Better type mapping

compiler/NubLang/Syntax/Parser.cs

@@ -807,9 +807,18 @@ public sealed class Parser
 
         if (TryExpectSymbol(Symbol.OpenBracket))
         {
-            ExpectSymbol(Symbol.CloseBracket);
-            var baseType = ParseType();
-            return new ArrayTypeSyntax(GetTokens(startIndex), baseType);
+            if (TryExpectIntLiteral(out var intLiteral))
+            {
+                ExpectSymbol(Symbol.CloseBracket);
+                var baseType = ParseType();
+                return new ConstArrayTypeSyntax(GetTokens(startIndex), baseType, int.Parse(intLiteral.Value));
+            }
+            else
+            {
+                ExpectSymbol(Symbol.CloseBracket);
+                var baseType = ParseType();
+                return new ArrayTypeSyntax(GetTokens(startIndex), baseType);
+            }
         }
 
         throw new ParseException(Diagnostic
@@ -930,6 +939,19 @@ public sealed class Parser
         return identifier;
     }
 
+    private bool TryExpectIntLiteral([NotNullWhen(true)] out IntLiteralToken? stringLiteral)
+    {
+        if (CurrentToken is IntLiteralToken token)
+        {
+            stringLiteral = token;
+            Next();
+            return true;
+        }
+
+        stringLiteral = null;
+        return false;
+    }
+
     private FloatLiteralToken ExpectFloatLiteral()
     {
         var token = ExpectToken();