tests/ui/proc-macro/allowed-attr-stmt-expr.rs

   1 // aux-build:attr-stmt-expr.rs
   2 // aux-build:test-macros.rs
   3 // compile-flags: -Z span-debug
   4 // check-pass
   5
   6 #![feature(proc_macro_hygiene)]
   7 #![feature(stmt_expr_attributes)]
   8 #![feature(rustc_attrs)]
   9 #![allow(dead_code)]
  10
  11 #![no_std] // Don't load unnecessary hygiene information from std
  12 extern crate std;
  13
  14 extern crate attr_stmt_expr;
  15 extern crate test_macros;
  16 use attr_stmt_expr::{expect_let, expect_my_macro_stmt, expect_expr, expect_my_macro_expr};
  17 use test_macros::print_attr;
  18
  19 // We don't use `std::println` so that we avoid loading hygiene
  20 // information from libstd, which would affect the SyntaxContext ids
  21 macro_rules! my_macro {
  22     ($($tt:tt)*) => { () }
  23 }
  24
  25
  26 fn print_str(string: &'static str) {
  27     // macros are handled a bit differently
  28     #[expect_my_macro_expr]
  29     my_macro!("{}", string)
  30 }
  31
  32 macro_rules! make_stmt {
  33     ($stmt:stmt) => {
  34         #[print_attr]
  35         #[rustc_dummy]
  36         $stmt; // This semicolon is *not* passed to the macro,
  37                // since `$stmt` is already a statement.
  38     }
  39 }
  40
  41 macro_rules! second_make_stmt {
  42     ($stmt:stmt) => {
  43         make_stmt!($stmt);
  44     }
  45 }
  46
  47 // The macro will see a semicolon here
  48 #[print_attr]
  49 struct ItemWithSemi;
  50
  51
  52 fn main() {
  53     make_stmt!(struct Foo {});
  54
  55     #[print_attr]
  56     #[expect_let]
  57     let string = "Hello, world!";
  58
  59     #[print_attr]
  60     #[expect_my_macro_stmt]
  61     my_macro!("{}", string);
  62
  63     #[print_attr]
  64     second_make_stmt!(#[allow(dead_code)] struct Bar {});
  65
  66     #[print_attr]
  67     #[rustc_dummy]
  68     struct Other {};
  69
  70     // The macro also sees a semicolon,
  71     // for consistency with the `ItemWithSemi` case above.
  72     #[print_attr]
  73     #[rustc_dummy]
  74     struct NonBracedStruct;
  75
  76     #[expect_expr]
  77     print_str("string")
  78 }