rust/src/libsyntax/show_span.rs

76 lines
1.7 KiB
Rust

//! Span debugger
//!
//! This module shows spans for all expressions in the crate
//! to help with compiler debugging.
use std::str::FromStr;
use crate::ast;
use crate::visit;
use crate::visit::Visitor;
enum Mode {
Expression,
Pattern,
Type,
}
impl FromStr for Mode {
type Err = ();
fn from_str(s: &str) -> Result<Mode, ()> {
let mode = match s {
"expr" => Mode::Expression,
"pat" => Mode::Pattern,
"ty" => Mode::Type,
_ => return Err(())
};
Ok(mode)
}
}
struct ShowSpanVisitor<'a> {
span_diagnostic: &'a errors::Handler,
mode: Mode,
}
impl<'a> Visitor<'a> for ShowSpanVisitor<'a> {
fn visit_expr(&mut self, e: &'a ast::Expr) {
if let Mode::Expression = self.mode {
self.span_diagnostic.span_warn(e.span, "expression");
}
visit::walk_expr(self, e);
}
fn visit_pat(&mut self, p: &'a ast::Pat) {
if let Mode::Pattern = self.mode {
self.span_diagnostic.span_warn(p.span, "pattern");
}
visit::walk_pat(self, p);
}
fn visit_ty(&mut self, t: &'a ast::Ty) {
if let Mode::Type = self.mode {
self.span_diagnostic.span_warn(t.span, "type");
}
visit::walk_ty(self, t);
}
fn visit_mac(&mut self, mac: &'a ast::Mac) {
visit::walk_mac(self, mac);
}
}
pub fn run(span_diagnostic: &errors::Handler,
mode: &str,
krate: &ast::Crate) {
let mode = match mode.parse().ok() {
Some(mode) => mode,
None => return
};
let mut v = ShowSpanVisitor {
span_diagnostic,
mode,
};
visit::walk_crate(&mut v, krate);
}