diff --git a/docs/TODO.txt b/docs/TODO.txt
index a65fe9a..409ceb3 100644
--- a/docs/TODO.txt
+++ b/docs/TODO.txt
@@ -21,12 +21,13 @@ DONE: function returns can have specified types
 DONE: closures are explicitly supported
 DONE: functions are first-class citizens
 DONE: functions take a set number of parameters
+DONE: functions last argument can be a rest parameter
 
 
 TODO: functions return a set number of values
-TODO: functions last argument can be a rest parameter
-TODO: assert needs to kill the whole script
+TODO: assert needs to kill the whole script, not just functions
 
+TODO: ternary operator
 TODO: Nullish types
 TODO: A way to check the type of a variable (typeOf keyword)
 TODO: a = b = c = 1; ?
@@ -34,3 +35,5 @@ TODO: are compounds shallow or deep copies?
 TODO: Assertion-based test scripts
 TODO: standard library
 TODO: external runner library
+TODO: document how it all works
+TODO: third output stream, for parser/compiler/interpreter errors
diff --git a/scripts/error-test.toy b/scripts/error-test.toy
new file mode 100644
index 0000000..e69de29
diff --git a/source/interpreter.c b/source/interpreter.c
index c39c16a..0166725 100644
--- a/source/interpreter.c
+++ b/source/interpreter.c
@@ -782,9 +782,15 @@ static bool execFnCall(Interpreter* interpreter) {
 	LiteralArray* paramArray = AS_ARRAY(inner.literalCache.literals[ readShort(inner.bytecode, &inner.count) ]);
 	LiteralArray* returnArray = AS_ARRAY(inner.literalCache.literals[ readShort(inner.bytecode, &inner.count) ]);
 
+	//get the rest param, if it exists
+	Literal restParam = TO_NULL_LITERAL;
+	if (paramArray->count >= 2 && AS_TYPE(paramArray->literals[ paramArray->count -1 ]).typeOf == LITERAL_FUNCTION_ARG_REST) {
+		restParam = paramArray->literals[ paramArray->count -2 ];
+	}
+
 	//check the param total is correct
-	if (paramArray->count != arguments.count * 2) {
-		printf(ERROR "ERROR: Incorrect number of arguments passed to function \"\n");
+	if ((IS_NULL(restParam) && paramArray->count != arguments.count * 2) || (!IS_NULL(restParam) && paramArray->count -2 > arguments.count * 2)) {
+		printf(ERROR "ERROR: Incorrect number of arguments passed to function \"");
 		printLiteral(identifier);
 		printf("\"\n" RESET);
 
@@ -795,16 +801,55 @@ static bool execFnCall(Interpreter* interpreter) {
 		return false;
 	}
 
-	for (int i = 0; i < paramArray->count; i += 2) { //contents is the indexes of identifier & type
+	//contents is the indexes of identifier & type
+	for (int i = 0; i < paramArray->count - (IS_NULL(restParam) ? 0 : 2); i += 2) { //don't count the rest parameter, if present
 		//declare and define each entry in the scope
 		if (!declareScopeVariable(inner.scope, paramArray->literals[i], paramArray->literals[i + 1])) {
 			printf(ERROR "[internal] Could not re-declare parameter\n" RESET);
+			//free, and skip out
+			freeLiteralArray(&arguments);
 			freeInterpreter(&inner);
 			return false;
 		}
 
 		if (!setScopeVariable(inner.scope, paramArray->literals[i], popLiteralArray(&arguments), false)) {
 			printf(ERROR "[internal] Could not define parameter (bad type?)\n" RESET);
+			//free, and skip out
+			freeLiteralArray(&arguments);
+			freeInterpreter(&inner);
+			return false;
+		}
+	}
+
+	//if using rest, pack the optional extra arguments into the rest parameter (array)
+	if (!IS_NULL(restParam)) {
+		LiteralArray rest;
+		initLiteralArray(&rest);
+
+		while (arguments.count > 0) {
+			pushLiteralArray(&rest, popLiteralArray(&arguments));
+		}
+
+		Literal restType = TO_TYPE_LITERAL(LITERAL_ARRAY, true);
+		TYPE_PUSH_SUBTYPE(&restType, TO_TYPE_LITERAL(LITERAL_ANY, false));
+
+		//declare & define the rest parameter
+		if (!declareScopeVariable(inner.scope, restParam, restType)) {
+			printf(ERROR "[internal] Could not declare rest parameter\n" RESET);
+			//free, and skip out
+			freeLiteral(restType);
+			freeLiteralArray(&rest);
+			freeLiteralArray(&arguments);
+			freeInterpreter(&inner);
+			return false;
+		}
+
+		if (!setScopeVariable(inner.scope, restParam, TO_ARRAY_LITERAL(&rest), false)) {
+			printf(ERROR "[internal] Could not define rest parameter\n" RESET);
+			//free, and skip out
+			freeLiteral(restType);
+			freeLiteralArray(&rest);
+			freeLiteralArray(&arguments);
 			freeInterpreter(&inner);
 			return false;
 		}
@@ -1083,7 +1128,7 @@ static void execInterpreter(Interpreter* interpreter) {
 
