std.meta: allow ArgsTuple to be used on functions with comptime parameters

any comptime parameter sets `.is_generic` to be true but in many cases these will still be discrete types available in `.params`

Author: nektro

lib/std/meta.zig

@@ -1037,14 +1037,12 @@ pub fn ArgsTuple(comptime Function: type) type {
         @compileError("ArgsTuple expects a function type");
 
     const function_info = info.Fn;
-    if (function_info.is_generic)
-        @compileError("Cannot create ArgsTuple for generic function");
     if (function_info.is_var_args)
         @compileError("Cannot create ArgsTuple for variadic function");
 
     var argument_field_list: [function_info.params.len]type = undefined;
     inline for (function_info.params, 0..) |arg, i| {
-        const T = arg.type.?;
+        const T = arg.type orelse @compileError("cannot create ArgsTuple for function with an 'anytype' parameter");
         argument_field_list[i] = T;
     }
 
@@ -1116,6 +1114,7 @@ test "ArgsTuple" {
     TupleTester.assertTuple(.{u32}, ArgsTuple(fn (a: u32) []const u8));
     TupleTester.assertTuple(.{ u32, f16 }, ArgsTuple(fn (a: u32, b: f16) noreturn));
     TupleTester.assertTuple(.{ u32, f16, []const u8, void }, ArgsTuple(fn (a: u32, b: f16, c: []const u8, void) noreturn));
+    TupleTester.assertTuple(.{u32}, ArgsTuple(fn (comptime a: u32) []const u8));
 }
 
 test "Tuple" {