diff --git a/lib/std/core/array.c3 b/lib/std/core/array.c3
index 33d90236b..ab00fe671 100644
--- a/lib/std/core/array.c3
+++ b/lib/std/core/array.c3
@@ -55,7 +55,7 @@ macro rindex_of(array, element)
  * @require @typeis(arr1[0], $typeof(arr2[0])) "Arrays must have the same type"
  * @ensure result.len == arr1.len + arr2.len
  **/
-macro concat_new(arr1, arr2, Allocator allocator = allocator::heap())
+macro concat(arr1, arr2, Allocator allocator) @nodiscard
 {
 	var $Type = $typeof(arr1[0]);
 	$Type[] result = allocator::alloc_array(allocator, $Type, arr1.len + arr2.len);
@@ -69,6 +69,21 @@ macro concat_new(arr1, arr2, Allocator allocator = allocator::heap())
 	}
 	return result;
 }
+/**
+ * Concatenate two arrays or slices, returning a slice containing the concatenation of them.
+ *
+ * @param [in] arr1
+ * @param [in] arr2
+ * @param [&inout] allocator "The allocator to use, default is the heap allocator"
+ * @require @typekind(arr1) == SLICE || @typekind(arr1) == ARRAY
+ * @require @typekind(arr2) == SLICE || @typekind(arr2) == ARRAY
+ * @require @typeis(arr1[0], $typeof(arr2[0])) "Arrays must have the same type"
+ * @ensure result.len == arr1.len + arr2.len
+ **/
+macro concat_new(arr1, arr2, Allocator allocator = allocator::heap()) @nodiscard
+{
+	return concat(arr1, arr2, allocator);
+}
 
 /**
  * Concatenate two arrays or slices, returning a slice containing the concatenation of them,
@@ -81,7 +96,7 @@ macro concat_new(arr1, arr2, Allocator allocator = allocator::heap())
  * @require @typeis(arr1[0], $typeof(arr2[0])) "Arrays must have the same type"
  * @ensure result.len == arr1.len + arr2.len
  **/
-macro tconcat(arr1, arr2) => concat(arr1, arr2, allocator::temp());
+macro tconcat(arr1, arr2) @nodiscard => concat(arr1, arr2, allocator::temp());
 
 module std::core::array::slice(<Type>);
 
diff --git a/src/compiler/sema_expr.c b/src/compiler/sema_expr.c
index f4068e4e0..d90568a9c 100644
--- a/src/compiler/sema_expr.c
+++ b/src/compiler/sema_expr.c
@@ -1723,7 +1723,7 @@ SPLAT_NORMAL:;
 		if (!sema_analyse_parameter(context, arg, params[i], callee->definition, optional, no_match_ref, callee->macro)) return false;
 		actual_args[i] = arg;
 	}
-
+	if (num_args) last = args[num_args - 1];
 	call->call_expr.arguments = args;
 	// 17. Set default values.
 	for (unsigned i = 0; i < func_param_count; i++)
diff --git a/test/unit/stdlib/core/array.c3 b/test/unit/stdlib/core/array.c3
index 58473c75c..6c11b4b19 100644
--- a/test/unit/stdlib/core/array.c3
+++ b/test/unit/stdlib/core/array.c3
@@ -21,11 +21,11 @@ fn void! find_subarray()
 fn void! concat()
 {
 	int[3] a = { 1, 2, 3 };
-	array::concat_new(a, a);
-	array::concat_new(a[..], a[..]);
-	array::concat_new(a[:0], a[:0]);
-	array::concat_new(int[2] { 1, 2 }, a[:0]);
-	array::concat_new(a[:0], int[2] { 1, 2 });
+	(void)array::concat_new(a, a);
+	(void)array::concat_new(a[..], a[..]);
+	(void)array::concat_new(a[:0], a[:0]);
+	(void)array::concat_new(int[2] { 1, 2 }, a[:0]);
+	(void)array::concat_new(a[:0], int[2] { 1, 2 });
 	int[] c = array::concat_new(a[1..2], a);
 	assert (c == int[]{ 2, 3, 1, 2, 3 });
 }