Revert "std.ComptimeStringMap: use tuple types"

This reverts commit 096d3ef.

This commit is not passing a very important CI test that was recently
added.

Author: andrewrk

lib/std/comptime_string_map.zig

@@ -5,8 +5,9 @@ const mem = std.mem;
 /// Works by separating the keys by length at comptime and only checking strings of
 /// equal length at runtime.
 ///
-/// `kvs_list` expects a list of `struct { []const u8, V }` (key-value pair) tuples.
-/// You can pass `struct { []const u8 }` (only keys) tuples if `V` is `void`.
+/// `kvs` expects a list literal containing list literals or an array/slice of structs
+/// where `.@"0"` is the `[]const u8` key and `.@"1"` is the associated value of type `V`.
+/// TODO: https://github.com/ziglang/zig/issues/4335
 pub fn ComptimeStringMap(comptime V: type, comptime kvs_list: anytype) type {
     const precomputed = comptime blk: {
         @setEvalBranchQuota(2000);
@@ -96,26 +97,32 @@ test "ComptimeStringMap list literal of list literals" {
 }
 
 test "ComptimeStringMap array of structs" {
-    const KV = struct { []const u8, TestEnum };
+    const KV = struct {
+        @"0": []const u8,
+        @"1": TestEnum,
+    };
     const map = ComptimeStringMap(TestEnum, [_]KV{
-        .{ "these", .D },
-        .{ "have", .A },
-        .{ "nothing", .B },
-        .{ "incommon", .C },
-        .{ "samelen", .E },
+        .{ .@"0" = "these", .@"1" = .D },
+        .{ .@"0" = "have", .@"1" = .A },
+        .{ .@"0" = "nothing", .@"1" = .B },
+        .{ .@"0" = "incommon", .@"1" = .C },
+        .{ .@"0" = "samelen", .@"1" = .E },
     });
 
     try testMap(map);
 }
 
 test "ComptimeStringMap slice of structs" {
-    const KV = struct { []const u8, TestEnum };
+    const KV = struct {
+        @"0": []const u8,
+        @"1": TestEnum,
+    };
     const slice: []const KV = &[_]KV{
-        .{ "these", .D },
-        .{ "have", .A },
-        .{ "nothing", .B },
-        .{ "incommon", .C },
-        .{ "samelen", .E },
+        .{ .@"0" = "these", .@"1" = .D },
+        .{ .@"0" = "have", .@"1" = .A },
+        .{ .@"0" = "nothing", .@"1" = .B },
+        .{ .@"0" = "incommon", .@"1" = .C },
+        .{ .@"0" = "samelen", .@"1" = .E },
     };
     const map = ComptimeStringMap(TestEnum, slice);
 
@@ -134,13 +141,15 @@ fn testMap(comptime map: anytype) !void {
 }
 
 test "ComptimeStringMap void value type, slice of structs" {
-    const KV = struct { []const u8 };
+    const KV = struct {
+        @"0": []const u8,
+    };
     const slice: []const KV = &[_]KV{
-        .{"these"},
-        .{"have"},
-        .{"nothing"},
-        .{"incommon"},
-        .{"samelen"},
+        .{ .@"0" = "these" },
+        .{ .@"0" = "have" },
+        .{ .@"0" = "nothing" },
+        .{ .@"0" = "incommon" },
+        .{ .@"0" = "samelen" },
     };
     const map = ComptimeStringMap(void, slice);
 

lib/std/meta.zig

@@ -115,10 +115,16 @@ pub fn stringToEnum(comptime T: type, str: []const u8) ?T {
     // - https://github.com/ziglang/zig/issues/3863
     if (@typeInfo(T).Enum.fields.len <= 100) {
         const kvs = comptime build_kvs: {
-            const EnumKV = struct { []const u8, T };
+            // In order to generate an array of structs that play nice with anonymous
+            // list literals, we need to give them "0" and "1" field names.
+            // TODO https://github.com/ziglang/zig/issues/4335
+            const EnumKV = struct {
+                @"0": []const u8,
+                @"1": T,
+            };
             var kvs_array: [@typeInfo(T).Enum.fields.len]EnumKV = undefined;
             inline for (@typeInfo(T).Enum.fields) |enumField, i| {
-                kvs_array[i] = .{ enumField.name, @field(T, enumField.name) };
+                kvs_array[i] = .{ .@"0" = enumField.name, .@"1" = @field(T, enumField.name) };
             }
             break :build_kvs kvs_array[0..];
         };