nullity: skip assert statements for local vars - should be possible to detect from usages; use in prams nullification (IDEA-60705)

java/java-impl/src/com/intellij/codeInspection/inferNullity/NullityInferrer.java

@@ -197,6 +197,10 @@ public class NullityInferrer {
       neverNull = expressionIsNeverNull(expression.getRExpression());
     }
 
+    @Override
+    public void visitAssertStatement(PsiAssertStatement statement) {
+    }
+
     @Override
     public void visitConditionalExpression(@NotNull PsiConditionalExpression expression) {
       final PsiExpression condition = expression.getCondition();
@@ -299,6 +303,10 @@ public class NullityInferrer {
       sometimesNull = expressionIsSometimesNull(expression.getRExpression());
     }
 
+    @Override
+    public void visitAssertStatement(PsiAssertStatement statement) {
+    }
+
     @Override
     public void visitConditionalExpression(@NotNull PsiConditionalExpression expression) {
       final PsiExpression condition = expression.getCondition();
@@ -534,6 +542,12 @@ public class NullityInferrer {
           opposite = lOperand;
         }
         if (opposite != null && opposite.getType() == PsiType.NULL) {
+          if (parent.getParent() instanceof PsiAssertStatement) {
+            if (((PsiBinaryExpression)parent).getOperationTokenType() == JavaTokenType.NE) {
+              registerNotNullAnnotation(parameter);
+              return true;
+            }
+          }
           registerNullableAnnotation(parameter);
           return true;
         }

java/java-tests/testData/codeInsight/nullityinferrer/afterAssertParamNotNull.java

@@ -0,0 +1,14 @@
+import org.jetbrains.annotations.NotNull;
+
+class Test {
+  @NotNull
+  public String noNull(@NotNull String text) {
+    assert text != null;
+    return "";
+  }
+
+  private void foo() {
+    @NotNull String str = "";
+    assert str != null;
+  }
+}

java/java-tests/testData/codeInsight/nullityinferrer/beforeAssertParamNotNull.java

@@ -0,0 +1,11 @@
+class Test {
+  public String noNull(String text) {
+    assert text != null;
+    return "";
+  }
+
+  private void foo() {
+    String str = "";
+    assert str != null;
+  }
+}

java/java-tests/testSrc/com/intellij/codeInsight/NullityInferrerTest.java

@@ -62,6 +62,10 @@ public class NullityInferrerTest extends CodeInsightTestCase {
     doTest(false);
   }
 
+  public void testAssertParamNotNull() throws Exception {
+    doTest(true);
+  }
+
   //-----------------------fields---------------------------------------------------
   public void testFieldsAssignment() throws Exception {
     doTest(false);