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Coalesce branches

Move a bunch of branches together into one if block, for easier reading.

Resolve comments

Attempt to make some branches unreachable [tmp]

Revert unreachable branches
This commit is contained in:
kadmin 2022-05-19 18:53:01 +00:00
parent edae6edd32
commit ee8efc5c4a
2 changed files with 135 additions and 139 deletions

View file

@ -21,6 +21,7 @@
#![feature(label_break_value)] #![feature(label_break_value)]
#![feature(let_chains)] #![feature(let_chains)]
#![feature(let_else)] #![feature(let_else)]
#![feature(if_let_guard)]
#![feature(never_type)] #![feature(never_type)]
#![recursion_limit = "512"] // For rustdoc #![recursion_limit = "512"] // For rustdoc

View file

@ -39,9 +39,7 @@ pub fn is_const_evaluatable<'cx, 'tcx>(
let tcx = infcx.tcx; let tcx = infcx.tcx;
if tcx.features().generic_const_exprs { if tcx.features().generic_const_exprs {
match AbstractConst::new(tcx, uv)? { if let Some(ct) = AbstractConst::new(tcx, uv)? {
// We are looking at a generic abstract constant.
Some(ct) => {
if satisfied_from_param_env(tcx, ct, param_env)? { if satisfied_from_param_env(tcx, ct, param_env)? {
return Ok(()); return Ok(());
} }
@ -93,37 +91,32 @@ pub fn is_const_evaluatable<'cx, 'tcx>(
FailureKind::MentionsParam => { FailureKind::MentionsParam => {
return Err(NotConstEvaluatable::MentionsParam); return Err(NotConstEvaluatable::MentionsParam);
} }
FailureKind::Concrete => { // returned below
// Dealt with below by the same code which handles this FailureKind::Concrete => {}
// without the feature gate.
} }
} }
let concrete = infcx.const_eval_resolve(param_env, uv.expand(), Some(span));
match concrete {
Err(ErrorHandled::TooGeneric) => Err(if !uv.has_infer_types_or_consts() {
infcx
.tcx
.sess
.delay_span_bug(span, &format!("unexpected `TooGeneric` for {:?}", uv));
NotConstEvaluatable::MentionsParam
} else {
NotConstEvaluatable::MentionsInfer
}),
Err(ErrorHandled::Linted) => {
let reported = infcx
.tcx
.sess
.delay_span_bug(span, "constant in type had error reported as lint");
Err(NotConstEvaluatable::Error(reported))
} }
None => { Err(ErrorHandled::Reported(e)) => Err(NotConstEvaluatable::Error(e)),
// If we are dealing with a concrete constant, we can Ok(_) => Ok(()),
// reuse the old code path and try to evaluate
// the constant.
} }
} } else {
}
let future_compat_lint = || {
if tcx.features().generic_const_exprs {
return;
}
if let Some(local_def_id) = uv.def.did.as_local() {
infcx.tcx.struct_span_lint_hir(
lint::builtin::CONST_EVALUATABLE_UNCHECKED,
infcx.tcx.hir().local_def_id_to_hir_id(local_def_id),
span,
|err| {
err.build("cannot use constants which depend on generic parameters in types")
.emit();
},
);
}
};
// FIXME: We should only try to evaluate a given constant here if it is fully concrete // FIXME: We should only try to evaluate a given constant here if it is fully concrete
// as we don't want to allow things like `[u8; std::mem::size_of::<*mut T>()]`. // as we don't want to allow things like `[u8; std::mem::size_of::<*mut T>()]`.
// //
@ -134,29 +127,13 @@ pub fn is_const_evaluatable<'cx, 'tcx>(
// See #74595 for more details about this. // See #74595 for more details about this.
let concrete = infcx.const_eval_resolve(param_env, uv.expand(), Some(span)); let concrete = infcx.const_eval_resolve(param_env, uv.expand(), Some(span));
if concrete.is_ok() && uv.substs.has_param_types_or_consts() { match concrete {
match infcx.tcx.def_kind(uv.def.did) {
DefKind::AnonConst | DefKind::InlineConst => {
let mir_body = infcx.tcx.mir_for_ctfe_opt_const_arg(uv.def);
if mir_body.is_polymorphic {
future_compat_lint();
}
}
_ => future_compat_lint(),
}
}
// If we're evaluating a foreign constant, under a nightly compiler without generic // If we're evaluating a foreign constant, under a nightly compiler without generic
// const exprs, AND it would've passed if that expression had been evaluated with // const exprs, AND it would've passed if that expression had been evaluated with
// generic const exprs, then suggest using generic const exprs. // generic const exprs, then suggest using generic const exprs.
if concrete.is_err() Err(_) if tcx.sess.is_nightly_build()
&& tcx.sess.is_nightly_build()
&& !uv.def.did.is_local()
&& !tcx.features().generic_const_exprs
&& let Ok(Some(ct)) = AbstractConst::new(tcx, uv) && let Ok(Some(ct)) = AbstractConst::new(tcx, uv)
&& satisfied_from_param_env(tcx, ct, param_env) == Ok(true) && satisfied_from_param_env(tcx, ct, param_env) == Ok(true) => {
{
tcx.sess tcx.sess
.struct_span_fatal( .struct_span_fatal(
// Slightly better span than just using `span` alone // Slightly better span than just using `span` alone
@ -173,11 +150,10 @@ pub fn is_const_evaluatable<'cx, 'tcx>(
.emit() .emit()
} }
debug!(?concrete, "is_const_evaluatable"); Err(ErrorHandled::TooGeneric) => Err(if uv.has_infer_types_or_consts() {
match concrete { NotConstEvaluatable::MentionsInfer
Err(ErrorHandled::TooGeneric) => Err(match uv.has_infer_types_or_consts() { } else {
true => NotConstEvaluatable::MentionsInfer, NotConstEvaluatable::MentionsParam
false => NotConstEvaluatable::MentionsParam,
}), }),
Err(ErrorHandled::Linted) => { Err(ErrorHandled::Linted) => {
let reported = let reported =
@ -185,7 +161,26 @@ pub fn is_const_evaluatable<'cx, 'tcx>(
Err(NotConstEvaluatable::Error(reported)) Err(NotConstEvaluatable::Error(reported))
} }
Err(ErrorHandled::Reported(e)) => Err(NotConstEvaluatable::Error(e)), Err(ErrorHandled::Reported(e)) => Err(NotConstEvaluatable::Error(e)),
Ok(_) => Ok(()), Ok(_) => {
if uv.substs.has_param_types_or_consts() {
assert!(matches!(infcx.tcx.def_kind(uv.def.did), DefKind::AnonConst));
let mir_body = infcx.tcx.mir_for_ctfe_opt_const_arg(uv.def);
if mir_body.is_polymorphic {
let Some(local_def_id) = uv.def.did.as_local() else { return Ok(()) };
tcx.struct_span_lint_hir(
lint::builtin::CONST_EVALUATABLE_UNCHECKED,
tcx.hir().local_def_id_to_hir_id(local_def_id),
span,
|err| {
err.build("cannot use constants which depend on generic parameters in types").emit();
})
}
}
Ok(())
},
}
} }
} }