feat(transformer/class-properties): transform super member expressions that are inside static prop initializer (#7815)

This PR support for transforming `super.prop` to  `babelHelpers.superPropGet(_B, "prop", _B)`

Input:
```js
class A {
  static prop = 1;
}

class B extends A {
  static prop = 2;
  static propA = super.prop;
  static getPropA = () => super.prop;
}
```

Output:
```js
var _B;
class A {}
babelHelpers.defineProperty(A, "prop", 1);
class B extends A {}
_B = B;
babelHelpers.defineProperty(B, "prop", 2);
babelHelpers.defineProperty(B, "propA", babelHelpers.superPropGet(_B, "prop", _B));
babelHelpers.defineProperty(B, "getPropA", () => babelHelpers.superPropGet(_B, "prop", _B));
```

crates/oxc_transformer/src/common/helper_loader.rs

@@ -158,6 +158,7 @@ pub enum Helper {
     ToSetter,
     ClassPrivateFieldLooseKey,
     ClassPrivateFieldLooseBase,
+    SuperPropGet,
 }
 
 impl Helper {
@@ -181,6 +182,7 @@ impl Helper {
             Self::ToSetter => "toSetter",
             Self::ClassPrivateFieldLooseKey => "classPrivateFieldLooseKey",
             Self::ClassPrivateFieldLooseBase => "classPrivateFieldLooseBase",
+            Self::SuperPropGet => "superPropGet",
         }
     }
 }

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

@@ -132,6 +132,7 @@
 //! * `private_props.rs`:     Structures storing details of private properties.
 //! * `static_prop_init.rs`:  Transform of static property initializers.
 //! * `class_bindings.rs`:    Structure containing bindings for class name and temp var.
+//! * `super.rs`:             Transform `super` expressions.
 //! * `utils.rs`:             Utility functions.
 //!
 //! ## References
@@ -159,6 +160,7 @@ mod constructor;
 mod private;
 mod private_props;
 mod static_prop_init;
+mod supers;
 mod utils;
 use class_bindings::ClassBindings;
 use private_props::PrivatePropsStack;

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

@@ -200,6 +200,14 @@ impl<'a, 'ctx, 'v> VisitMut<'a> for StaticInitializerVisitor<'a, 'ctx, 'v> {
                     }
                 }
             }
+            // `super.prop`
+            Expression::StaticMemberExpression(_) => {
+                self.class_properties.transform_static_member_expression(expr, self.ctx);
+            }
+            // `super[prop]`
+            Expression::ComputedMemberExpression(_) => {
+                self.class_properties.transform_computed_member_expression(expr, self.ctx);
+            }
             // `object.#prop`
             Expression::PrivateFieldExpression(_) => {
                 self.class_properties.transform_private_field_expression(expr, self.ctx);
@@ -453,7 +461,7 @@ impl<'a, 'ctx, 'v> StaticInitializerVisitor<'a, 'ctx, 'v> {
 }
 
 impl<'a, 'ctx> ClassProperties<'a, 'ctx> {
-    fn get_temp_binding(&mut self, ctx: &mut TraverseCtx<'a>) -> &BoundIdentifier<'a> {
+    pub(super) fn get_temp_binding(&mut self, ctx: &mut TraverseCtx<'a>) -> &BoundIdentifier<'a> {
         // `PrivateProps` is the source of truth for bindings if class has private props
         // because other visitors which transform private fields may create a temp binding
         // and store it on `PrivateProps`

