From 2eae3c8876cc2f6b008bd9296869860e547e08e8 Mon Sep 17 00:00:00 2001
From: peter <peter@jetbrains.com>
Date: Tue, 22 Jul 2014 12:27:43 +0200
Subject: [PATCH] contract inference: take explicit parameter notnull into
 account (IDEA-127667)

---
 .../codeInspection/dataFlow/ContractInference.java    | 11 +++++++++--
 .../ContractInferenceFromSourceTest.groovy            | 10 ++++++++++
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/ContractInference.java b/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/ContractInference.java
index 5d8c351f5cf2..a1c908837ad0 100644
--- a/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/ContractInference.java
+++ b/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/ContractInference.java
@@ -15,6 +15,7 @@
  */
 package com.intellij.codeInspection.dataFlow;
 
+import com.intellij.codeInsight.NullableNotNullManager;
 import com.intellij.codeInspection.dataFlow.MethodContract.ValueConstraint;
 import com.intellij.openapi.util.Computable;
 import com.intellij.openapi.util.Condition;
@@ -218,7 +219,7 @@ class ContractInferenceInterpreter {
   }
 
   @Nullable
-  private static MethodContract contractWithConstraint(ValueConstraint[] state,
+  private MethodContract contractWithConstraint(ValueConstraint[] state,
                                                        int parameter, ValueConstraint paramConstraint,
                                                        ValueConstraint returnValue) {
     ValueConstraint[] newState = withConstraint(state, parameter, paramConstraint);
@@ -390,12 +391,18 @@ class ContractInferenceInterpreter {
   }
 
   @Nullable
-  private static ValueConstraint[] withConstraint(ValueConstraint[] constraints, int index, ValueConstraint constraint) {
+  private ValueConstraint[] withConstraint(ValueConstraint[] constraints, int index, ValueConstraint constraint) {
+    if (constraints[index] == constraint) return constraints;
+
     ValueConstraint negated = negateConstraint(constraint);
     if (negated != constraint && constraints[index] == negated) {
       return null;
     }
 
+    if (constraint == NULL_VALUE && NullableNotNullManager.isNotNull(myMethod.getParameterList().getParameters()[index])) {
+      return null;
+    }
+
     ValueConstraint[] copy = constraints.clone();
     copy[index] = constraint;
     return copy;
diff --git a/java/java-tests/testSrc/com/intellij/codeInspection/ContractInferenceFromSourceTest.groovy b/java/java-tests/testSrc/com/intellij/codeInspection/ContractInferenceFromSourceTest.groovy
index 8656101155a3..23eac589e2db 100644
--- a/java/java-tests/testSrc/com/intellij/codeInspection/ContractInferenceFromSourceTest.groovy
+++ b/java/java-tests/testSrc/com/intellij/codeInspection/ContractInferenceFromSourceTest.groovy
@@ -272,6 +272,16 @@ class ContractInferenceFromSourceTest extends LightCodeInsightFixtureTestCase {
     assert c == ['null, _ -> false', '!null, _ -> true']
   }
 
+  public void "test take explicit parameter notnull into account"() {
+    def c = inferContracts("""
+    final Object foo(@org.jetbrains.annotations.NotNull Object bar) {
+        if (!(bar instanceof CharSequence)) return null;
+        return new String("abc");
+    }
+    """)
+    assert c == []
+  }
+
   private String inferContract(String method) {
     return assertOneElement(inferContracts(method))
   }