Partial body resolve: more efficient handling if-statements

idea/ide-common/src/org/jetbrains/jet/lang/resolve/lazy/PartialBodyResolveFilter.kt

@@ -208,7 +208,6 @@ class PartialBodyResolveFilter(elementToResolve: JetElement, private val body: J
         return result
     }
 
-    //TODO: more precise analysis
     private fun collectAlwaysExitPoints(expression: JetExpression?): Collection<JetExpression> {
         val result = ArrayList<JetExpression>()
         expression?.accept(object : ControlFlowVisitor() {
@@ -222,6 +221,23 @@ class PartialBodyResolveFilter(elementToResolve: JetElement, private val body: J
                 result.add(expression)
             }
 
+            override fun visitIfExpression(expression: JetIfExpression) {
+                expression.getCondition().accept(this)
+
+                val thenBranch = expression.getThen()
+                val elseBranch = expression.getElse()
+                if (thenBranch != null && elseBranch != null) { // if we have only one branch it makes no sense to search exits in it
+                    val thenExits = collectAlwaysExitPoints(thenBranch)
+                    if (thenExits.isNotEmpty()) {
+                        val elseExits = collectAlwaysExitPoints(elseBranch)
+                        if (elseExits.isNotEmpty()) {
+                            result.addAll(thenExits)
+                            result.addAll(elseExits)
+                        }
+                    }
+                }
+            }
+
             override fun visitForExpression(loop: JetForExpression) {
                 loop.getLoopRange()?.accept(this)
                 // do not make sense to search exits inside for as not necessary enter it at all

idea/testData/resolve/partialBodyResolve/IfNullConditionalReturn.dump

@@ -0,0 +1,3 @@
+Resolve target: val x: kotlin.Any?
+Skipped statements:
+if (x == null) { print(1) if (f()) return }

idea/testData/resolve/partialBodyResolve/IfNullConditionalReturn.kt

@@ -0,0 +1,13 @@
+fun foo() {
+    for (i in 1..10) {
+        val x = take()
+        if (x == null) {
+            print(1)
+            if (f()) return
+        }
+        <caret>x.hashCode()
+    }
+}
+
+fun take(): Any? = null
+fun f(): Boolean{}

idea/testData/resolve/partialBodyResolve/IfNullConditionalReturnWithElse.dump

@@ -0,0 +1,3 @@
+Resolve target: val x: kotlin.Any?
+Skipped statements:
+if (x == null) { print(1) if (f()) { return } else { print(2) } }

idea/testData/resolve/partialBodyResolve/IfNullConditionalReturnWithElse.kt

@@ -0,0 +1,18 @@
+fun foo() {
+    for (i in 1..10) {
+        val x = take()
+        if (x == null) {
+            print(1)
+            if (f()) {
+                return
+            }
+            else {
+                print(2)
+            }
+        }
+        <caret>x.hashCode()
+    }
+}
+
+fun take(): Any? = null
+fun f(): Boolean{}

idea/tests/org/jetbrains/jet/resolve/PartialBodyResolveTestGenerated.java

@@ -19,7 +19,6 @@ package org.jetbrains.jet.resolve;
 import com.intellij.testFramework.TestDataPath;
 import org.jetbrains.jet.JUnit3RunnerWithInners;
 import org.jetbrains.jet.JetTestUtils;
-import org.jetbrains.jet.test.InnerTestClasses;
 import org.jetbrains.jet.test.TestMetadata;
 import org.junit.runner.RunWith;
 
@@ -126,6 +125,18 @@ public class PartialBodyResolveTestGenerated extends AbstractPartialBodyResolveT
         doTest(fileName);
     }
 
+    @TestMetadata("IfNullConditionalReturn.kt")
+    public void testIfNullConditionalReturn() throws Exception {
+        String fileName = JetTestUtils.navigationMetadata("idea/testData/resolve/partialBodyResolve/IfNullConditionalReturn.kt");
+        doTest(fileName);
+    }
+
+    @TestMetadata("IfNullConditionalReturnWithElse.kt")
+    public void testIfNullConditionalReturnWithElse() throws Exception {
+        String fileName = JetTestUtils.navigationMetadata("idea/testData/resolve/partialBodyResolve/IfNullConditionalReturnWithElse.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("IfNullContinue.kt")
     public void testIfNullContinue() throws Exception {
         String fileName = JetTestUtils.navigationMetadata("idea/testData/resolve/partialBodyResolve/IfNullContinue.kt");