struct_, union_, or enum_, as in C.struct_stat.

The size of any C type T is available as C.sizeof_T, as in
C.sizeof_struct_stat.

A C function may be declared in the Go file with a parameter type of
the special name _GoString_. This function may be called with an
ordinary Go string value. The string length, and a pointer to the
string contents, may be accessed by calling the C functions

// For slices, clear sets all elements up to the length of the slice
// to the zero value of the respective element type. If the argument
// type is a type parameter, the type parameter's type set must
// contain only map or slice types, and clear performs the operation
// implied by the type argument.
func clear[T ~[]Type | ~map[Type]Type1](t T)

			for i := 0; i < targs.Len(); i++ {
				if i > 0 {
					buf.WriteString(", ")
				}
				w.writeType(buf, targs.At(i))
			}
			buf.WriteByte(']')
		}

	case *types.TypeParam:
		// Type parameter names may change, so use a placeholder instead.
		fmt.Fprintf(buf, "$%d", typ.Index())

	default:
		panic(fmt.Sprintf("unknown type %T", typ))
	}
}