From 019ccae7f6671210cd41f1829a61ce93c550be4b Mon Sep 17 00:00:00 2001
From: Stepan Koltsov <stepan.koltsov@jetbrains.com>
Date: Thu, 3 Nov 2011 21:11:03 +0400
Subject: [PATCH] KT-175: infer nullability in then block from if condition

if (x != null) {
    // x is non-null here
}
---
 .../jet/lang/resolve/calls/CallResolver.java          |  2 +-
 .../types/expressions/ExpressionTypingServices.java   |  7 ++++++-
 .../quick/InferNullabilityInThenBlock.jet             | 11 +++++++++++
 3 files changed, 18 insertions(+), 2 deletions(-)
 create mode 100644 compiler/testData/checkerWithErrorTypes/quick/InferNullabilityInThenBlock.jet

diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/resolve/calls/CallResolver.java b/compiler/frontend/src/org/jetbrains/jet/lang/resolve/calls/CallResolver.java
index 5341725067d..231bf7a3e0f 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/resolve/calls/CallResolver.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/resolve/calls/CallResolver.java
@@ -652,7 +652,7 @@ public class CallResolver {
             List<JetExpression> argumentExpressions = resolvedArgument.getArgumentExpressions();
             for (JetExpression argumentExpression : argumentExpressions) {
                 ExpressionTypingServices temporaryServices = new ExpressionTypingServices(semanticServices, candidateCall.getTrace());
-                JetType type = temporaryServices.getType(scope, argumentExpression, parameterType);
+                JetType type = temporaryServices.getType(scope, argumentExpression, parameterType, dataFlowInfo);
                 if (type == null) {
                     candidateCall.argumentHasNoType();
                 }
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 13731b9f345..f47a527d75b 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
@@ -53,10 +53,15 @@ public class ExpressionTypingServices {
 
     @Nullable
     public JetType getType(@NotNull final JetScope scope, @NotNull JetExpression expression, @NotNull JetType expectedType) {
+        return getType(scope, expression, expectedType, DataFlowInfo.EMPTY);
+    }
+
+    @Nullable
+    public JetType getType(@NotNull final JetScope scope, @NotNull JetExpression expression, @NotNull JetType expectedType, DataFlowInfo dataFlowInfo) {
         ExpressionTypingContext context = ExpressionTypingContext.newContext(
                 semanticServices,
                 new HashMap<JetPattern, DataFlowInfo>(), new HashMap<JetPattern, List<VariableDescriptor>>(), new LabelResolver(),
-                trace, scope, DataFlowInfo.EMPTY, expectedType, FORBIDDEN, false
+                trace, scope, dataFlowInfo, expectedType, FORBIDDEN, false
         );
         return expressionTypingFacade.getType(expression, context);
     }
diff --git a/compiler/testData/checkerWithErrorTypes/quick/InferNullabilityInThenBlock.jet b/compiler/testData/checkerWithErrorTypes/quick/InferNullabilityInThenBlock.jet
new file mode 100644
index 00000000000..4925867c8c6
--- /dev/null
+++ b/compiler/testData/checkerWithErrorTypes/quick/InferNullabilityInThenBlock.jet
@@ -0,0 +1,11 @@
+
+fun ff(a: String) = 1
+
+fun gg() {
+    val a: String? = ""
+
+    if (a != null) {
+        ff(a)
+    }
+}
+