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librustc error_reporting.rs cleanup. #39977

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merged 8 commits into from
Feb 28, 2017
Merged

librustc error_reporting.rs cleanup. #39977

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7e0c3de
Remove `else`, unindent.
frewsxcv Feb 19, 2017
de2f7e1
Rewrite `match` to use combinators.
frewsxcv Feb 19, 2017
83fe48d
Remove `else`, unindent.
frewsxcv Feb 19, 2017
a97aed7
Remove unnecessary logic when finding simpilar `impl` candidates.
frewsxcv Feb 19, 2017
2436d73
Extract out error message generation.
frewsxcv Feb 19, 2017
10639d7
Add early return, remove `else`, unindent.
frewsxcv Feb 19, 2017
23d9211
Flatten `for` loop using iterator combinators.
frewsxcv Feb 19, 2017
a754ea6
Move `TraitRef` `impl` next to `struct` definition.
frewsxcv Feb 20, 2017
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100 changes: 18 additions & 82 deletions src/librustc/traits/error_reporting.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -21,7 +21,6 @@ use super::{
SelectionContext,
SelectionError,
ObjectSafetyViolation,
MethodViolationCode,
};

use fmt_macros::{Parser, Piece, Position};
Expand Down Expand Up @@ -267,8 +266,12 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {

let span = obligation.cause.span;
let mut report = None;
for item in self.tcx.get_attrs(def_id).iter() {
if item.check_name("rustc_on_unimplemented") {
if let Some(item) = self.tcx
.get_attrs(def_id)
.into_iter()
.filter(|a| a.check_name("rustc_on_unimplemented"))
.next()
{
let err_sp = item.meta().span.substitute_dummy(span);
let trait_str = self.tcx.item_path_str(trait_ref.def_id);
if let Some(istring) = item.value_str() {
Expand Down Expand Up @@ -321,8 +324,6 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
eg `#[rustc_on_unimplemented = \"foo\"]`",
trait_str);
}
break;
}
}
report
}
Expand Down Expand Up @@ -359,34 +360,9 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
}

fn report_similar_impl_candidates(&self,
trait_ref: ty::PolyTraitRef<'tcx>,
impl_candidates: Vec<ty::TraitRef<'tcx>>,
err: &mut DiagnosticBuilder)
{
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Was all of this duplicated from find_similar_impl_candidates? 😆

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Yeeeppppppp

let simp = fast_reject::simplify_type(self.tcx,
trait_ref.skip_binder().self_ty(),
true);
let mut impl_candidates = Vec::new();
let trait_def = self.tcx.lookup_trait_def(trait_ref.def_id());

match simp {
Some(simp) => trait_def.for_each_impl(self.tcx, |def_id| {
let imp = self.tcx.impl_trait_ref(def_id).unwrap();
let imp_simp = fast_reject::simplify_type(self.tcx,
imp.self_ty(),
true);
if let Some(imp_simp) = imp_simp {
if simp != imp_simp {
return;
}
}
impl_candidates.push(imp);
}),
None => trait_def.for_each_impl(self.tcx, |def_id| {
impl_candidates.push(
self.tcx.impl_trait_ref(def_id).unwrap());
})
};

if impl_candidates.is_empty() {
return;
}
Expand Down Expand Up @@ -525,24 +501,20 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
lint_id)
.emit();
return;
} else {
}
match obligation.predicate {
ty::Predicate::Trait(ref trait_predicate) => {
let trait_predicate =
self.resolve_type_vars_if_possible(trait_predicate);

if self.tcx.sess.has_errors() && trait_predicate.references_error() {
return;
} else {
let trait_ref = trait_predicate.to_poly_trait_ref();
let (post_message, pre_message) = match self.get_parent_trait_ref(
&obligation.cause.code)
{
Some(t) => {
(format!(" in `{}`", t), format!("within `{}`, ", t))
}
None => (String::new(), String::new()),
};
let trait_ref = trait_predicate.to_poly_trait_ref();
let (post_message, pre_message) =
self.get_parent_trait_ref(&obligation.cause.code)
.map(|t| (format!(" in `{}`", t), format!("within `{}`, ", t)))
.unwrap_or((String::new(), String::new()));
let mut err = struct_span_err!(
self.tcx.sess,
span,
Expand Down Expand Up @@ -578,15 +550,11 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
} else {
// If we can't show anything useful, try to find
// similar impls.
let impl_candidates =
self.find_similar_impl_candidates(trait_ref);
if impl_candidates.len() > 0 {
self.report_similar_impl_candidates(trait_ref, &mut err);
}
let impl_candidates = self.find_similar_impl_candidates(trait_ref);
self.report_similar_impl_candidates(impl_candidates, &mut err);
}
err
}
}

ty::Predicate::Equate(ref predicate) => {
let predicate = self.resolve_type_vars_if_possible(predicate);
Expand Down Expand Up @@ -648,7 +616,6 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
}
}
}
}

