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Auto merge of #88271 - sexxi-goose:liveness, r=nikomatsakis

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2229: Consider varaiables mentioned in closure as used

Fixes: https://github.com/rust-lang/project-rfc-2229/issues/57

r? `@nikomatsakis`
This commit is contained in:
bors 2021-08-24 23:30:44 +00:00
commit faa0a10406
5 changed files with 10 additions and 63 deletions
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36
compiler/rustc_passes/src/liveness.rs
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@ -337,8 +337,8 @@ impl<'tcx> Visitor<'tcx> for IrMaps<'tcx> {
return;
}
if let Some(captures) = maps.tcx.typeck(local_def_id).closure_min_captures.get(&def_id) {
for &var_hir_id in captures.keys() {
if let Some(upvars) = maps.tcx.upvars_mentioned(def_id) {
for &var_hir_id in upvars.keys() {
let var_name = maps.tcx.hir().name(var_hir_id);
maps.add_variable(Upvar(var_hir_id, var_name));
}
@ -405,21 +405,14 @@ impl<'tcx> Visitor<'tcx> for IrMaps<'tcx> {
// breaks or continues)
self.add_live_node_for_node(expr.hir_id, ExprNode(expr.span, expr.hir_id));
// Make a live_node for each captured variable, with the span
// Make a live_node for each mentioned variable, with the span
// being the location that the variable is used. This results
// in better error messages than just pointing at the closure
// construction site.
let mut call_caps = Vec::new();
let closure_def_id = self.tcx.hir().local_def_id(expr.hir_id);
if let Some(captures) = self
.tcx
.typeck(closure_def_id)
.closure_min_captures
.get(&closure_def_id.to_def_id())
{
// If closure_min_captures is Some, upvars_mentioned must also be Some
let upvars = self.tcx.upvars_mentioned(closure_def_id).unwrap();
call_caps.extend(captures.keys().map(|var_id| {
if let Some(upvars) = self.tcx.upvars_mentioned(closure_def_id) {
call_caps.extend(upvars.keys().map(|var_id| {
let upvar = upvars[var_id];
let upvar_ln = self.add_live_node(UpvarNode(upvar.span));
CaptureInfo { ln: upvar_ln, var_hid: *var_id }
@ -494,7 +487,6 @@ struct Liveness<'a, 'tcx> {
ir: &'a mut IrMaps<'tcx>,
typeck_results: &'a ty::TypeckResults<'tcx>,
param_env: ty::ParamEnv<'tcx>,
upvars: Option<&'tcx FxIndexMap<hir::HirId, hir::Upvar>>,
closure_min_captures: Option<&'tcx RootVariableMinCaptureList<'tcx>>,
successors: IndexVec<LiveNode, Option<LiveNode>>,
rwu_table: rwu_table::RWUTable,
@ -518,7 +510,6 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
fn new(ir: &'a mut IrMaps<'tcx>, body_owner: LocalDefId) -> Liveness<'a, 'tcx> {
let typeck_results = ir.tcx.typeck(body_owner);
let param_env = ir.tcx.param_env(body_owner);
let upvars = ir.tcx.upvars_mentioned(body_owner);
let closure_min_captures = typeck_results.closure_min_captures.get(&body_owner.to_def_id());
let closure_ln = ir.add_live_node(ClosureNode);
let exit_ln = ir.add_live_node(ExitNode);
@ -530,7 +521,6 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
ir,
typeck_results,
param_env,
upvars,
closure_min_captures,
successors: IndexVec::from_elem_n(None, num_live_nodes),
rwu_table: rwu_table::RWUTable::new(num_live_nodes, num_vars),
@ -1215,21 +1205,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
acc: u32,
) -> LiveNode {
match path.res {
Res::Local(hid) => {
let in_upvars = self.upvars.map_or(false, |u| u.contains_key(&hid));
let in_captures = self.closure_min_captures.map_or(false, |c| c.contains_key(&hid));
match (in_upvars, in_captures) {
(false, _) | (true, true) => self.access_var(hir_id, hid, succ, acc, path.span),
(true, false) => {
// This case is possible when with RFC-2229, a wild pattern
// is used within a closure.
// eg: `let _ = x`. The closure doesn't capture x here,
// even though it's mentioned in the closure.
succ
}
}
}
Res::Local(hid) => self.access_var(hir_id, hid, succ, acc, path.span),
_ => succ,
}
}