Fix crash in ConvertToInitializer context action.

ICSharpCode.NRefactory.CSharp/Refactoring/CodeActions/ConvertToInitializer/StatementsToInitializerConverter.cs

@@ -124,12 +124,14 @@ bool TryHandleInitializer(AstNode node)
 				return false;
 			}
 			variableInitializer = variableDeclarationStatement.Variables.FirstOrNullObject();
-			if (variableInitializer.IsNull)
+			if (variableInitializer.IsNull || variableInitializer.Initializer.IsNull)
 				return false;
 			var sourceResolveResult = context.Resolve(variableInitializer.Initializer) as LocalResolveResult;
 			if (HasDependency(variableInitializer.Initializer) && !CanReplaceDependent(sourceResolveResult))
 				return false;
 			var targetResolveResult = context.Resolve(variableInitializer) as LocalResolveResult;
+			if (targetResolveResult == null)
+				return false;
 			AddNewVariable(targetResolveResult.Variable, variableInitializer.Initializer, node);
 			return true;
 		}

ICSharpCode.NRefactory.Tests/CSharp/CodeActions/ConvertToInitializer/ConvertToInitializerTests.cs

@@ -662,6 +662,20 @@ void F()
 		// And another statement to make the converter even try
 		s = """";
 	}
+}");
+		}
+
+		[Test]
+		public void DoesNotCrashOnVariableDeclarationWithoutInitializer()
+		{
+			TestWrongContext<ConvertToInitializerAction>(@"
+class TestClass
+{
+	void F()
+	{
+		TestClass $s1 = new TestClass();
+		TestClass s2;
+	}
 }");
 		}
 	}