cleanup warnings

Author: tomlm

src/XTerm.NET.Tests/Buffer/BufferTests.cs

@@ -632,7 +632,7 @@ public void ScrollUp_PreservesScrollbackContent()
         // Mark each initial line with a unique identifier
         for (int i = 0; i < 5; i++)
         {
-            var line = buffer.Lines[i];
+            var line = buffer.Lines[i]!;
             var cell = new BufferCell(((char)('A' + i)).ToString(), 1, AttributeData.Default);
             line.SetCell(0, ref cell);
         }

src/XTerm.NET/Buffer/TerminalBuffer.cs

@@ -22,8 +22,8 @@ public class TerminalBuffer
     /// The absolute line index of the top of the viewport in the buffer.
     /// In XTerm.js this is 'ydisp'. This represents the current scroll position.
     /// </summary>
-    public int ViewportY 
-    { 
+    public int ViewportY
+    {
         get => _yDisp;
         set => _yDisp = Math.Clamp(value, 0, _yBase);
     }
@@ -144,20 +144,20 @@ public void ScrollUp(int lines, bool isWrapped = false)
                 // When scrollTop is 0, the top line goes into scrollback.
                 // In xterm.js: push new line first, then increment yBase and yDisp.
                 // This causes the circular list to potentially recycle the oldest line.
-                
+
                 // Check if we're at max capacity - if so, yBase stays the same but 
                 // the buffer rotates. If not, yBase increments.
                 var willBeRecycled = _lines.Length >= _lines.MaxLength;
-                
+
                 // Push the new line at the end (bottom of screen in buffer terms)
                 _lines.Push(newLine);
-                
+
                 // Only increment yBase if the buffer didn't recycle
                 if (!willBeRecycled)
                 {
                     _yBase++;
                 }
-                
+
                 // If yDisp was at the bottom, keep it there
                 if (_yDisp + 1 < _yBase)
                 {
@@ -348,9 +348,12 @@ public string PrintViewport()
         for (int i = 0; i < _rows; i++)
         {
             var line = GetLine(_yDisp + i);
-            foreach(var cell in line)
+            if (line != null)
             {
-                sb.Append(cell.Content);
+                foreach (var cell in line)
+                {
+                    sb.Append(cell.Content);
+                }
             }
             sb.AppendLine();
         }

src/XTerm.NET/InputHandler.cs

@@ -108,8 +108,6 @@ public void Print(string data)
                 {
                     return; // Successfully combined, don't create new cell
                 }
-                else
-                    ;
                 // If we can't combine (e.g., at start of line), fall through to normal handling
             }
         }

src/XTerm.NET/Parser/EscapeSequenceParser.cs

@@ -13,7 +13,6 @@ public class EscapeSequenceParser
 {
     private ParserState _state;
     private readonly Params _params;
-    private int _currentParam;
     private readonly StringBuilder _collect;
     private readonly StringBuilder _osc;
     private readonly StringBuilder _dcs;
@@ -53,7 +52,6 @@ public EscapeSequenceParser()
     {
         _state = ParserState.Ground;
         _params = new Params();
-        _currentParam = 0;
         _collect = new StringBuilder();
         _osc = new StringBuilder();
         _dcs = new StringBuilder();
@@ -255,7 +253,6 @@ private void Transition(ParserState newState)
                 {
                     _params.Reset();
                     _collect.Clear();
-                    _currentParam = 0;
                 }
                 break;
         }
@@ -269,7 +266,6 @@ private void Transition(ParserState newState)
             case ParserState.DcsEntry:
                 _params.Reset();
                 _collect.Clear();
-                _currentParam = 0;
                 _params.AddParam(0);
                 break;
 
@@ -305,7 +301,6 @@ private void Param(int code)
         if (code == 0x3B) // ;
         {
             _params.AddParam(0);
-            _currentParam = 0;
         }
         else if (code >= 0x30 && code <= 0x39) // 0-9
         {
@@ -375,7 +370,6 @@ public void Reset()
     {
         _state = ParserState.Ground;
         _params.Reset();
-        _currentParam = 0;
         _collect.Clear();
         _osc.Clear();
         _dcs.Clear();