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qualify_consts: extract check_short_circuiting_in_const_local.

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This commit is contained in:
Mazdak Farrokhzad 2019-08-29 09:10:26 +02:00
parent 8f184b369d
commit b6360fbc4c
1 changed files with 35 additions and 31 deletions
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66
src/librustc_mir/transform/qualify_consts.rs
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@ -1655,37 +1655,8 @@ impl<'tcx> MirPass<'tcx> for QualifyAndPromoteConstants<'tcx> {
_ => None,
};
if !body.control_flow_destroyed.is_empty() {
let mut locals = body.vars_iter();
if let Some(local) = locals.next() {
let span = body.local_decls[local].source_info.span;
let mut error = tcx.sess.struct_span_err(
span,
&format!(
"new features like let bindings are not permitted in {}s \
which also use short circuiting operators",
mode,
),
);
for (span, kind) in body.control_flow_destroyed.iter() {
error.span_note(
*span,
&format!("use of {} here does not actually short circuit due to \
the const evaluator presently not being able to do control flow. \
See https://github.com/rust-lang/rust/issues/49146 for more \
information.", kind),
);
}
for local in locals {
let span = body.local_decls[local].source_info.span;
error.span_note(
span,
"more locals defined here",
);
}
error.emit();
}
}
check_short_circuiting_in_const_local(tcx, body, mode);
let promoted_temps = match mode {
// Already computed by `mir_const_qualif`.
Mode::Const => const_promoted_temps.unwrap(),
@ -1762,6 +1733,39 @@ fn determine_mode(tcx: TyCtxt<'_>, hir_id: HirId, def_id: DefId) -> Mode {
}
}
fn check_short_circuiting_in_const_local(tcx: TyCtxt<'_>, body: &mut Body<'tcx>, mode: Mode) {
if body.control_flow_destroyed.is_empty() {
return;
}
let mut locals = body.vars_iter();
if let Some(local) = locals.next() {
let span = body.local_decls[local].source_info.span;
let mut error = tcx.sess.struct_span_err(
span,
&format!(
"new features like let bindings are not permitted in {}s \
which also use short circuiting operators",
mode,
),
);
for (span, kind) in body.control_flow_destroyed.iter() {
error.span_note(
*span,
&format!("use of {} here does not actually short circuit due to \
the const evaluator presently not being able to do control flow. \
See https://github.com/rust-lang/rust/issues/49146 for more \
information.", kind),
);
}
for local in locals {
let span = body.local_decls[local].source_info.span;
error.span_note(span, "more locals defined here");
}
error.emit();
}
}
fn args_required_const(tcx: TyCtxt<'_>, def_id: DefId) -> Option<FxHashSet<usize>> {
let attrs = tcx.get_attrs(def_id);
let attr = attrs.iter().find(|a| a.check_name(sym::rustc_args_required_const))?;