feature: minify: remove-return-undefined: exclude nesting

lib/minify/remove-return-undefinded/index.js

@@ -1,6 +1,18 @@
 export const report = () => `Remove 'return undefined'`;
+
+export const match = () => ({
+    'return undefined': check,
+    'return void 0': check,
+});
+
 export const replace = () => ({
     'return undefined': '',
     'return void 0': '',
 });
 
+function check(vars, {parentPath}) {
+    if (!parentPath.isBlockStatement())
+        return false;
+
+    return parentPath.parentPath.isFunction();
+}

test/fixture/function-fix.js

@@ -1 +1 @@
-function hello(){}
+function hello(){}function getWorld(){if(a)return void 0;return b;}

test/fixture/function.js

@@ -1,3 +1,10 @@
 function hello() {
     return undefined;
+}
+
+function getWorld() {
+    if (a)
+        return undefined;
+
+    return b;
 }