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#![feature(rustc_private)]
extern crate rustc_ast;
extern crate rustc_driver;
extern crate rustc_errors;
extern crate rustc_parse;
extern crate rustc_session;
extern crate rustc_span;
use rustc_ast::ast::{DUMMY_NODE_ID, Expr};
use rustc_ast::mut_visit::MutVisitor;
use rustc_ast::node_id::NodeId;
use rustc_ast::ptr::P;
use rustc_ast::token;
use rustc_errors::Diag;
use rustc_parse::parser::Recovery;
use rustc_session::parse::ParseSess;
use rustc_span::{DUMMY_SP, FileName, Span};
pub fn parse_expr(psess: &ParseSess, source_code: &str) -> Option<P<Expr>> {
let parser = rustc_parse::unwrap_or_emit_fatal(rustc_parse::new_parser_from_source_str(
psess,
FileName::anon_source_code(source_code),
source_code.to_owned(),
));
let mut parser = parser.recovery(Recovery::Forbidden);
let mut expr = parser.parse_expr().map_err(Diag::cancel).ok()?;
if parser.token != token::Eof {
return None;
}
Normalize.visit_expr(&mut expr);
Some(expr)
}
// Erase Span information that could distinguish between identical expressions
// parsed from different source strings.
struct Normalize;
impl MutVisitor for Normalize {
const VISIT_TOKENS: bool = true;
fn visit_id(&mut self, id: &mut NodeId) {
*id = DUMMY_NODE_ID;
}
fn visit_span(&mut self, span: &mut Span) {
*span = DUMMY_SP;
}
}
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