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// These are tests for syntax that is accepted by the Rust parser but
// unconditionally rejected semantically after macro expansion. Attribute macros
// are permitted to accept such syntax as long as they replace it with something
// that makes sense to Rust.
//
// We also inspect some of the spans to verify the syntax is not triggering the
// lossy string reparse hack (https://github.com/rust-lang/rust/issues/43081).
#![feature(proc_macro_span)]
extern crate proc_macro;
use proc_macro::{token_stream, Delimiter, TokenStream, TokenTree};
use std::path::Component;
// unsafe mod m {
// pub unsafe mod inner;
// }
#[proc_macro_attribute]
pub fn expect_unsafe_mod(_attrs: TokenStream, input: TokenStream) -> TokenStream {
let tokens = &mut input.into_iter();
expect(tokens, "unsafe");
expect(tokens, "mod");
expect(tokens, "m");
let tokens = &mut expect_brace(tokens);
expect(tokens, "pub");
expect(tokens, "unsafe");
expect(tokens, "mod");
let ident = expect(tokens, "inner");
expect(tokens, ";");
check_useful_span(ident, "unsafe-mod.rs");
TokenStream::new()
}
// unsafe extern {
// type T;
// }
#[proc_macro_attribute]
pub fn expect_unsafe_foreign_mod(_attrs: TokenStream, input: TokenStream) -> TokenStream {
let tokens = &mut input.into_iter();
expect(tokens, "unsafe");
expect(tokens, "extern");
let tokens = &mut expect_brace(tokens);
expect(tokens, "type");
let ident = expect(tokens, "T");
expect(tokens, ";");
check_useful_span(ident, "unsafe-foreign-mod.rs");
TokenStream::new()
}
// unsafe extern "C++" {}
#[proc_macro_attribute]
pub fn expect_unsafe_extern_cpp_mod(_attrs: TokenStream, input: TokenStream) -> TokenStream {
let tokens = &mut input.into_iter();
expect(tokens, "unsafe");
expect(tokens, "extern");
let abi = expect(tokens, "\"C++\"");
expect_brace(tokens);
check_useful_span(abi, "unsafe-foreign-mod.rs");
TokenStream::new()
}
fn expect(tokens: &mut token_stream::IntoIter, expected: &str) -> TokenTree {
match tokens.next() {
Some(token) if token.to_string() == expected => token,
wrong => panic!("unexpected token: {:?}, expected `{}`", wrong, expected),
}
}
fn expect_brace(tokens: &mut token_stream::IntoIter) -> token_stream::IntoIter {
match tokens.next() {
Some(TokenTree::Group(group)) if group.delimiter() == Delimiter::Brace => {
group.stream().into_iter()
}
wrong => panic!("unexpected token: {:?}, expected `{{`", wrong),
}
}
fn check_useful_span(token: TokenTree, expected_filename: &str) {
let span = token.span();
assert!(span.column() < span.end().column());
let source_path = span.source_file().path();
let filename = source_path.components().last().unwrap();
assert_eq!(filename, Component::Normal(expected_filename.as_ref()));
}
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