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

@@ -0,0 +1,86 @@
+//! ES2022: Class Properties
+//! Transform of `super` expressions.
+
+use oxc_ast::ast::*;
+use oxc_traverse::TraverseCtx;
+
+use crate::Helper;
+
+use super::ClassProperties;
+
+impl<'a, 'ctx> ClassProperties<'a, 'ctx> {
+    /// Transform static member expression where object is `super`.
+    ///
+    /// `super.prop` -> `_superPropGet(_Class, "prop", _Class)`
+    //
+    // `#[inline]` so that compiler sees that `expr` is an `Expression::StaticMemberExpression`.
+    #[inline]
+    pub(super) fn transform_static_member_expression(
+        &mut self,
+        expr: &mut Expression<'a>,
+        ctx: &mut TraverseCtx<'a>,
+    ) {
+        let Expression::StaticMemberExpression(member) = expr else { unreachable!() };
+        if matches!(member.object, Expression::Super(_)) {
+            *expr = self.transform_static_member_expression_impl(member, ctx);
+        }
+    }
+
+    fn transform_static_member_expression_impl(
+        &mut self,
+        member: &mut StaticMemberExpression<'a>,
+        ctx: &mut TraverseCtx<'a>,
+    ) -> Expression<'a> {
+        let property = &member.property;
+        let property = ctx.ast.expression_string_literal(
+            property.span,
+            property.name.clone(),
+            Some(property.name.clone()),
+        );
+        self.create_super_prop_get(member.span, property, ctx)
+    }
+
+    /// Transform computed member expression where object is `super`.
+    ///
+    /// `super[prop]` -> `_superPropGet(_Class, prop, _Class)`
+    //
+    // `#[inline]` so that compiler sees that `expr` is an `Expression::ComputedMemberExpression`.
+    #[inline]
+    pub(super) fn transform_computed_member_expression(
+        &mut self,
+        expr: &mut Expression<'a>,
+        ctx: &mut TraverseCtx<'a>,
+    ) {
+        let Expression::ComputedMemberExpression(member) = expr else { unreachable!() };
+        if matches!(member.object, Expression::Super(_)) {
+            *expr = self.transform_computed_member_expression_impl(member, ctx);
+        }
+    }
+
+    fn transform_computed_member_expression_impl(
+        &mut self,
+        member: &mut ComputedMemberExpression<'a>,
+        ctx: &mut TraverseCtx<'a>,
+    ) -> Expression<'a> {
+        let property = ctx.ast.move_expression(&mut member.expression);
+        self.create_super_prop_get(member.span, property, ctx)
+    }
+
+    /// `_superPropGet(_Class, prop, _Class)`
+    fn create_super_prop_get(
+        &mut self,
+        span: Span,
+        property: Expression<'a>,
+        ctx: &mut TraverseCtx<'a>,
+    ) -> Expression<'a> {
+        let class_binding = self.get_temp_binding(ctx);
+        // `(_Class, prop, _Class)`
+        let arguments = ctx.ast.vec_from_array([
+            Argument::from(class_binding.create_read_expression(ctx)),
+            Argument::from(property),
+            Argument::from(class_binding.create_read_expression(ctx)),
+        ]);
+        // `_superPropGet(_Class, prop, _Class)`
+        self.ctx.helper_call_expr(Helper::SuperPropGet, span, arguments, ctx)
+    }
+}

tasks/transform_conformance/snapshots/babel.snap.md

@@ -1,6 +1,6 @@
 commit: 54a8389f
 
-Passed: 562/927
+Passed: 564/927
 
 # All Passed:
 * babel-plugin-transform-class-static-block
@@ -276,7 +276,7 @@ x Output mismatch
 x Output mismatch
 
 
-# babel-plugin-transform-class-properties (176/264)
+# babel-plugin-transform-class-properties (178/264)
 * assumption-constantSuper/complex-super-class/input.js
 x Output mismatch
 
@@ -341,9 +341,6 @@ rebuilt        : ScopeId(9): Some(ScopeId(8))
 * assumption-setPublicClassFields/static-infer-name/input.js
 x Output mismatch
 
-* assumption-setPublicClassFields/static-super/input.js
-x Output mismatch
-
 * assumption-setPublicClassFields/static-super-loose/input.js
 x Output mismatch
 
@@ -645,9 +642,6 @@ rebuilt        : ScopeId(9): Some(ScopeId(8))
 * public/static-infer-name/input.js
 x Output mismatch
 
-* public/static-super/input.js
-x Output mismatch
-
 * public/super-with-collision/input.js
 x Output mismatch
 
