fix(transformer/using): correctly reparent scopes in for of stmt

Author: camc314

crates/oxc_transformer/src/proposals/explicit_resource_management.rs

@@ -115,7 +115,11 @@ impl<'a> Traverse<'a> for ExplicitResourceManagement<'a, '_> {
 
         let scope_id = match &mut for_of_stmt.body {
             Statement::BlockStatement(block) => block.scope_id(),
-            _ => ctx.create_child_scope(for_of_stmt_scope_id, ScopeFlags::empty()),
+            _ => ctx.scoping.insert_scope_below_statement_from_scope_id(
+                &for_of_stmt.body,
+                for_of_stmt.scope_id(),
+                ScopeFlags::empty(),
+            ),
         };
         ctx.scoping_mut().set_symbol_scope_id(for_of_init_symbol_id, scope_id);
         ctx.scoping_mut().move_binding(for_of_stmt_scope_id, scope_id, &for_of_init_name);

crates/oxc_traverse/src/context/scoping.rs

@@ -102,6 +102,24 @@ impl TraverseScoping {
         self.insert_scope_below(&collector.scope_ids, flags)
     }
 
+    /// Insert a scope into scope tree below a statement.
+    ///
+    /// Statement must be in provided scope.
+    /// New scope is created as child of the provided scope.
+    /// All child scopes of the statement are reassigned to be children of the new scope.
+    ///
+    /// `flags` provided are amended to inherit from parent scope's flags.
+    pub fn insert_scope_below_statement_from_scope_id(
+        &mut self,
+        stmt: &Statement,
+        scope_id: ScopeId,
+        flags: ScopeFlags,
+    ) -> ScopeId {
+        let mut collector = ChildScopeCollector::new();
+        collector.visit_statement(stmt);
+        self.insert_scope_below_from_scope_id(&collector.scope_ids, scope_id, flags)
+    }
+
     /// Insert a scope into scope tree below an expression.
     ///
     /// Expression must be in current scope.
@@ -153,6 +171,28 @@ impl TraverseScoping {
         new_scope_id
     }
 
+    fn insert_scope_below_from_scope_id(
+        &mut self,
+        child_scope_ids: &[ScopeId],
+        scope_id: ScopeId,
+        flags: ScopeFlags,
+    ) -> ScopeId {
+        // Remove these scopes from parent's children
+        if self.scoping.has_scope_child_ids() {
+            self.scoping.remove_child_scopes(scope_id, child_scope_ids);
+        }
+
+        // Create new scope as child of parent
+        let new_scope_id = self.create_child_scope(scope_id, flags);
+
+        // Set scopes as children of new scope instead
+        for &child_id in child_scope_ids {
+            self.scoping.set_scope_parent_id(child_id, Some(new_scope_id));
+        }
+
+        new_scope_id
+    }
+
     /// Remove scope for an expression from the scope chain.
     ///
     /// Delete the scope and set parent of its child scopes to its parent scope.

tasks/transform_conformance/snapshots/oxc.snap.md

@@ -1,6 +1,6 @@
 commit: 578ac4df
 
-Passed: 138/229
+Passed: 139/229
 
 # All Passed:
 * babel-plugin-transform-class-static-block
@@ -320,21 +320,10 @@ x Output mismatch
 x Output mismatch
 
 
-# babel-plugin-proposal-explicit-resource-management (0/3)
+# babel-plugin-proposal-explicit-resource-management (1/3)
 * export-class-name/input.js
 x Output mismatch
 
-* for-of-no-block/input.js
-Scope children mismatch:
-after transform: ScopeId(1): [ScopeId(2), ScopeId(3), ScopeId(4), ScopeId(5), ScopeId(7)]
-rebuilt        : ScopeId(1): [ScopeId(2), ScopeId(3), ScopeId(5), ScopeId(7)]
-Scope children mismatch:
-after transform: ScopeId(4): []
-rebuilt        : ScopeId(3): [ScopeId(4)]
-Scope parent mismatch:
-after transform: ScopeId(3): Some(ScopeId(1))
-rebuilt        : ScopeId(4): Some(ScopeId(3))
-
 * function-with-scopes-in-params/input.js
 Bindings mismatch:
 after transform: ScopeId(1): ["_usingCtx", "a", "b", "x", "y"]