Fix KT-12173 (Kotlin Lint False Positive for "Toast created but not shown" inside SAM adapter).

(cherry picked from commit 4940d3b)

plugins/lint/lint-api/src/com/android/tools/klint/client/api/UastLintUtils.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2010-2016 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 com.android.tools.klint.client.api;
+
+import com.android.annotations.NonNull;
+import org.jetbrains.uast.*;
+
+public class UastLintUtils {
+
+    public static boolean isChildOfExpression(
+            @NonNull UExpression child,
+            @NonNull UExpression parent) {
+        UElement current = child;
+        while (current != null) {
+            if (current.equals(parent)) {
+                return true;
+            } else if (!(current instanceof UExpression)) {
+                return false;
+            }
+
+            current = current.getParent();
+        }
+
+        return false;
+    }
+    
+}

plugins/lint/lint-checks/src/com/android/tools/klint/checks/ToastDetector.java

@@ -17,6 +17,7 @@
 package com.android.tools.klint.checks;
 
 import com.android.annotations.NonNull;
+import com.android.tools.klint.client.api.UastLintUtils;
 import com.android.tools.klint.detector.api.Category;
 import com.android.tools.klint.detector.api.Context;
 import com.android.tools.klint.detector.api.Detector;
@@ -124,7 +125,7 @@ public class ToastDetector extends Detector implements UastScanner {
 
         @Override
         public boolean visitCallExpression(@NotNull UCallExpression node) {
-            if (node == mTarget) {
+            if (node.equals(mTarget)) {
                 mSeenTarget = true;
             } else if (mSeenTarget && node.matchesFunctionName("show")) { //$NON-NLS-1$
                 // TODO: Do more flow analysis to see whether we're really calling show
@@ -132,7 +133,7 @@ public class ToastDetector extends Detector implements UastScanner {
                 mFound = true;
             }
 
-            return true;
+            return super.visitCallExpression(node);
         }
 
         @Override
@@ -141,16 +142,16 @@ public class ToastDetector extends Detector implements UastScanner {
                 mSeenTarget = true;
             }
 
-            return false;
+            return super.visitQualifiedExpression(node);
         }
 
         @Override
         public boolean visitReturnExpression(@NotNull UReturnExpression node) {
-            if (mTarget.equals(node.getReturnExpression())) {
+            if (UastLintUtils.isChildOfExpression(mTarget, node.getReturnExpression())) {
                 mFound = true;
             }
 
-            return false;
+            return super.visitReturnExpression(node);
         }
 
         boolean isShowCalled() {

plugins/uast-kotlin/testData/lint/toast.kt

@@ -10,6 +10,23 @@ class ToastTest(context: Context) : Activity() {
         // Don't warn here
         return Toast.makeText(context, "foo", Toast.LENGTH_LONG)
     }
+    
+    private fun insideRunnable(context: Context) {
+        Runnable {
+            Toast.makeText(context, "foo", Toast.LENGTH_LONG).show()
+        }
+
+        Runnable {
+            val toast = Toast.makeText(context, "foo", Toast.LENGTH_LONG)
+            if (5 > 3) {
+                toast.show()
+            }
+        }
+
+        Runnable {
+            Toast.<warning descr="Toast created but not shown: did you forget to call `show()` ?">makeText(context, "foo", Toast.LENGTH_LONG)</warning>
+        }
+    }
 
     private fun showToast(context: Context) {
         // Don't warn here