Merge remote branch 'origin/master'

compiler/backend/src/org/jetbrains/jet/codegen/intrinsics/Concat.java

@@ -18,7 +18,7 @@ public class Concat implements IntrinsicMethod {
         codegen.generateStringBuilderConstructor();
         if (receiver == null) {                                    // LHS.plus(RHS)
             v.swap();                                                              // StringBuilder LHS
-            codegen.invokeAppendMethod(codegen.expressionType(arguments.get(0)));  // StringBuilder(LHS)
+            codegen.invokeAppendMethod(expectedType);  // StringBuilder(LHS)
             codegen.invokeAppend(arguments.get(0));
         }
         else {                                                     // LHS + RHS

compiler/testData/codegen/regressions/kt446.jet

@@ -0,0 +1,5 @@
+fun box(): String {
+    var s = "s"
+    s += 1
+    return if (s == "s1") "OK" else "fail"
+}

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

@@ -4,6 +4,7 @@ import java.lang.reflect.Method;
 
 /**
  * @author yole
+ * @author alex.tkachman
  */
 public class PrimitiveTypesTest extends CodegenTestCase {
     public void testPlus() throws Exception {
@@ -274,4 +275,8 @@ public class PrimitiveTypesTest extends CodegenTestCase {
     public void testKt248 () throws Exception {
         blackBoxFile("regressions/kt248.jet");
     }
+
+    public void testKt446 () throws Exception {
+        blackBoxFile("regressions/kt446.jet");
+    }
 }