@@ -713,7 +707,15 @@ x Output mismatch
 x Output mismatch
 
 * regression/6154/input.js
-x Output mismatch
+Scope children mismatch:
+after transform: ScopeId(3): [ScopeId(4), ScopeId(6)]
+rebuilt        : ScopeId(3): [ScopeId(4)]
+Scope children mismatch:
+after transform: ScopeId(6): []
+rebuilt        : ScopeId(4): [ScopeId(5)]
+Scope parent mismatch:
+after transform: ScopeId(4): Some(ScopeId(3))
+rebuilt        : ScopeId(5): Some(ScopeId(4))
 
 * regression/7951/input.mjs
 x Output mismatch

tasks/transform_conformance/snapshots/babel_exec.snap.md

@@ -2,7 +2,7 @@ commit: 54a8389f
 
 node: v22.12.0
 
-Passed: 186 of 215 (86.51%)
+Passed: 189 of 215 (87.91%)
 
 Failures:
 
@@ -13,9 +13,6 @@ Failures:
 AssertionError: expected '_Class' to be 'Foo' // Object.is equality
     at ./tasks/transform_conformance/fixtures/babel/babel-plugin-transform-class-properties-test-fixtures-assumption-setPublicClassFields-static-infer-name-exec.test.js:8:19
 
-./fixtures/babel/babel-plugin-transform-class-properties-test-fixtures-assumption-setPublicClassFields-static-super-exec.test.js
-Invalid access to super
-
 ./fixtures/babel/babel-plugin-transform-class-properties-test-fixtures-nested-class-super-call-in-decorator-exec.test.js
 AssertionError: expected undefined to be 'hello' // Object.is equality
     at ./tasks/transform_conformance/fixtures/babel/babel-plugin-transform-class-properties-test-fixtures-nested-class-super-call-in-decorator-exec.test.js:21:28
@@ -98,22 +95,17 @@ AssertionError: expected [Function] to throw error including '@@toPrimitive must
     at ./tasks/transform_conformance/fixtures/babel/babel-plugin-transform-class-properties-test-fixtures-public-computed-toPrimitive-exec.test.js:37:5
 
 ./fixtures/babel/babel-plugin-transform-class-properties-test-fixtures-public-delete-super-property-exec.test.js
-Invalid access to super
+AssertionError: expected function to throw an error, but it didn't
+    at ./tasks/transform_conformance/fixtures/babel/babel-plugin-transform-class-properties-test-fixtures-public-delete-super-property-exec.test.js:25:5
 
 ./fixtures/babel/babel-plugin-transform-class-properties-test-fixtures-public-loose-static-infer-name-exec.test.js
 AssertionError: expected '_Class' to be 'Foo' // Object.is equality
     at ./tasks/transform_conformance/fixtures/babel/babel-plugin-transform-class-properties-test-fixtures-public-loose-static-infer-name-exec.test.js:8:19
 
-./fixtures/babel/babel-plugin-transform-class-properties-test-fixtures-public-loose-static-super-exec.test.js
-Invalid access to super
-
 ./fixtures/babel/babel-plugin-transform-class-properties-test-fixtures-public-static-infer-name-exec.test.js
 AssertionError: expected '_Class' to be 'Foo' // Object.is equality
     at ./tasks/transform_conformance/fixtures/babel/babel-plugin-transform-class-properties-test-fixtures-public-static-infer-name-exec.test.js:9:19
 
-./fixtures/babel/babel-plugin-transform-class-properties-test-fixtures-public-static-super-exec.test.js
-Invalid access to super
-
 ./fixtures/babel/babel-plugin-transform-optional-chaining-test-fixtures-assumption-noDocumentAll-parenthesized-expression-member-call-exec.test.js
 TypeError: Cannot read properties of undefined (reading 'x')
     at m (./tasks/transform_conformance/fixtures/babel/babel-plugin-transform-optional-chaining-test-fixtures-assumption-noDocumentAll-parenthesized-expression-member-call-exec.test.js:10:16)