Replace Constant::partial_cmp

This commit is contained in:
Michael Wright 2018-06-19 07:37:09 +02:00
parent 7a32c28931
commit 0f83c68698
2 changed files with 24 additions and 28 deletions

View File

@ -122,21 +122,32 @@ fn hash<H>(&self, state: &mut H)
}
}
impl PartialOrd for Constant {
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
match (self, other) {
impl Constant {
pub fn partial_cmp(tcx: TyCtxt, cmp_type: &ty::TypeVariants, left: &Self, right: &Self) -> Option<Ordering> {
match (left, right) {
(&Constant::Str(ref ls), &Constant::Str(ref rs)) => Some(ls.cmp(rs)),
(&Constant::Char(ref l), &Constant::Char(ref r)) => Some(l.cmp(r)),
(&Constant::Int(l), &Constant::Int(r)) => Some(l.cmp(&r)),
(&Constant::Int(l), &Constant::Int(r)) => {
if let ty::TyInt(int_ty) = *cmp_type {
Some(sext(tcx, l, int_ty).cmp(&sext(tcx, r, int_ty)))
} else {
Some(l.cmp(&r))
}
},
(&Constant::F64(l), &Constant::F64(r)) => l.partial_cmp(&r),
(&Constant::F32(l), &Constant::F32(r)) => l.partial_cmp(&r),
(&Constant::Bool(ref l), &Constant::Bool(ref r)) => Some(l.cmp(r)),
(&Constant::Tuple(ref l), &Constant::Tuple(ref r)) | (&Constant::Vec(ref l), &Constant::Vec(ref r)) => {
l.partial_cmp(r)
},
(&Constant::Repeat(ref lv, ref ls), &Constant::Repeat(ref rv, ref rs)) => match lv.partial_cmp(rv) {
Some(Equal) => Some(ls.cmp(rs)),
x => x,
(&Constant::Tuple(ref l), &Constant::Tuple(ref r)) | (&Constant::Vec(ref l), &Constant::Vec(ref r)) => l
.iter()
.zip(r.iter())
.map(|(li, ri)| Constant::partial_cmp(tcx, cmp_type, li, ri))
.find(|r| r.map_or(true, |o| o != Ordering::Equal))
.unwrap_or_else(|| Some(l.len().cmp(&r.len()))),
(&Constant::Repeat(ref lv, ref ls), &Constant::Repeat(ref rv, ref rs)) => {
match Constant::partial_cmp(tcx, cmp_type, lv, rv) {
Some(Equal) => Some(ls.cmp(rs)),
x => x,
}
},
_ => None, // TODO: Are there any useful inter-type orderings?
}

View File

@ -1,9 +1,8 @@
use crate::consts::{constant_simple, Constant};
use crate::utils::{match_def_path, opt_def_id, paths, sext, span_lint};
use crate::utils::{match_def_path, opt_def_id, paths, span_lint};
use rustc::hir::*;
use rustc::lint::*;
use rustc::ty::{self, TyCtxt};
use std::cmp::{Ordering, PartialOrd};
use std::cmp::Ordering;
/// **What it does:** Checks for expressions where `std::cmp::min` and `max` are
/// used to clamp values, but switched so that the result is constant.
@ -43,7 +42,7 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
}
match (
outer_max,
const_partial_cmp(cx.tcx, &outer_c, &inner_c, &cx.tables.expr_ty(ie).sty),
Constant::partial_cmp(cx.tcx, &cx.tables.expr_ty(ie).sty, &outer_c, &inner_c),
) {
(_, None) | (MinMax::Max, Some(Ordering::Less)) | (MinMax::Min, Some(Ordering::Greater)) => (),
_ => {
@ -60,20 +59,6 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
}
}
// Constant::partial_cmp incorrectly orders signed integers
fn const_partial_cmp(tcx: TyCtxt, a: &Constant, b: &Constant, expr_ty: &ty::TypeVariants) -> Option<Ordering> {
match *expr_ty {
ty::TyInt(int_ty) => {
if let (&Constant::Int(a), &Constant::Int(b)) = (a, b) {
Some(sext(tcx, a, int_ty).cmp(&sext(tcx, b, int_ty)))
} else {
None
}
},
_ => a.partial_cmp(&b),
}
}
#[derive(PartialEq, Eq, Debug)]
enum MinMax {
Min,