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make all pattern bindings with the same name resolve to the first one
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This simplifies the code considerably, removing one of the
last uses of hygienic matching out of resolution.
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Ariel Ben-Yehuda authored and petrochenkov committed Jun 9, 2016
1 parent 392b6e7 commit e783a0a
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Showing 5 changed files with 22 additions and 77 deletions.
10 changes: 0 additions & 10 deletions src/librustc/hir/pat_util.rs
Original file line number Diff line number Diff line change
Expand Up @@ -53,16 +53,6 @@ impl<T: ExactSizeIterator> EnumerateAndAdjustIterator for T {
}
}

// This is used because same-named variables in alternative patterns need to
// use the NodeId of their namesake in the first pattern.
pub fn pat_id_map(pat: &hir::Pat) -> PatIdMap {
let mut map = FnvHashMap();
pat_bindings(pat, |_bm, p_id, _s, path1| {
map.insert(path1.node, p_id);
});
map
}

pub fn pat_is_refutable(dm: &DefMap, pat: &hir::Pat) -> bool {
match pat.node {
PatKind::Lit(_) | PatKind::Range(_, _) | PatKind::QPath(..) => true,
Expand Down
15 changes: 1 addition & 14 deletions src/librustc_mir/hair/cx/expr.rs
Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,6 @@
// except according to those terms.

use hair::*;
use rustc_data_structures::fnv::FnvHashMap;
use rustc_data_structures::indexed_vec::Idx;
use rustc_const_math::ConstInt;
use hair::cx::Cx;
Expand All @@ -20,7 +19,6 @@ use rustc::hir::def::Def;
use rustc::middle::const_val::ConstVal;
use rustc_const_eval as const_eval;
use rustc::middle::region::CodeExtent;
use rustc::hir::pat_util;
use rustc::ty::{self, VariantDef, Ty};
use rustc::ty::cast::CastKind as TyCastKind;
use rustc::mir::repr::*;
Expand Down Expand Up @@ -652,19 +650,8 @@ fn to_borrow_kind(m: hir::Mutability) -> BorrowKind {

fn convert_arm<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
arm: &'tcx hir::Arm) -> Arm<'tcx> {
let mut map;
let opt_map = if arm.pats.len() == 1 {
None
} else {
map = FnvHashMap();
pat_util::pat_bindings(&arm.pats[0], |_, p_id, _, path| {
map.insert(path.node, p_id);
});
Some(&map)
};

Arm {
patterns: arm.pats.iter().map(|p| cx.refutable_pat(opt_map, p)).collect(),
patterns: arm.pats.iter().map(|p| cx.refutable_pat(p)).collect(),
guard: arm.guard.to_ref(),
body: arm.body.to_ref(),
}
Expand Down
17 changes: 4 additions & 13 deletions src/librustc_mir/hair/cx/pattern.rs
Original file line number Diff line number Diff line change
Expand Up @@ -10,15 +10,13 @@

use hair::*;
use hair::cx::Cx;
use rustc_data_structures::fnv::FnvHashMap;
use rustc_data_structures::indexed_vec::Idx;
use rustc_const_eval as const_eval;
use rustc::hir::def::Def;
use rustc::hir::pat_util::{EnumerateAndAdjustIterator, pat_is_resolved_const};
use rustc::ty::{self, Ty};
use rustc::mir::repr::*;
use rustc::hir::{self, PatKind};
use syntax::ast;
use syntax::codemap::Span;
use syntax::ptr::P;

Expand All @@ -37,29 +35,25 @@ use syntax::ptr::P;
/// ```
struct PatCx<'patcx, 'cx: 'patcx, 'gcx: 'cx+'tcx, 'tcx: 'cx> {
cx: &'patcx mut Cx<'cx, 'gcx, 'tcx>,
binding_map: Option<&'patcx FnvHashMap<ast::Name, ast::NodeId>>,
}

impl<'cx, 'gcx, 'tcx> Cx<'cx, 'gcx, 'tcx> {
pub fn irrefutable_pat(&mut self, pat: &hir::Pat) -> Pattern<'tcx> {
PatCx::new(self, None).to_pattern(pat)
PatCx::new(self).to_pattern(pat)
}

pub fn refutable_pat(&mut self,
binding_map: Option<&FnvHashMap<ast::Name, ast::NodeId>>,
pat: &hir::Pat)
-> Pattern<'tcx> {
PatCx::new(self, binding_map).to_pattern(pat)
PatCx::new(self).to_pattern(pat)
}
}

impl<'patcx, 'cx, 'gcx, 'tcx> PatCx<'patcx, 'cx, 'gcx, 'tcx> {
fn new(cx: &'patcx mut Cx<'cx, 'gcx, 'tcx>,
binding_map: Option<&'patcx FnvHashMap<ast::Name, ast::NodeId>>)
fn new(cx: &'patcx mut Cx<'cx, 'gcx, 'tcx>)
-> PatCx<'patcx, 'cx, 'gcx, 'tcx> {
PatCx {
cx: cx,
binding_map: binding_map,
}
}

Expand Down Expand Up @@ -168,10 +162,7 @@ impl<'patcx, 'cx, 'gcx, 'tcx> PatCx<'patcx, 'cx, 'gcx, 'tcx> {
}

