ScopeFlags(StrictMode)
-rebuilt        : ScopeId(6): ScopeFlags(0x0)
-Scope flags mismatch:
-after transform: ScopeId(5): ScopeFlags(StrictMode)
-rebuilt        : ScopeId(7): ScopeFlags(0x0)
-
 semantic Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/es2022/class-private-properties/await-in-private-property-in-params-of-async-arrow/input.js
 Bindings mismatch:
 after transform: ScopeId(0): ["_asyncToGenerator", "_classPrivateFieldInitSpec"]

tasks/coverage/snapshots/semantic_typescript.snap

@@ -2,7 +2,7 @@ commit: f350b523
 
 semantic_typescript Summary:
 AST Parsed     : 4773/4773 (100.00%)
-Positive Passed: 2671/4773 (55.96%)
+Positive Passed: 2677/4773 (56.09%)
 semantic Error: tasks/coverage/typescript/tests/cases/compiler/2dArrays.ts
 Symbol reference IDs mismatch for "Cell":
 after transform: SymbolId(0): [ReferenceId(1)]
@@ -19430,14 +19430,6 @@ Unresolved references mismatch:
 after transform: ["require", "undefined"]
 rebuilt        : ["B", "require", "undefined"]
 
-semantic Error: tasks/coverage/typescript/tests/cases/conformance/classes/members/privateNames/privateNameAccessorsCallExpression.ts
-Scope flags mismatch:
-after transform: ScopeId(3): ScopeFlags(StrictMode | Function)
-rebuilt        : ScopeId(6): ScopeFlags(Function)
-Scope flags mismatch:
-after transform: ScopeId(5): ScopeFlags(StrictMode | Function)
-rebuilt        : ScopeId(8): ScopeFlags(Function)
-
 semantic Error: tasks/coverage/typescript/tests/cases/conformance/classes/members/privateNames/privateNameClassExpressionLoop.ts
 Bindings mismatch:
 after transform: ScopeId(0): ["_C_brand", "_classPrivateFieldInitSpec", "_classPrivateMethodInitSpec", "_myField", "array"]
@@ -19481,48 +19473,11 @@ Symbol reference IDs mismatch for "Test":
 after transform: SymbolId(0): [ReferenceId(0)]
 rebuilt        : SymbolId(5): []
 
-semantic Error: tasks/coverage/typescript/tests/cases/conformance/classes/members/privateNames/privateNameMethodAsync.ts
-Scope flags mismatch:
-after transform: ScopeId(2): ScopeFlags(StrictMode | Function)
-rebuilt        : ScopeId(6): ScopeFlags(Function)
-Scope flags mismatch:
-after transform: ScopeId(5): ScopeFlags(StrictMode | Function)
-rebuilt        : ScopeId(9): ScopeFlags(Function)
-
-semantic Error: tasks/coverage/typescript/tests/cases/conformance/classes/members/privateNames/privateNameStaticAccessorsCallExpression.ts
-Scope flags mismatch:
-after transform: ScopeId(3): ScopeFlags(StrictMode | Function)
-rebuilt        : ScopeId(5): ScopeFlags(Function)
-Scope flags mismatch:
-after transform: ScopeId(5): ScopeFlags(StrictMode | Function)
-rebuilt        : ScopeId(7): ScopeFlags(Function)
-
 semantic Error: tasks/coverage/typescript/tests/cases/conformance/classes/members/privateNames/privateNameStaticFieldDestructuredBinding.ts
 Symbol reference IDs mismatch for "A":
 after transform: SymbolId(0): [ReferenceId(12), ReferenceId(0), ReferenceId(25), ReferenceId(28)]
 rebuilt        : SymbolId(2): [ReferenceId(3), ReferenceId(16), ReferenceId(19)]
 
-semantic Error: tasks/coverage/typescript/tests/cases/conformance/classes/members/privateNames/privateNameStaticsAndStaticMethods.ts
-Scope flags mismatch:
-after transform: ScopeId(3): ScopeFlags(StrictMode | Function)
-rebuilt        : ScopeId(5): ScopeFlags(Function)
-Scope flags mismatch:
-after transform: ScopeId(4): ScopeFlags(StrictMode | Function)
-rebuilt        : ScopeId(7): ScopeFlags(Function)
-
-semantic Error: tasks/coverage/typescript/tests/cases/conformance/classes/members/privateNames/privateNamesAndStaticMethods.ts
-Scope flags mismatch:
-after transform: ScopeId(3): ScopeFlags(StrictMode | Function)
-rebuilt        : ScopeId(5): ScopeFlags(Function)
-Scope flags mismatch:
-after transform: ScopeId(4): ScopeFlags(StrictMode | Function)
-rebuilt        : ScopeId(7): ScopeFlags(Function)
-
-semantic Error: tasks/coverage/typescript/tests/cases/conformance/classes/members/privateNames/privateNamesAssertion.ts
-Scope flags mismatch:
-after transform: ScopeId(8): ScopeFlags(StrictMode)
-rebuilt        : ScopeId(10): ScopeFlags(0x0)
-
 semantic Error: tasks/coverage/typescript/tests/cases/conformance/classes/mixinAbstractClasses.ts
 Bindings mismatch:
 after transform: ScopeId(0): ["AbstractBase", "ConcreteBase", "DerivedFromAbstract", "DerivedFromConcrete", "wasAbstract", "wasConcrete"]

tasks/transform_conformance/snapshots/babel.snap.md

@@ -1,6 +1,6 @@
 commit: 3d34928e
 
-Passed: 700/1165
+Passed: 703/1165
 
 # All Passed:
 * babel-plugin-transform-logical-assignment-operators
@@ -192,7 +192,7 @@ x Output mismatch
 x Output mismatch
 
 
-# babel-plugin-transform-class-properties (212/269)
+# babel-plugin-transform-class-properties (213/269)
 * assumption-constantSuper/complex-super-class/input.js
 x Output mismatch
 
@@ -278,14 +278,6 @@ x Output mismatch
 * private/static-infer-name/input.js
 x Output mismatch
 
-* private/static-self-method/input.js
-Scope flags mismatch:
-after transform: ScopeId(4): ScopeFlags(StrictMode | Function)
-rebuilt        : ScopeId(4): ScopeFlags(Function)
-Scope flags mismatch:
-after transform: ScopeId(6): ScopeFlags(StrictMode | Function)
-rebuilt        : ScopeId(6): ScopeFlags(Function)
-
 * private/static-shadow/input.js
 x Output mismatch
 
@@ -415,12 +407,7 @@ x Output mismatch
 x Output mismatch
 
 
-# babel-plugin-transform-private-methods (46/148)
-* accessors/tagged-template/input.js
-Scope flags mismatch:
-after transform: ScopeId(3): ScopeFlags(StrictMode | Function | Arrow)
-rebuilt        : ScopeId(4): ScopeFlags(Function | Arrow)
-
+# babel-plugin-transform-private-methods (48/148)
 * accessors-loose/basic/input.js
 x Output mismatch
 
@@ -699,11 +686,6 @@ x Output mismatch
 * static-accessors/set-only-getter/input.js
 x Output mismatch
 
-* static-accessors/tagged-template/input.js
-Scope flags mismatch:
-after transform: ScopeId(3): ScopeFlags(StrictMode | Function)
-rebuilt        : ScopeId(4): ScopeFlags(Function)
-
 * static-accessors-loose/basic/input.js
 x Output mismatch