fix(es/compat): Make SwitchCase handler of block-scoping stateless (#7888)

**Related issue:**

 - Closes #7885

Author: kdy1

crates/swc/tests/fixture/issues-7xxx/7885/input/.swcrc

@@ -0,0 +1,19 @@
+{
+    "jsc": {
+        "parser": {
+            "syntax": "typescript",
+            "tsx": false
+        },
+        "target": "es5",
+        "loose": false,
+        "minify": {
+            "compress": false,
+            "mangle": false
+        }
+    },
+    "module": {
+        "type": "es6"
+    },
+    "minify": false,
+    "isModule": true
+}

crates/swc/tests/fixture/issues-7xxx/7885/input/1.js

@@ -0,0 +1,12 @@
+export const loopError = () => {
+    const stack: number[] = [1];
+    while (stack.shift() !== undefined) {
+        const object = 1;
+        [].map((): number => object);
+    }
+    const kind = 0;
+    switch (kind) {
+        case 0:
+            break;
+    }
+};

crates/swc/tests/fixture/issues-7xxx/7885/output/1.js

@@ -0,0 +1,17 @@
+export var loopError = function() {
+    var _loop = function() {
+        var object = 1;
+        [].map(function() {
+            return object;
+        });
+    };
+    var stack = [
+        1
+    ];
+    while(stack.shift() !== undefined)_loop();
+    var kind = 0;
+    switch(kind){
+        case 0:
+            break;
+    }
+};

crates/swc_ecma_transforms_compat/src/es2015/block_scoping/mod.rs

@@ -431,13 +431,6 @@ impl VisitMut for BlockScoping {
         self.handle_capture_of_vars(&mut node.body);
     }
 
-    fn visit_mut_while_stmt(&mut self, node: &mut WhileStmt) {
-        self.visit_mut_with_scope(ScopeKind::new_loop(), &mut node.body);
-
-        node.test.visit_mut_with(self);
-        self.handle_capture_of_vars(&mut node.body);
-    }
-
     fn visit_mut_for_in_stmt(&mut self, node: &mut ForInStmt) {
         let blockifyed = self.blockify_for_stmt_body(&mut node.body);
         let lexical_var = if let ForHead::VarDecl(decl) = &node.left {
@@ -544,6 +537,14 @@ impl VisitMut for BlockScoping {
         self.visit_mut_stmt_like(n);
     }
 
+    fn visit_mut_switch_case(&mut self, n: &mut SwitchCase) {
+        let old_vars = self.vars.take();
+
+        n.visit_mut_children_with(self);
+
+        self.vars = old_vars;
+    }
+
     fn visit_mut_var_decl(&mut self, var: &mut VarDecl) {
         let old = self.var_decl_kind;
         self.var_decl_kind = var.kind;
@@ -569,6 +570,13 @@ impl VisitMut for BlockScoping {
             }
         }
     }
+
+    fn visit_mut_while_stmt(&mut self, node: &mut WhileStmt) {
+        self.visit_mut_with_scope(ScopeKind::new_loop(), &mut node.body);
+
+        node.test.visit_mut_with(self);
+        self.handle_capture_of_vars(&mut node.body);
+    }
 }
 
 impl BlockScoping {

crates/swc_ecma_transforms_compat/src/es2015/for_of.rs

@@ -670,7 +670,7 @@ impl VisitMut for ForOf {
                         *s = self.fold_for_stmt(Some(label.clone()), stmt.take());
                     }
                     _ => {
-                        body.visit_mut_children_with(self);
+                        body.visit_mut_with(self);
                     }
                 }
             }