- Improve error message when a keyword is used a block parameter. #3275

Author: lerno

releasenotes.md

@@ -9,6 +9,7 @@
 - Add json pretty print.
 - `$$atomic_store` and `$$atomic_load` takes an alignment parameter.
 - `$vaarg[^1]` is supported. #3276
+- Improve error message when a keyword is used a block parameter. #3275
 
 ### Stdlib changes
 - Add math::TAU / math::TWO_PI

src/compiler/parse_expr.c

@@ -1035,6 +1035,11 @@ static Expr *parse_call_expr(ParseContext *c, Expr *left, SourceLoc *lhs_start)
 	{
 		if (!parse_next_may_be_type_or_ident(c))
 		{
+			if (token_is_keyword_ident(c->tok) && c->span.row == c->prev_span.row)
+			{
+				PRINT_ERROR_HERE("'%s' is a keyword, and can't be used as a parameter name.", symstr(c));
+				return poisoned_expr;
+			}
 			PRINT_ERROR_LAST("Expected an ending ')'. Did you forget a ')' before this ';'?");
 			return poisoned_expr;
 		}

test/test_suite/macros/body_arg_is_keyword.c3

@@ -0,0 +1,9 @@
+module test;
+import std;
+fn void main()
+{
+	HashMap{String, String} my_map;
+	my_map.@each(;module, migration) // #error:  'module' is a keyword, and can't be used
+	{
+	};
+}