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use rustc_ast as ast;
use rustc_ast::tokenstream::TokenStream;
use rustc_expand::base::{self, DummyResult};
use rustc_session::errors::report_lit_error;
use rustc_span::symbol::Symbol;
pub fn expand_concat(
cx: &mut base::ExtCtxt<'_>,
sp: rustc_span::Span,
tts: TokenStream,
) -> Box<dyn base::MacResult + 'static> {
let Some(es) = base::get_exprs_from_tts(cx, tts) else {
return DummyResult::any(sp);
};
let mut accumulator = String::new();
let mut missing_literal = vec![];
let mut has_errors = false;
for e in es {
match e.kind {
ast::ExprKind::Lit(token_lit) => match ast::LitKind::from_token_lit(token_lit) {
Ok(ast::LitKind::Str(s, _) | ast::LitKind::Float(s, _)) => {
accumulator.push_str(s.as_str());
}
Ok(ast::LitKind::Char(c)) => {
accumulator.push(c);
}
Ok(ast::LitKind::Int(i, _)) => {
accumulator.push_str(&i.to_string());
}
Ok(ast::LitKind::Bool(b)) => {
accumulator.push_str(&b.to_string());
}
Ok(ast::LitKind::Byte(..) | ast::LitKind::ByteStr(..)) => {
cx.span_err(e.span, "cannot concatenate a byte string literal");
has_errors = true;
}
Ok(ast::LitKind::Err) => {
has_errors = true;
}
Err(err) => {
report_lit_error(&cx.sess.parse_sess, err, token_lit, e.span);
has_errors = true;
}
},
ast::ExprKind::IncludedBytes(..) => {
cx.span_err(e.span, "cannot concatenate a byte string literal")
}
ast::ExprKind::Err => {
has_errors = true;
}
_ => {
missing_literal.push(e.span);
}
}
}
if !missing_literal.is_empty() {
let mut err = cx.struct_span_err(missing_literal, "expected a literal");
err.note("only literals (like `\"foo\"`, `42` and `3.14`) can be passed to `concat!()`");
err.emit();
return DummyResult::any(sp);
} else if has_errors {
return DummyResult::any(sp);
}
let sp = cx.with_def_site_ctxt(sp);
base::MacEager::expr(cx.expr_str(sp, Symbol::intern(&accumulator)))
}
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