From 590954e9a8794e325216b9910456ecbb901682b3 Mon Sep 17 00:00:00 2001
From: Alexey Andreev <Alexey.Andreev@jetbrains.com>
Date: Tue, 23 May 2017 12:31:56 +0300
Subject: [PATCH] Add processor that removes location from ambiguous JS AST
 nodes

There are cases when it's impossible to distinguish which JS node
owns location denoted by source map. Consider example:

a + b

Both root JsBinaryNode and its arg1 point to the same start location.
Out translator provides full information, though parser can't
produce the same AST. The second AST will miss some of the locations
available on the first one. This processor gets AST node produced
by translator and removes locations from there so that both ASTs
become equal.
---
 .../utils/AmbiguousAstSourcePropagation.kt    | 79 +++++++++++++++++++
 1 file changed, 79 insertions(+)
 create mode 100644 js/js.tests/test/org/jetbrains/kotlin/js/test/utils/AmbiguousAstSourcePropagation.kt

diff --git a/js/js.tests/test/org/jetbrains/kotlin/js/test/utils/AmbiguousAstSourcePropagation.kt b/js/js.tests/test/org/jetbrains/kotlin/js/test/utils/AmbiguousAstSourcePropagation.kt
new file mode 100644
index 00000000000..9316e252089
--- /dev/null
+++ b/js/js.tests/test/org/jetbrains/kotlin/js/test/utils/AmbiguousAstSourcePropagation.kt
@@ -0,0 +1,79 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.kotlin.js.test.utils
+
+import com.intellij.psi.PsiElement
+import org.jetbrains.kotlin.js.backend.ast.*
+
+class AmbiguousAstSourcePropagation : RecursiveJsVisitor() {
+    private var sourceDefined = false
+
+    override fun visitConditional(x: JsConditional) = acceptAll(x, x.testExpression, x.thenExpression, x.elseExpression)
+    
+    override fun visitBinaryExpression(x: JsBinaryOperation) = acceptAll(x, x.arg1, x.arg2)
+
+    override fun visitPostfixOperation(x: JsPostfixOperation) = acceptAll(x, x.arg)
+
+    override fun visitArrayAccess(x: JsArrayAccess) = acceptAll(x, x.arrayExpression, x.indexExpression)
+
+    override fun visitPropertyInitializer(x: JsPropertyInitializer) = acceptAll(x, x.labelExpr, x.valueExpr)
+
+    override fun visitInvocation(invocation: JsInvocation) = acceptAll(invocation, invocation.qualifier,
+                                                                       *invocation.arguments.toTypedArray())
+
+    override fun visitNameRef(nameRef: JsNameRef) {
+        val qualifier = nameRef.qualifier
+        if (qualifier != null) {
+            acceptAll(nameRef, qualifier)
+        }
+        else {
+            super.visitNameRef(nameRef)
+        }
+    }
+
+    override fun visitElement(node: JsNode) {
+        val old = sourceDefined
+        propagate(node)
+
+        sourceDefined = false
+        super.visitElement(node)
+        sourceDefined = old
+    }
+    
+    private fun acceptAll(node: JsNode, first: JsNode, vararg remaining: JsNode) {
+        val old = sourceDefined
+        propagate(node)
+        
+        accept(first)
+
+        sourceDefined = false
+        remaining.forEach { accept(it) }
+        sourceDefined = old
+    }
+
+    private fun propagate(node: JsNode) {
+        if (!sourceDefined) {
+            val source = node.source
+            if (source is JsLocation || source is PsiElement) {
+                sourceDefined = true
+            }
+        }
+        else if (node !is JsExpressionStatement) {
+            node.source = null
+        }
+    }
+}
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