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 @@ impl Hash for Constant {
} }
} }
impl PartialOrd for Constant { impl Constant {
fn partial_cmp(&self, other: &Self) -> Option<Ordering> { pub fn partial_cmp(tcx: TyCtxt, cmp_type: &ty::TypeVariants, left: &Self, right: &Self) -> Option<Ordering> {
match (self, other) { match (left, right) {
(&Constant::Str(ref ls), &Constant::Str(ref rs)) => Some(ls.cmp(rs)), (&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::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::F64(l), &Constant::F64(r)) => l.partial_cmp(&r),
(&Constant::F32(l), &Constant::F32(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::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)) => { (&Constant::Tuple(ref l), &Constant::Tuple(ref r)) | (&Constant::Vec(ref l), &Constant::Vec(ref r)) => l
l.partial_cmp(r) .iter()
}, .zip(r.iter())
(&Constant::Repeat(ref lv, ref ls), &Constant::Repeat(ref rv, ref rs)) => match lv.partial_cmp(rv) { .map(|(li, ri)| Constant::partial_cmp(tcx, cmp_type, li, ri))
Some(Equal) => Some(ls.cmp(rs)), .find(|r| r.map_or(true, |o| o != Ordering::Equal))
x => x, .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? _ => None, // TODO: Are there any useful inter-type orderings?
} }

View File

@@ -1,9 +1,8 @@
use crate::consts::{constant_simple, Constant}; 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::hir::*;
use rustc::lint::*; use rustc::lint::*;
use rustc::ty::{self, TyCtxt}; use std::cmp::Ordering;
use std::cmp::{Ordering, PartialOrd};
/// **What it does:** Checks for expressions where `std::cmp::min` and `max` are /// **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. /// used to clamp values, but switched so that the result is constant.
@@ -43,7 +42,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MinMaxPass {
} }
match ( match (
outer_max, 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)) => (), (_, None) | (MinMax::Max, Some(Ordering::Less)) | (MinMax::Min, Some(Ordering::Greater)) => (),
_ => { _ => {
@@ -60,20 +59,6 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MinMaxPass {
} }
} }
// 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)] #[derive(PartialEq, Eq, Debug)]
enum MinMax { enum MinMax {
Min, Min,