 static void readInterpreterSections(Interpreter* interpreter) {
 	//data section
-	const short literalCount = readShort(interpreter->bytecode, &interpreter->count);
+	const unsigned short literalCount = readShort(interpreter->bytecode, &interpreter->count);
 
 	if (command.verbose) {
 		printf(NOTICE "Reading %d literals\n" RESET, literalCount);
diff --git a/source/literal.c b/source/literal.c
index fa9a777..425fc84 100644
--- a/source/literal.c
+++ b/source/literal.c
@@ -305,6 +305,10 @@ void printLiteralCustom(Literal literal, void (printFn)(const char*)) {
 		case LITERAL_ANY:
 			printFn("(any)");
 		break;
+
+		default:
+			//should never be seen
+			fprintf(stderr, ERROR "[internal] Unrecognized literal type in print: %d\n" RESET, literal.type);
 	}
 }
 
@@ -489,7 +493,12 @@ bool literalsAreEqual(Literal lhs, Literal rhs) {
 			return true;
 
 		case LITERAL_FUNCTION_INTERMEDIATE:
-			fprintf(stderr, ERROR "[internal] Can't compare functions\n" RESET);
+			fprintf(stderr, ERROR "[internal] Can't compare intermediate functions\n" RESET);
+			return false;
+
+		default:
+			//should never be seen
+			fprintf(stderr, ERROR "[internal] Unrecognized literal type in equality: %d\n" RESET, lhs.type);
 			return false;
 	}
 
diff --git a/source/literal.h b/source/literal.h
index 973f247..d7ff370 100644
--- a/source/literal.h
+++ b/source/literal.h
@@ -19,6 +19,7 @@ typedef enum {
 	LITERAL_TYPE,
 	LITERAL_TYPE_INTERMEDIATE, //used to process types in the compiler only
 	LITERAL_FUNCTION_INTERMEDIATE, //used to process functions in the compiler only
+	LITERAL_FUNCTION_ARG_REST, //used to process function rest parameters
 	// LITERAL_FUNCTION_NATIVE, //for handling native functions
 	LITERAL_ANY, //used by the type system only
 } LiteralType;
diff --git a/source/parser.c b/source/parser.c
index ed9b6b4..bc3a431 100644
--- a/source/parser.c
+++ b/source/parser.c
@@ -1419,8 +1419,7 @@ static void fnDecl(Parser* parser, Node** nodeHandle) {
 				Literal argIdentifier = _toIdentifierLiteral(cpy, strlen(cpy)); //BUGFIX: use this instead of the macro
 
 				//set the type (array of any types)
-				Literal argTypeLiteral = TO_TYPE_LITERAL(LITERAL_ARRAY, false);
-				TYPE_PUSH_SUBTYPE(&argTypeLiteral, TO_TYPE_LITERAL(LITERAL_ANY, false));
+				Literal argTypeLiteral = TO_TYPE_LITERAL(LITERAL_FUNCTION_ARG_REST, false);
 
 				//emit the node to the argument list (grow the node if needed)
 				if (argumentNode->fnCollection.capacity < argumentNode->fnCollection.count + 1) {
diff --git a/test/functions.toy b/test/functions.toy
index 8a1ee05..00778e5 100644
--- a/test/functions.toy
+++ b/test/functions.toy
@@ -30,7 +30,7 @@ var tally = make();
 assert tally() == 1 && tally() == 2, "Closures failed";
 
 
-//expressions as arguments
+//test expressions as arguments
 fn argFn() {
 	return 42;
 }
@@ -42,4 +42,14 @@ fn outerFn(val) {
 outerFn(argFn());
 
 
+//test extra parameters
+fn extra(one, two, ...rest) {
+	assert rest == ["three", "four", "five", "six", "seven"], "rest parameters failed";
+}
+
+extra("one", "two", "three", "four", "five", "six", "seven");
+
+
+
+
 print "All good";
\ No newline at end of file