PatKind::Binding(bm, ref ident, ref sub) => {
let id = match self.binding_map {
None => pat.id,
Some(ref map) => map[&ident.node],
};
let id = self.cx.tcx.def_map.borrow()[&pat.id].full_def().var_id();
let var_ty = self.cx.tcx.node_id_to_type(pat.id);
let region = match var_ty.sty {
ty::TyRef(&r, _) => Some(r),
Expand Down
42 changes: 14 additions & 28 deletions src/librustc_typeck/check/_match.rs
Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,6 @@

use hir::def::Def;
use rustc::infer::{self, InferOk, TypeOrigin};
use hir::pat_util::{PatIdMap, pat_id_map};
use hir::pat_util::{EnumerateAndAdjustIterator, pat_is_resolved_const};
use rustc::ty::subst::Substs;
use rustc::ty::{self, Ty, TypeFoldable, LvaluePreference};
Expand All @@ -21,26 +20,13 @@ use session::Session;

use std::collections::hash_map::Entry::{Occupied, Vacant};
use std::cmp;
use std::ops::Deref;
use syntax::ast;
use syntax::codemap::{Span, Spanned};
use syntax::ptr::P;

use rustc::hir::{self, PatKind};
use rustc::hir::print as pprust;

pub struct PatCtxt<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
pub fcx: &'a FnCtxt<'a, 'gcx, 'tcx>,
pub map: PatIdMap,
}

impl<'a, 'gcx, 'tcx> Deref for PatCtxt<'a, 'gcx, 'tcx> {
type Target = FnCtxt<'a, 'gcx, 'tcx>;
fn deref(&self) -> &Self::Target {
self.fcx
}
}

// This function exists due to the warning "diagnostic code E0164 already used"
fn bad_struct_kind_err(sess: &Session, pat: &hir::Pat, path: &hir::Path, lint: bool) {
let name = pprust::path_to_string(path);
Expand All @@ -55,7 +41,7 @@ fn bad_struct_kind_err(sess: &Session, pat: &hir::Pat, path: &hir::Path, lint: b
}
}

impl<'a, 'gcx, 'tcx> PatCtxt<'a, 'gcx, 'tcx> {
impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
pub fn check_pat(&self, pat: &'gcx hir::Pat, expected: Ty<'tcx>) {
let tcx = self.tcx;

Expand Down Expand Up @@ -194,15 +180,19 @@ impl<'a, 'gcx, 'tcx> PatCtxt<'a, 'gcx, 'tcx> {

// if there are multiple arms, make sure they all agree on
// what the type of the binding `x` ought to be
if let Some(&canon_id) = self.map.get(&path.node) {
if canon_id != pat.id {
let ct = self.local_ty(pat.span, canon_id);
self.demand_eqtype(pat.span, ct, typ);
match tcx.def_map.borrow()[&pat.id].full_def() {
Def::Err => {}
Def::Local(_, var_id) => {
if var_id != pat.id {
let vt = self.local_ty(pat.span, var_id);
self.demand_eqtype(pat.span, vt, typ);
}
}
d => bug!("bad def for pattern binding `{:?}`", d)
}

if let Some(ref p) = *sub {
self.check_pat(&p, expected);
}
if let Some(ref p) = *sub {
self.check_pat(&p, expected);
}
}
PatKind::TupleStruct(ref path, ref subpats, ddpos) => {
Expand Down Expand Up @@ -476,12 +466,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
// Typecheck the patterns first, so that we get types for all the
// bindings.
for arm in arms {
let pcx = PatCtxt {
fcx: self,
map: pat_id_map(&arm.pats[0]),
};
for p in &arm.pats {
pcx.check_pat(&p, discrim_ty);
self.check_pat(&p, discrim_ty);
}
}

Expand Down Expand Up @@ -566,7 +552,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
}
}

impl<'a, 'gcx, 'tcx> PatCtxt<'a, 'gcx, 'tcx> {
impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
pub fn check_pat_struct(&self, pat: &'gcx hir::Pat,
path: &hir::Path, fields: &'gcx [Spanned<hir::FieldPat>],
etc: bool, expected: Ty<'tcx>) {
Expand Down
15 changes: 3 additions & 12 deletions src/librustc_typeck/check/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -81,14 +81,13 @@ pub use self::compare_method::{compare_impl_method, compare_const_impl};
use self::TupleArgumentsFlag::*;

use astconv::{AstConv, ast_region_to_region, PathParamMode};
use check::_match::PatCtxt;
use dep_graph::DepNode;
use fmt_macros::{Parser, Piece, Position};
use middle::cstore::LOCAL_CRATE;
use hir::def::{self, Def};
use hir::def_id::DefId;
use rustc::infer::{self, InferCtxt, InferOk, TypeOrigin, TypeTrace, type_variable};
use hir::pat_util::{self, pat_id_map};
use hir::pat_util::{self};
use rustc::ty::subst::{self, Subst, Substs, VecPerParamSpace, ParamSpace};
use rustc::traits::{self, ProjectionMode};
use rustc::ty::{GenericPredicates, TypeScheme};
Expand Down Expand Up @@ -672,11 +671,7 @@ fn check_fn<'a, 'gcx, 'tcx>(inherited: &'a Inherited<'a, 'gcx, 'tcx>,
});

// Check the pattern.
let pcx = PatCtxt {
fcx: &fcx,
map: pat_id_map(&input.pat),
};
pcx.check_pat(&input.pat, *arg_ty);
fcx.check_pat(&input.pat, *arg_ty);
}

visit.visit_block(body);
Expand Down Expand Up @@ -3786,11 +3781,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
}
}

let pcx = PatCtxt {
fcx: self,
map: pat_id_map(&local.pat),
};
pcx.check_pat(&local.pat, t);
self.check_pat(&local.pat, t);
let pat_ty = self.node_ty(local.pat.id);
if pat_ty.references_error() {
self.write_ty(local.id, pat_ty);
Expand Down

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