fix(transformer/class-properties): make _super function outside cla…

…ss strict mode (#7708)

When create a `_super` function outside class, ensure it's always strict mode. The code it contains was previously inside the class, so was strict mode.

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

@@ -87,6 +87,7 @@
 //! Oxc output:
 //! ```js
 //! let _super = function() {
+//!   "use strict";
 //!   this.prop = foo();
 //!   return this;
 //! };
@@ -95,7 +96,7 @@
 //! }
 //! ```
 //!
-//! ESBuild does not `super()` in constructor params correctly:
+//! ESBuild does not handle `super()` in constructor params correctly:
 //! [ESBuild REPL](https://esbuild.github.io/try/#dAAwLjI0LjAALS10YXJnZXQ9ZXMyMDIwAGNsYXNzIEMgZXh0ZW5kcyBTIHsKICBwcm9wID0gZm9vKCk7CiAgY29uc3RydWN0b3IoeCA9IHN1cGVyKCksIHkgPSBzdXBlcigpKSB7fQp9Cg)
 
 use oxc_allocator::Vec as ArenaVec;
@@ -407,8 +408,20 @@ impl<'a, 'c> ConstructorParamsSuperReplacer<'a, 'c> {
         let super_func_scope_id = ctx.scopes_mut().add_scope(
             Some(outer_scope_id),
             NodeId::DUMMY,
-            ScopeFlags::Function | ScopeFlags::Arrow | ScopeFlags::StrictMode,
+            ScopeFlags::Function | ScopeFlags::StrictMode,
         );
+
+        // Add `"use strict"` directive if outer scope is not strict mode
+        let directives = if ctx.scopes().get_flags(outer_scope_id).is_strict_mode() {
+            ctx.ast.vec()
+        } else {
+            ctx.ast.vec1(ctx.ast.directive(
+                SPAN,
+                ctx.ast.string_literal(SPAN, Atom::from("use strict"), None),
+                Atom::from("use strict"),
+            ))
+        };
+
         // `return this;`
         let return_stmt = ctx.ast.statement_return(SPAN, Some(ctx.ast.expression_this(SPAN)));
         // `<inits>; return this;`
@@ -430,7 +443,7 @@ impl<'a, 'c> ConstructorParamsSuperReplacer<'a, 'c> {
                 NONE,
             ),
             NONE,
-            Some(ctx.ast.alloc_function_body(SPAN, ctx.ast.vec(), body_stmts)),
+            Some(ctx.ast.alloc_function_body(SPAN, directives, body_stmts)),
             super_func_scope_id,
         ))
     }

tasks/transform_conformance/overrides/babel-plugin-transform-class-properties/test/fixtures/public/derived-super-in-default-params-complex/output.js

@@ -1,4 +1,5 @@
 let _super = function() {
+  "use strict";
   babelHelpers.defineProperty(this, "bar", "foo");
   return this;
 };

tasks/transform_conformance/overrides/babel-plugin-transform-class-properties/test/fixtures/public/derived-super-in-default-params-in-arrow/output.js

@@ -1,4 +1,5 @@
 let _super = function() {
+  "use strict";
   babelHelpers.defineProperty(this, "bar", "foo");
   return this;
 };

tasks/transform_conformance/overrides/babel-plugin-transform-class-properties/test/fixtures/public/derived-super-in-default-params/output.js

@@ -1,4 +1,5 @@
 let _super = function() {
+  "use strict";
   babelHelpers.defineProperty(this, "bar", "foo");
   return this;
 };

tasks/transform_conformance/snapshots/babel.snap.md

@@ -822,25 +822,16 @@ x Output mismatch
 x Output mismatch
 
 * public/derived-super-in-default-params/input.js
-Scope flags mismatch:
-after transform: ScopeId(3): ScopeFlags(StrictMode | Function | Arrow)
-rebuilt        : ScopeId(1): ScopeFlags(Function)
 Symbol flags mismatch for "_super":
 after transform: SymbolId(2): SymbolFlags(FunctionScopedVariable)
 rebuilt        : SymbolId(0): SymbolFlags(BlockScopedVariable)
 
 * public/derived-super-in-default-params-complex/input.js
-Scope flags mismatch:
-after transform: ScopeId(3): ScopeFlags(StrictMode | Function | Arrow)
-rebuilt        : ScopeId(1): ScopeFlags(Function)
 Symbol flags mismatch for "_super":
 after transform: SymbolId(2): SymbolFlags(FunctionScopedVariable)
 rebuilt        : SymbolId(0): SymbolFlags(BlockScopedVariable)
 
 * public/derived-super-in-default-params-in-arrow/input.js
-Scope flags mismatch:
-after transform: ScopeId(4): ScopeFlags(StrictMode | Function | Arrow)
-rebuilt        : ScopeId(1): ScopeFlags(Function)
 Symbol flags mismatch for "_super":
 after transform: SymbolId(2): SymbolFlags(FunctionScopedVariable)
 rebuilt        : SymbolId(0): SymbolFlags(BlockScopedVariable)

tasks/transform_conformance/snapshots/oxc.snap.md

@@ -1,9 +1,8 @@
 commit: 54a8389f
 
-Passed: 94/105
+Passed: 94/106
 
 # All Passed:
-* babel-plugin-transform-class-properties
 * babel-plugin-transform-class-static-block
 * babel-plugin-transform-nullish-coalescing-operator
 * babel-plugin-transform-optional-catch-binding
@@ -16,6 +15,16 @@ Passed: 94/105
 * regexp
 
 
+# babel-plugin-transform-class-properties (1/2)
+* super-in-constructor-strict/input.js
+Symbol flags mismatch for "_super":
+after transform: SymbolId(6): SymbolFlags(FunctionScopedVariable)
+rebuilt        : SymbolId(1): SymbolFlags(BlockScopedVariable)
+Symbol flags mismatch for "_super2":
+after transform: SymbolId(7): SymbolFlags(FunctionScopedVariable)
+rebuilt        : SymbolId(5): SymbolFlags(BlockScopedVariable)
+
+
 # babel-plugin-transform-async-to-generator (14/15)
 * super/nested/input.js
 x Output mismatch

tasks/transform_conformance/tests/babel-plugin-transform-class-properties/test/fixtures/super-in-constructor-strict/input.js

@@ -0,0 +1,14 @@
+function sloppy() {
+  class C extends S {
+    prop = 1;
+    constructor(x = super()) {}
+  }
+}
+
+function strict() {
+  "use strict";
+  class C extends S {
+    prop = 1;
+    constructor(x = super()) {}
+  }
+}

tasks/transform_conformance/tests/babel-plugin-transform-class-properties/test/fixtures/super-in-constructor-strict/output.js

@@ -0,0 +1,21 @@
+function sloppy() {
+  let _super = function() {
+    "use strict";
+    babelHelpers.defineProperty(this, "prop", 1);
+    return this;
+  };
+  class C extends S {
+    constructor(x = _super.call(super())) {}
+  }
+}
+
+function strict() {
+  "use strict";
+  let _super2 = function() {
+    babelHelpers.defineProperty(this, "prop", 1);
+    return this;
+  };
+  class C extends S {
+    constructor(x = _super2.call(super())) {}
+  }
+}