From 989faff56f0d94b1fb9d66a8e962e9f8e4077d89 Mon Sep 17 00:00:00 2001
From: Hoan Nguyen <nguyenanhhoan@gmail.com>
Date: Fri, 10 May 2024 00:39:41 -0700
Subject: [PATCH] Fix bug in `InstanceOfPatternMatch` getting the variable name
 from the name of a nested class (#291)

Co-authored-by: Hoan Nguyen <hoanamzn@amazon.com>
---
 .../InstanceOfPatternMatch.java               |  4 +--
 .../InstanceOfPatternMatchTest.java           | 35 +++++++++++++++++++
 2 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/src/main/java/org/openrewrite/staticanalysis/InstanceOfPatternMatch.java b/src/main/java/org/openrewrite/staticanalysis/InstanceOfPatternMatch.java
index 0364fba44..35cc9e506 100644
--- a/src/main/java/org/openrewrite/staticanalysis/InstanceOfPatternMatch.java
+++ b/src/main/java/org/openrewrite/staticanalysis/InstanceOfPatternMatch.java
@@ -364,9 +364,7 @@ public String variableName(@Nullable JavaType type) {
                 return name;
             } else if (type instanceof JavaType.FullyQualified) {
                 String className = ((JavaType.FullyQualified) type).getClassName();
-                if (className.indexOf('.') > 0) {
-                    className = className.substring(className.lastIndexOf('.'));
-                }
+                className = className.substring(className.lastIndexOf('.') + 1);
                 String baseName = null;
                 switch (style) {
                     case SHORT:
diff --git a/src/test/java/org/openrewrite/staticanalysis/InstanceOfPatternMatchTest.java b/src/test/java/org/openrewrite/staticanalysis/InstanceOfPatternMatchTest.java
index 0d29e191f..c0b668e0c 100644
--- a/src/test/java/org/openrewrite/staticanalysis/InstanceOfPatternMatchTest.java
+++ b/src/test/java/org/openrewrite/staticanalysis/InstanceOfPatternMatchTest.java
@@ -221,6 +221,41 @@ void test(Object o) {
             );
         }
 
+        @Test
+        void conflictingVariableOfNestedType() {
+            rewriteRun(
+              //language=java
+              java(
+                """
+                  import java.util.Map;
+                  
+                  public class A {
+                      void test(Object o) {
+                          Map.Entry entry = null;
+                          if (o instanceof Map.Entry) {
+                            entry = (Map.Entry) o;
+                          }
+                          System.out.println(entry);
+                      }
+                  }
+                  """,
+                """
+                  import java.util.Map;
+                  
+                  public class A {
+                      void test(Object o) {
+                          Map.Entry entry = null;
+                          if (o instanceof Map.Entry entry1) {
+                            entry = entry1;
+                          }
+                          System.out.println(entry);
+                      }
+                  }
+                  """
+              )
+            );
+        }
+
         @Issue("https://github.com/openrewrite/rewrite/issues/2787")
         @Disabled
         @Test