Merge pull request #3171 from babel/inference-recursion

Inference recursion

packages/babel-core/test/fixtures/plugins/inference-recursion/exec.js

@@ -0,0 +1,57 @@
+var code = (function() {
+  var kind;
+  function readObj() {
+    expect('{');
+    if (!skip('}')) {
+      do {
+        expect('String');
+        expect(':');
+        readVal();
+      } while (skip(','));
+      expect('}');
+    }
+  }
+
+  function expect(str) {
+    if (kind === str) {
+      return lex();
+    }
+    throw syntaxError('Expected ' + str + ' but got ' + string.slice(start, end) + '.');
+  }
+
+  function readArr() {
+    expect('[');
+    if (!skip(']')) {
+      do {
+        readVal();
+      } while (skip(','));
+      expect(']');
+    }
+  }
+
+  function readVal() {
+    switch (kind) {
+      case '[':
+        return readArr();
+      case '{':
+        return readObj();
+      case 'String':
+        return lex();
+      default:
+        return expect('Value');
+    }
+  }
+}).toString().split('\n').slice(1, -1).join('\n');
+
+transform(code, {
+  plugins: function (b) {
+    var t = b.types;
+    return {
+      visitor: {
+        BinaryExpression: function(path) {
+          path.get("left").baseTypeStrictlyMatches(path.get("right"));
+        }
+      }
+    }
+  }
+});

packages/babel-traverse/src/path/introspection.js

@@ -235,7 +235,9 @@ export function _guessExecutionStatusRelativeTo(target) {
   let targetFuncParent = target.scope.getFunctionParent();
   let selfFuncParent = this.scope.getFunctionParent();
 
-  if (targetFuncParent !== selfFuncParent) {
+  // here we check the `node` equality as sometimes we may have different paths for the
+  // same node due to path thrashing
+  if (targetFuncParent.node !== selfFuncParent.node) {
     let status = this._guessExecutionStatusRelativeToDifferentFunctions(targetFuncParent);
     if (status) {
       return status;