KT-769, KT-773 wrong compilation of when

compiler/backend/src/org/jetbrains/jet/codegen/ExpressionCodegen.java

@@ -2562,13 +2562,21 @@ If finally block is present, its last expression is the value of try expression.
     public StackValue visitWhenExpression(JetWhenExpression expression, StackValue receiver) {
         JetExpression expr = expression.getSubjectExpression();
         final Type subjectType = expressionType(expr);
+        final Type resultType = expressionType(expression);
         final int subjectLocal = myFrameMap.enterTemp(subjectType.getSize());
         gen(expr, subjectType);
         v.store(subjectLocal, subjectType);
 
         Label end = new Label();
-        Label nextCondition = null;
         boolean hasElse = false;
+        for (JetWhenEntry whenEntry : expression.getEntries()) {
+            if(whenEntry.isElse()) {
+                hasElse = true;
+                break;
+            }
+        }
+
+        Label nextCondition = null;
         for (JetWhenEntry whenEntry : expression.getEntries()) {
             if (nextCondition != null) {
                 v.mark(nextCondition);
@@ -2588,13 +2596,13 @@ If finally block is present, its last expression is the value of try expression.
                     }
                 }
             }
-            else {
+
-                hasElse = true;
-            }
             v.visitLabel(thisEntry);
-            genToJVMStack(whenEntry.getExpression());
+            gen(whenEntry.getExpression(), resultType);
             mark.dropTo();
-            v.goTo(end);
+            if (!whenEntry.isElse()) {
+                v.goTo(end);
+            }
         }
         if (!hasElse && nextCondition != null) {
             v.mark(nextCondition);
@@ -2603,7 +2611,7 @@ If finally block is present, its last expression is the value of try expression.
         v.mark(end);
 
         myFrameMap.leaveTemp(subjectType.getSize());
-        return StackValue.onStack(expressionType(expression));
+        return StackValue.onStack(resultType);
     }
 
     private StackValue generateWhenCondition(Type subjectType, int subjectLocal, JetWhenCondition condition, @Nullable Label nextEntry) {

compiler/testData/codegen/regressions/kt769.jet

@@ -0,0 +1,11 @@
+namespace w_range
+
+fun box() : String {
+    var i = 0
+    when (i) {
+        1 => i--
+        else => { i = 2 }
+    }
+    System.out?.println(i)
+    return "OK"
+}

compiler/testData/codegen/regressions/kt773.jet

@@ -0,0 +1,25 @@
+namespace demo2
+
+fun print(o : Any?) {}
+
+fun test(i : Int) {
+    var monthString : String? = "<empty>"
+        when (i) {
+        1 => {
+            print(1)
+            print(2)
+            print(3)
+            print(4)
+            print(5)
+        }
+       else => {
+            monthString = "Invalid month"
+        }
+    }
+    print(monthString)
+}
+
+fun box() : String {
+    for (i in 1..12) test(i)
+    return "OK"
+}

compiler/tests/org/jetbrains/jet/codegen/ControlStructuresTest.java

@@ -221,6 +221,16 @@ public class ControlStructuresTest extends CodegenTestCase {
         blackBoxFile("regressions/kt434.jet");
     }
 
+    public void testKt769() throws Exception {
+        blackBoxFile("regressions/kt769.jet");
+//        System.out.println(generateToText());
+    }
+
+    public void testKt773() throws Exception {
+        blackBoxFile("regressions/kt773.jet");
+//        System.out.println(generateToText());
+    }
+
     public void testQuicksort() throws Exception {
         blackBoxFile("controlStructures/quicksort.jet");
 //        System.out.println(generateToText());