diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/types/expressions/ExpressionTypingServices.java b/compiler/frontend/src/org/jetbrains/jet/lang/types/expressions/ExpressionTypingServices.java
index d91da99c2a3..17d2fc36d6e 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/types/expressions/ExpressionTypingServices.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/types/expressions/ExpressionTypingServices.java
@@ -192,7 +192,9 @@ public class ExpressionTypingServices {
         WritableScope scope = new WritableScopeImpl(
                 outerScope, containingDescriptor, new TraceBasedRedeclarationHandler(context.trace), "getBlockReturnedType");
         scope.changeLockLevel(WritableScope.LockLevel.BOTH);
-        return getBlockReturnedTypeWithWritableScope(scope, block, coercionStrategyForLastExpression, context, trace);
+        JetType r = getBlockReturnedTypeWithWritableScope(scope, block, coercionStrategyForLastExpression, context, trace);
+        scope.changeLockLevel(WritableScope.LockLevel.READING);
+        return r;
     }
 
     private Map<JetExpression, JetType> collectReturnedExpressionsWithTypes(