OutputTypeParameterMismatch(ref expected_trait_ref, ref actual_trait_ref, ref e) => {
let expected_trait_ref = self.resolve_type_vars_if_possible(&*expected_trait_ref);
Expand Down Expand Up @@ -713,38 +680,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
if !reported_violations.insert(violation.clone()) {
continue;
}
let buf;
let note = match violation {
ObjectSafetyViolation::SizedSelf => {
"the trait cannot require that `Self : Sized`"
}

ObjectSafetyViolation::SupertraitSelf => {
"the trait cannot use `Self` as a type parameter \
in the supertrait listing"
}

ObjectSafetyViolation::Method(name,
MethodViolationCode::StaticMethod) => {
buf = format!("method `{}` has no receiver", name);
&buf
}

ObjectSafetyViolation::Method(name,
MethodViolationCode::ReferencesSelf) => {
buf = format!("method `{}` references the `Self` type \
in its arguments or return type",
name);
&buf
}

ObjectSafetyViolation::Method(name,
MethodViolationCode::Generic) => {
buf = format!("method `{}` has generic type parameters", name);
&buf
}
};
err.note(note);
err.note(&violation.error_msg());
}
err
}
Expand Down Expand Up @@ -774,7 +710,8 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
let trait_ref = data.to_poly_trait_ref();
let self_ty = trait_ref.self_ty();
if predicate.references_error() {
} else {
return;
}
// Typically, this ambiguity should only happen if
// there are unresolved type inference variables
// (otherwise it would suggest a coherence
Expand Down Expand Up @@ -816,7 +753,6 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
}
}
}
}

ty::Predicate::WellFormed(ty) => {
// Same hacky approach as above to avoid deluging user
Expand Down
20 changes: 20 additions & 0 deletions src/librustc/traits/object_safety.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,7 @@ use hir::def_id::DefId;
use traits;
use ty::{self, Ty, TyCtxt, TypeFoldable};
use ty::subst::Substs;
use std::borrow::Cow;
use syntax::ast;

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
Expand All @@ -38,6 +39,25 @@ pub enum ObjectSafetyViolation {
Method(ast::Name, MethodViolationCode),
}

impl ObjectSafetyViolation {
pub fn error_msg(&self) -> Cow<'static, str> {
match *self {
ObjectSafetyViolation::SizedSelf =>
"the trait cannot require that `Self : Sized`".into(),
ObjectSafetyViolation::SupertraitSelf =>
"the trait cannot use `Self` as a type parameter \
in the supertrait listing".into(),
ObjectSafetyViolation::Method(name, MethodViolationCode::StaticMethod) =>
format!("method `{}` has no receiver", name).into(),
ObjectSafetyViolation::Method(name, MethodViolationCode::ReferencesSelf) =>
format!("method `{}` references the `Self` type \
in its arguments or return type", name).into(),
ObjectSafetyViolation::Method(name, MethodViolationCode::Generic) =>
format!("method `{}` has generic type parameters", name).into(),
}
}
}

/// Reasons a method might not be object-safe.
#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
pub enum MethodViolationCode {
Expand Down
18 changes: 0 additions & 18 deletions src/librustc/ty/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1086,24 +1086,6 @@ impl<'tcx> InstantiatedPredicates<'tcx> {
}
}

impl<'tcx> TraitRef<'tcx> {
pub fn new(def_id: DefId, substs: &'tcx Substs<'tcx>) -> TraitRef<'tcx> {
TraitRef { def_id: def_id, substs: substs }
}

pub fn self_ty(&self) -> Ty<'tcx> {
self.substs.type_at(0)
}

pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
// Select only the "input types" from a trait-reference. For
// now this is all the types that appear in the
// trait-reference, but it should eventually exclude
// associated types.
self.substs.types()
}
}

/// When type checking, we use the `ParameterEnvironment` to track
/// details about the type/lifetime parameters that are in scope.
/// It primarily stores the bounds information.
Expand Down
18 changes: 18 additions & 0 deletions src/librustc/ty/sty.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -389,6 +389,24 @@ pub struct TraitRef<'tcx> {
pub substs: &'tcx Substs<'tcx>,
}

impl<'tcx> TraitRef<'tcx> {
pub fn new(def_id: DefId, substs: &'tcx Substs<'tcx>) -> TraitRef<'tcx> {
TraitRef { def_id: def_id, substs: substs }
}

pub fn self_ty(&self) -> Ty<'tcx> {
self.substs.type_at(0)
}

pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
// Select only the "input types" from a trait-reference. For
// now this is all the types that appear in the
// trait-reference, but it should eventually exclude
// associated types.
self.substs.types()
}
}

pub type PolyTraitRef<'tcx> = Binder<TraitRef<'tcx>>;

impl<'tcx> PolyTraitRef<'tcx> {
Expand Down