Lint for redundant positional arguments.

Content.Tests/DMProject/Tests/Call/RedundantPositionalKey.dm

@@ -0,0 +1,8 @@
+// COMPILE ERROR
+
+#pragma PointlessPositionalArgument error
+
+/proc/test()
+
+/proc/RunTest()
+	test(1 = "a", 2 = "b", 3 = "c") // 3 unnecessary positional keys

DMCompiler/Compiler/CompilerError.cs

@@ -50,6 +50,7 @@
     SuspiciousMatrixCall = 2207, // Calling matrix() with seemingly the wrong arguments
     FallbackBuiltinArgument = 2208, // A builtin (sin(), cos(), etc) with an invalid/fallback argument
     PointlessScopeOperator = 2209,
+    PointlessPositionalArgument = 2210,
     MalformedRange = 2300,
     InvalidRange = 2301,
     InvalidSetStatement = 2302,
@@ -138,7 +139,7 @@
 /// This should be ideally used for exceptions that are the fault of the compiler itself, <br/>
 /// like an abnormal state being reached or something.
 /// </summary>
 public sealed class CompileAbortException : CompileErrorException {
     public CompileAbortException(CompilerEmission error) : base(error) {
     }
 
@@ -149,6 +150,6 @@
     }
 }
 
 public sealed class UnknownIdentifierException(Location location, string identifierName) : CompileErrorException(location, $"Unknown identifier \"{identifierName}\"") {
     public string IdentifierName = identifierName;
 }

DMCompiler/DM/DMExpression.cs

@@ -109,7 +109,14 @@ public ArgumentList(Location location, DMObject dmObject, DMProc proc, DMASTCall
                     break;
                 case Expressions.Number keyNum:
                     //Replaces an ordered argument
-                    argIndex = (int)keyNum.Value;
+                    var newIdx = (int)keyNum.Value - 1;
+
+                    if (newIdx == argIndex) {
+                        DMCompiler.Emit(WarningCode.PointlessPositionalArgument, key.Location,
+                            $"The argument at index {argIndex + 1} is a positional argument with a redundant index (\"{argIndex + 1} = value\" at argument {argIndex + 1}). This does not function like a named argument and is likely a mistake.");
+                    }
+
+                    argIndex = newIdx;
                     break;
                 case Expressions.Resource _:
                 case Expressions.ConstantPath _:

DMCompiler/DMStandard/DefaultPragmaConfig.dm

@@ -30,6 +30,7 @@
 #pragma MissingInterpolatedExpression warning
 #pragma AmbiguousResourcePath warning
 #pragma SuspiciousSwitchCase warning
+#pragma PointlessPositionalArgument warning
 // NOTE: The next few pragmas are for OpenDream's experimental type checker
 // This feature is still in development, elevating these pragmas outside of local testing is discouraged
 // An RFC to finalize this feature is coming soon(TM)