From 71046b4a52ce8e3e0ab86e5fe8c8ef20a4bd4538 Mon Sep 17 00:00:00 2001
From: Yaroslav Lepenkin <yaroslav.lepenkin@jetbrains.com>
Date: Tue, 4 Oct 2016 12:01:51 +0300
Subject: [PATCH] [Parameter Name Hints] show for single param null and this

---
 .../impl/ParameterNameHintsManager.java       | 16 ++++++++++++--
 .../daemon/inlays/InlayParameterHintsTest.kt  | 21 +++++++++++++++++++
 2 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/java/java-impl/src/com/intellij/codeInsight/daemon/impl/ParameterNameHintsManager.java b/java/java-impl/src/com/intellij/codeInsight/daemon/impl/ParameterNameHintsManager.java
index f308388bab40..accf64efdab0 100644
--- a/java/java-impl/src/com/intellij/codeInsight/daemon/impl/ParameterNameHintsManager.java
+++ b/java/java-impl/src/com/intellij/codeInsight/daemon/impl/ParameterNameHintsManager.java
@@ -64,20 +64,32 @@ public class ParameterNameHintsManager {
     myDescriptors = descriptors;
   }
 
-  private static boolean isMethodToShowParams(PsiCallExpression callExpression, JavaResolveResult resolveResult) {
+  private static boolean isMethodToShowParams(@NotNull PsiCallExpression callExpression, @NotNull JavaResolveResult resolveResult) {
     PsiElement element = resolveResult.getElement();
     if (element instanceof PsiMethod) {
       PsiMethod method = (PsiMethod)element;
       if (isSetter(method) || isBuilder(callExpression, method)) return false;
       if (hasSingleParameter(method)) {
         PsiParameter parameter = method.getParameterList().getParameters()[0];
-        return PsiType.VOID.equals(method.getReturnType()) || isBoolean(parameter);
+        return PsiType.VOID.equals(method.getReturnType()) || isBoolean(parameter) || isNullOrThis(callExpression);
       }
       return !isCommonMethod(method);
     }
     return false;
   }
 
+  private static boolean isNullOrThis(@NotNull PsiCallExpression callExpression) {
+    PsiExpressionList list = callExpression.getArgumentList();
+    PsiExpression[] expressions = list != null ? list.getExpressions() : null;
+    if (expressions != null && expressions.length > 0) {
+      PsiExpression expression = expressions[0];
+      if (expression.textMatches("null") || expression.textMatches("this")) {
+        return true;
+      }
+    }
+    return false;
+  }
+
   private static boolean isBuilder(PsiCallExpression expression, PsiMethod method) {
     if (expression instanceof PsiNewExpression) {
       return false;
diff --git a/java/java-tests/testSrc/com/intellij/codeInsight/daemon/inlays/InlayParameterHintsTest.kt b/java/java-tests/testSrc/com/intellij/codeInsight/daemon/inlays/InlayParameterHintsTest.kt
index 6f18a4fe58d1..e49fb2e6f845 100644
--- a/java/java-tests/testSrc/com/intellij/codeInsight/daemon/inlays/InlayParameterHintsTest.kt
+++ b/java/java-tests/testSrc/com/intellij/codeInsight/daemon/inlays/InlayParameterHintsTest.kt
@@ -526,6 +526,27 @@ public class VarArgTest {
         .assertInlays("test->this", "endIndex->1000")
   }
   
+  fun `test inline strange methods`() {
+    setup("""
+public class Test {
+  
+  void main() {
+    createContent(null);
+    createNewContent(this);
+  }
+
+  Content createContent(DockManager manager) {}
+  Content createNewContent(Test test) {}
+
+}
+interface DockManager {}
+interface Content {}
+""")
+
+    onLineStartingWith("createContent").assertInlays("manager->null")
+    onLineStartingWith("createNewContent").assertInlays("test->this")
+  }
+  
   fun `test do not inline builder pattern`() {
     setup("""
 class Builder {