Fix out var for expressions appearing in a lambda and not in a statement.

Author: siegfriedpammer

ICSharpCode.Decompiler.Tests/TestCases/Pretty/OutVariables.cs

@@ -72,5 +72,14 @@ public void M4()
 			GetObject(out dynamic obj);
 			obj.Method();
 		}
+
+		public void M5()
+		{
+			Func<bool> func = () => TryGet<object>(out var result) && result != null;
+			Func<bool> func2 = () => TryGet<object>(out var result) && result != null;
+
+			func();
+			func2();
+		}
 	}
 }

ICSharpCode.Decompiler/CSharp/Transforms/DeclareVariables.cs

@@ -776,11 +776,13 @@ private bool CanBeDeclaredAsOutVariable(VariableToDeclare v, out DirectionExpres
 				}
 				switch (node)
 				{
-					case IfElseStatement _:  // variable declared in if condition appears in parent scope
-					case ExpressionStatement _:
+					case IfElseStatement:  // variable declared in if condition appears in parent scope
+					case ExpressionStatement:
 						return node == v.InsertionPoint.nextNode;
-					case Statement _:
+					case Statement:
 						return false; // other statements (e.g. while) don't allow variables to be promoted to parent scope
+					case LambdaExpression lambda:
+						return lambda.Body == v.InsertionPoint.nextNode;
 				}
 			}
 			return false;