aro: stop depending on ArrayList default field values

lib/compiler/aro/aro/InitList.zig

@@ -22,9 +22,15 @@ const Item = struct {
 
 const InitList = @This();
 
-list: std.ArrayList(Item) = .empty,
-node: Node.OptIndex = .null,
-tok: TokenIndex = 0,
+list: std.ArrayList(Item),
+node: Node.OptIndex,
+tok: TokenIndex,
+
+pub const empty: InitList = .{
+    .list = .empty,
+    .node = .null,
+    .tok = 0,
+};
 
 /// Deinitialize freeing all memory.
 pub fn deinit(il: *InitList, gpa: Allocator) void {
@@ -43,7 +49,7 @@ pub fn find(il: *InitList, gpa: Allocator, index: u64) !*InitList {
     if (il.list.items.len == 0) {
         const item = try il.list.addOne(gpa);
         item.* = .{
-            .list = .{},
+            .list = .empty,
             .index = index,
         };
         return &item.list;
@@ -51,7 +57,7 @@ pub fn find(il: *InitList, gpa: Allocator, index: u64) !*InitList {
         // Append a new value to the end of the list.
         const new = try il.list.addOne(gpa);
         new.* = .{
-            .list = .{},
+            .list = .empty,
             .index = index,
         };
         return &new.list;
@@ -70,7 +76,7 @@ pub fn find(il: *InitList, gpa: Allocator, index: u64) !*InitList {
 
     // Insert a new value into a sorted position.
     try il.list.insert(gpa, left, .{
-        .list = .{},
+        .list = .empty,
         .index = index,
     });
     return &il.list.items[left].list;
@@ -78,7 +84,7 @@ pub fn find(il: *InitList, gpa: Allocator, index: u64) !*InitList {
 
 test "basic usage" {
     const gpa = testing.allocator;
-    var il: InitList = .{};
+    var il: InitList = .empty;
     defer il.deinit(gpa);
 
     {

lib/compiler/aro/aro/Parser.zig

@@ -3977,7 +3977,7 @@ fn initializer(p: *Parser, init_qt: QualType) Error!Result {
         final_init_qt = .invalid;
     }
 
-    var il: InitList = .{};
+    var il: InitList = .empty;
     defer il.deinit(p.comp.gpa);
 
     try p.initializerItem(&il, final_init_qt, l_brace);
@@ -4028,12 +4028,12 @@ fn initializerItem(p: *Parser, il: *InitList, init_qt: QualType, l_brace: TokenI
                     try p.err(first_tok, .initializer_overrides, .{});
                     try p.err(item.il.tok, .previous_initializer, .{});
                     item.il.deinit(gpa);
-                    item.il.* = .{};
+                    item.il.* = .empty;
                 }
                 try p.initializerItem(item.il, item.qt, inner_l_brace);
             } else {
                 // discard further values
-                var tmp_il: InitList = .{};
+                var tmp_il: InitList = .empty;
                 defer tmp_il.deinit(gpa);
                 try p.initializerItem(&tmp_il, .invalid, inner_l_brace);
                 if (!warned_excess) try p.err(first_tok, switch (init_qt.base(p.comp).type) {

lib/compiler/aro/aro/Toolchain.zig

@@ -43,13 +43,13 @@ const Toolchain = @This();
 driver: *Driver,
 
 /// The list of toolchain specific path prefixes to search for libraries.
-library_paths: PathList = .{},
+library_paths: PathList = .empty,
 
 /// The list of toolchain specific path prefixes to search for files.
-file_paths: PathList = .{},
+file_paths: PathList = .empty,
 
 /// The list of toolchain specific path prefixes to search for programs.
-program_paths: PathList = .{},
+program_paths: PathList = .empty,
 
 selected_multilib: Multilib = .{},