Merge pull request #3526 from loganfsmyth/fix-switch-error

Fix an issue with the switch handing from PR #3490.

packages/babel-plugin-transform-es2015-block-scoping/src/index.js

@@ -435,16 +435,15 @@ class BlockScoping {
     let params = values(outsideRefs);
     let args   = values(outsideRefs);
 
-    // build the closure that we're going to wrap the block with
-    let fn = t.functionExpression(null, params, t.blockStatement(block.body));
+    const isSwitch = this.blockPath.isSwitchStatement();
+
+    // build the closure that we're going to wrap the block with, possible wrapping switch(){}
+    let fn = t.functionExpression(null, params, t.blockStatement(isSwitch ? [block] : block.body));
     fn.shadow = true;
 
     // continuation
     this.addContinuations(fn);
 
-    // replace the current block body with the one we're going to build
-    block.body = this.body;
-
     let ref = fn;
 
     if (this.loop) {
@@ -473,6 +472,10 @@ class BlockScoping {
     }
 
     this.buildClosure(ret, call);
+
+    // replace the current block body with the one we're going to build
+    if (isSwitch) this.blockPath.replaceWithMultiple(this.body);
+    else block.body = this.body;
   }
 
   /**

packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/switch-callbacks/actual.js

@@ -0,0 +1,10 @@
+function fn() {
+    switch (true) {
+    default:
+        let foo = 4;
+        if (true) {
+            let bar = () => foo;
+            console.log(bar());
+        }
+    }
+}

packages/babel-plugin-transform-es2015-block-scoping/test/fixtures/general/switch-callbacks/expected.js

@@ -0,0 +1,14 @@
+function fn() {
+    (function () {
+        switch (true) {
+            default:
+                var foo = 4;
+                if (true) {
+                    var bar = function () {
+                        return foo;
+                    };
+                    console.log(bar());
+                }
+        }
+    })();
+}