bjoernager/rust
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handle case of a variable not captured

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This commit is contained in:
Niko Matsakis 2021-11-04 21:26:47 -04:00
parent 76bc02715e
commit fc8113d04e
4 changed files with 117 additions and 8 deletions
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30
compiler/rustc_typeck/src/check/upvar.rs
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@ -90,10 +90,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
enum CapturesInfo {
/// We previously captured all of `x`, but now we capture some sub-path.
CapturingLess { source_expr: Option<hir::HirId>, var_name: String },
//CapturingNothing {
// // where the variable appears in the closure (but is not captured)
// use_span: Span,
//},
CapturingNothing {
// where the variable appears in the closure (but is not captured)
use_span: Span,
},
}
/// Reasons that we might issue a migration warning.
@ -758,6 +758,12 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
captured_name,
));
}
CapturesInfo::CapturingNothing { use_span } => {
diagnostics_builder.span_label(*use_span, format!("in Rust 2018, this causes the closure to capture `{}`, but in Rust 2021, it has no effect",
self.tcx.hir().name(*var_hir_id),
));
}
_ => { }
}
@ -773,6 +779,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
captured_name,
));
}
CapturesInfo::CapturingNothing { use_span: _ } => {
diagnostics_builder.span_label(drop_location_span, format!("in Rust 2018, `{v}` is dropped here along with the closure, but in Rust 2021 `{v}` is not part of the closure",
v = self.tcx.hir().name(*var_hir_id),
));
}
}
}
@ -787,6 +798,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
p = captured_name,
));
}
// Cannot happen: if we don't capture a variable, we impl strictly more traits
CapturesInfo::CapturingNothing { use_span } => span_bug!(*use_span, "missing trait from not capturing something"),
}
}
}
@ -1051,10 +1065,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
match closure_clause {
// Only migrate if closure is a move closure
hir::CaptureBy::Value => {
let diagnostics_info = FxHashSet::default();
//diagnostics_info.insert(CapturesInfo::CapturingNothing);
//let upvars = self.tcx.upvars_mentioned(closure_def_id).expect("must be an upvar");
//let _span = upvars[&var_hir_id];
let mut diagnostics_info = FxHashSet::default();
let upvars = self.tcx.upvars_mentioned(closure_def_id).expect("must be an upvar");
let upvar = upvars[&var_hir_id];
diagnostics_info.insert(CapturesInfo::CapturingNothing { use_span: upvar.span });
return Some(diagnostics_info);
}
hir::CaptureBy::Ref => {}