start: refactor callMain return type checking

1 files changed, 13 insertions, 20 deletions

diff --git a/lib/std/start.zig b/lib/std/start.zig
index 187048dfd3..0f169f112d 100644
--- a/lib/std/start.zig
+++ b/lib/std/start.zig
@@ -497,21 +497,19 @@ fn mainWithoutEnv(c_argc: c_int, c_argv: [*][*:0]c_char) callconv(.C) c_int {
 const bad_main_ret = "expected return type of main to be 'void', '!void', 'noreturn', 'u8', or '!u8'";
 
 pub inline fn callMain() u8 {
-    switch (@typeInfo(@typeInfo(@TypeOf(root.main)).Fn.return_type.?)) {
-        .NoReturn => {
-            root.main();
-        },
-        .Void => {
+    const ReturnType = @typeInfo(@TypeOf(root.main)).Fn.return_type.?;
+
+    switch (ReturnType) {
+        void => {
             root.main();
             return 0;
         },
-        .Int => |info| {
-            if (info.bits != 8 or info.signedness == .signed) {
-                @compileError(bad_main_ret);
-            }
+        noreturn, u8 => {
             return root.main();
         },
-        .ErrorUnion => {
+        else => {
+            if (@typeInfo(ReturnType) != .ErrorUnion) @compileError(bad_main_ret);
+
             const result = root.main() catch |err| {
                 std.log.err("{s}", .{@errorName(err)});
                 if (@errorReturnTrace()) |trace| {
@@ -519,18 +517,13 @@ pub inline fn callMain() u8 {
                 }
                 return 1;
             };
-            switch (@typeInfo(@TypeOf(result))) {
-                .Void => return 0,
-                .Int => |info| {
-                    if (info.bits != 8 or info.signedness == .signed) {
-                        @compileError(bad_main_ret);
-                    }
-                    return result;
-                },
+
+            return switch (@TypeOf(result)) {
+                void => 0,
+                u8 => result,
                 else => @compileError(bad_main_ret),
-            }
+            };
         },
-        else => @compileError(bad_main_ret),
     }
 }