Use List<T>.ToArray() in places (#22101)

* Use ReadOnlySpan.ToArray in places

* Use List.ToArray

* Don't take .Length in to local and use as loop condition

Author: benaadams

src/System.Private.CoreLib/shared/System/Globalization/DateTimeFormat.cs

@@ -1391,9 +1391,8 @@ internal static string[] GetAllDateTimes(DateTime dateTime, DateTimeFormatInfo d
                     results.Add(strings[j]);
                 }
             }
-            string[] value = new string[results.Count];
-            results.CopyTo(0, value, 0, results.Count);
-            return (value);
+
+            return results.ToArray();
         }
 
         // This is a placeholder for an MDA to detect when the user is using a

src/System.Private.CoreLib/src/System/RtType.cs

@@ -4097,8 +4097,7 @@ public override object InvokeMember(
                 if (results != null)
                 {
                     Debug.Assert(results.Count > 1);
-                    finalists = new MethodInfo[results.Count];
-                    results.CopyTo(finalists);
+                    finalists = results.ToArray();
                 }
             }
 
@@ -4149,8 +4148,7 @@ public override object InvokeMember(
                 if (results != null)
                 {
                     Debug.Assert(results.Count > 1);
-                    finalists = new MethodInfo[results.Count];
-                    results.CopyTo(finalists);
+                    finalists = results.ToArray();
                 }
             }
 
@@ -4342,8 +4340,6 @@ internal object CreateInstanceImpl(
             if (args == null)
                 args = Array.Empty<object>();
 
-            int argCnt = args.Length;
-
             // Without a binder we need to do use the default binder...
             if (binder == null)
                 binder = DefaultBinder;
@@ -4352,7 +4348,7 @@ internal object CreateInstanceImpl(
             // so a call to GetMemberCons would fail
             bool publicOnly = (bindingAttr & BindingFlags.NonPublic) == 0;
             bool wrapExceptions = (bindingAttr & BindingFlags.DoNotWrapExceptions) == 0;
-            if (argCnt == 0 && (bindingAttr & BindingFlags.Public) != 0 && (bindingAttr & BindingFlags.Instance) != 0
+            if (args.Length == 0 && (bindingAttr & BindingFlags.Public) != 0 && (bindingAttr & BindingFlags.Instance) != 0
                 && (IsGenericCOMObjectImpl() || IsValueType))
             {
                 server = CreateInstanceDefaultCtor(publicOnly, false, true, wrapExceptions);
@@ -4363,8 +4359,8 @@ internal object CreateInstanceImpl(
                 List<MethodBase> matches = new List<MethodBase>(candidates.Length);
 
                 // We cannot use Type.GetTypeArray here because some of the args might be null
-                Type[] argsType = new Type[argCnt];
-                for (int i = 0; i < argCnt; i++)
+                Type[] argsType = new Type[args.Length];
+                for (int i = 0; i < args.Length; i++)
                 {
                     if (args[i] != null)
                     {
@@ -4378,16 +4374,13 @@ internal object CreateInstanceImpl(
                         matches.Add(candidates[i]);
                 }
 
-                MethodBase[] cons = new MethodBase[matches.Count];
-                matches.CopyTo(cons);
-                if (cons != null && cons.Length == 0)
-                    cons = null;
-
-                if (cons == null)
+                if (matches.Count == 0)
                 {
                     throw new MissingMethodException(SR.Format(SR.MissingConstructor_Name, FullName));
                 }
 
+                MethodBase[] cons = matches.ToArray();
+
                 MethodBase invokeMethod;
                 object state = null;