[CodeIssues] Fix crashes in VariableDeclaredInWideScopeIssue.

ICSharpCode.NRefactory.CSharp/Refactoring/CodeIssues/VariableDeclaredInWideScopeIssue.cs

@@ -94,7 +94,7 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 				                                where block != null
 				                                select block).LastOrDefault();
 
-				if (mostNestedBlockStatement != null) {
+				if (mostNestedBlockStatement != null && mostNestedBlockStatement != rootNode) {
 					AddIssue(variableDeclarationStatement, context.TranslateString("Variable could be moved to a nested scope"),
 					         GetActions(variableDeclarationStatement, mostNestedBlockStatement));
 				}
@@ -112,7 +112,7 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 			{
 				var previousPath = GetPath(assumedRoot, leaves.First());
 				int lowestIndex = previousPath.Count - 1;
-				foreach (var leaf in leaves) {
+				foreach (var leaf in leaves.Skip(1)) {
 					var currentPath = GetPath(assumedRoot, leaf);
 					lowestIndex = GetLowestCommonAncestorIndex(previousPath, currentPath, lowestIndex);
 					previousPath = currentPath;
@@ -123,7 +123,7 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 			int GetLowestCommonAncestorIndex(IList<AstNode> path1, IList<AstNode> path2, int maxIndex)
 			{
 				var max = Math.Min(Math.Min(path1.Count, path2.Count), maxIndex);
-				for (int i = 0; i < max; i++) {
+				for (int i = 0; i <= max; i++) {
 					if (path1 [i] != path2 [i])
 						return i - 1;
 				}
@@ -136,7 +136,7 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 				do {
 					reversePath.Add(to);
 					to = to.Parent;
-				} while (to != from);
+				} while (to != from.Parent);
 				reversePath.Reverse();
 				return reversePath;
 			}

ICSharpCode.NRefactory.Tests/CSharp/CodeIssues/VariableDeclaredInWideScopeTests.cs

@@ -193,6 +193,24 @@ class A
 			Assert.AreEqual(0, issues.Count);
 		}
 		
+		[Test]
+		public void IgnoresVariablesOnlyUsedInOneScope()
+		{
+			var input = @"
+class A
+{
+	void F()
+	{
+		A a = new A();
+		a.F();
+		a.F();
+	}
+}";
+			TestRefactoringContext context;
+			var issues = GetIssues(new VariableDeclaredInWideScopeIssue(), input, out context);
+			Assert.AreEqual(0, issues.Count);
+		}
+		
 		[Test]
 		public void DoesNotSuggestMovingIntoLoop()
 		{
@@ -206,6 +224,25 @@ class A
 			val = 3;
 		}
 	}
+}";
+			TestRefactoringContext context;
+			var issues = GetIssues(new VariableDeclaredInWideScopeIssue(), input, out context);
+			Assert.AreEqual(0, issues.Count);
+		}
+		
+		[Test]
+		public void DoesNotSuggestMovingPastDependentCondition()
+		{
+			var input = @"
+class A
+{
+	void F()
+	{
+		int val = 2;
+		if (val == 2 || val == 1) {
+			val = 3;
+		}
+	}
 }";
 			TestRefactoringContext context;
 			var issues = GetIssues(new VariableDeclaredInWideScopeIssue(), input, out context);