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use rustc_ast::ptr::P;
use rustc_ast::tokenstream::TokenStream;
use rustc_ast::{token, Expr, ExprKind, Ty};
use rustc_errors::PResult;
use rustc_expand::base::{self, DummyResult, ExtCtxt, MacEager};
use rustc_span::Span;
pub fn expand_type_ascribe(
cx: &mut ExtCtxt<'_>,
span: Span,
tts: TokenStream,
) -> Box<dyn base::MacResult + 'static> {
let (expr, ty) = match parse_ascribe(cx, tts) {
Ok(parsed) => parsed,
Err(mut err) => {
err.emit();
return DummyResult::any(span);
}
};
let asc_expr = cx.expr(span, ExprKind::Type(expr, ty));
return MacEager::expr(asc_expr);
}
fn parse_ascribe<'a>(cx: &mut ExtCtxt<'a>, stream: TokenStream) -> PResult<'a, (P<Expr>, P<Ty>)> {
let mut parser = cx.new_parser_from_tts(stream);
let expr = parser.parse_expr()?;
parser.expect(&token::Comma)?;
let ty = parser.parse_ty()?;
Ok((expr, ty))
}
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