Const slice lengths were not always detected as constant.

releasenotes.md

@@ -21,6 +21,7 @@
 - Non-const macros may not return untyped lists.
 - `$for` ct-state not properly popped.
 - Inline `r / complex` for complex numbers fixed.
+- Const slice lengths were not always detected as constant.
 
 ### Stdlib changes
 

src/compiler/sema_casts.c

@@ -2214,7 +2214,7 @@ static void cast_slice_to_bool(Expr *expr, Type *type)
 	}
 	if (expr_is_const_slice(expr))
 	{
-		expr_rewrite_const_bool(expr, type, expr->const_expr.slice_init != NULL);
+		expr_rewrite_const_bool(expr, type, expr->const_expr.slice_init != NULL && expr->const_expr.slice_init->kind != CONST_INIT_ZERO);
 		return;
 	}
 	Expr *inner = expr_copy(expr);

src/compiler/sema_const.c

@@ -12,7 +12,17 @@ ArrayIndex sema_len_from_const(Expr *expr)
 	// We also handle the case where we have a cast from a const array.
 	if (!sema_cast_const(expr))
 	{
-		if (type_flatten(expr->type)->type_kind != TYPE_SLICE) return -1;
+		Type *flat = type_flatten(expr->type);
+		switch (flat->type_kind)
+		{
+			case TYPE_ARRAY:
+			case TYPE_VECTOR:
+				return flat->array.len;
+			case TYPE_SLICE:
+				break;
+			default:
+				return -1;
+		}
 		if (expr->expr_kind == EXPR_SLICE)
 		{
 			return range_const_len(&expr->slice_expr.range);

src/compiler/sema_expr.c

@@ -5889,28 +5889,18 @@ CHECK_DEEPER:
 	// 9. Fix hard coded function `len` on slices and arrays
 	if (kw == kw_len)
 	{
+		ArrayIndex index = sema_len_from_const(current_parent);
+		if (index > -1)
+		{
+			expr_rewrite_const_int(expr, type_isz, index);
+			return true;
+		}
 		if (flat_type->type_kind == TYPE_SLICE)
 		{
-			// Handle literal "foo".len which is now a slice.
-			sema_expr_flatten_const_ident(current_parent);
-			if (expr_is_const_string(current_parent))
-			{
-				expr_rewrite_const_int(expr, type_isz, current_parent->const_expr.bytes.len);
-				return true;
-			}
 			expr_rewrite_slice_len(expr, current_parent, type_usz);
 			return true;
 		}
-		if (flat_type->type_kind == TYPE_ARRAY || flat_type->type_kind == TYPE_VECTOR)
-		{
-			expr_rewrite_const_int(expr, type_isz, flat_type->array.len);
-			return true;
-		}
-		if (flat_type->type_kind == TYPE_UNTYPED_LIST)
-		{
-			expr_rewrite_const_int(expr, type_isz, vec_size(current_parent->const_expr.untyped_list));
-			return true;
-		}
+		assert(flat_type->type_kind != TYPE_ARRAY && flat_type->type_kind != TYPE_VECTOR);
 	}
 	if (flat_type->type_kind == TYPE_TYPEID)
 	{

test/test_suite/slices/const_slice_len.c3

@@ -0,0 +1,6 @@
+fn int main()
+{
+	const char[][] SEQUENCE = { { 1 }};
+	var $i = SEQUENCE.len;
+	return 0;
+}

test/test_suite/struct/inline_slice_access_2088.c3t

@@ -15,8 +15,5 @@ fn int main()
 /* #expect: test.ll
 
 entry:
-  %literal = alloca %Foo, align 8
-  call void @llvm.memset.p0.i64(ptr align 8 %literal, i8 0, i64 16, i1 false)
-  %ptradd = getelementptr inbounds i8, ptr %literal, i64 8
   ret i32 0
 }