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Rollup merge of #105523 - estebank:suggest-collect-vec, r=compiler-errors

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Suggest `collect`ing into `Vec<_>`

Fix #105510.
This commit is contained in:
Matthias Krüger 2022-12-14 10:31:07 +01:00 • committed by GitHub
commit e5fde968db
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GPG key ID: 4AEE18F83AFDEB23
31 changed files with 168 additions and 151 deletions
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104
compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs
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@ -20,7 +20,7 @@ use rustc_middle::ty::print::{FmtPrinter, PrettyPrinter, Print, Printer};
use rustc_middle::ty::{self, DefIdTree, InferConst};
use rustc_middle::ty::{GenericArg, GenericArgKind, SubstsRef};
use rustc_middle::ty::{IsSuggestable, Ty, TyCtxt, TypeckResults};
use rustc_span::symbol::{kw, Ident};
use rustc_span::symbol::{kw, sym, Ident};
use rustc_span::{BytePos, Span};
use std::borrow::Cow;
use std::iter;
@ -79,7 +79,7 @@ impl InferenceDiagnosticsData {
fn where_x_is_kind(&self, in_type: Ty<'_>) -> &'static str {
if in_type.is_ty_infer() {
"empty"
""
} else if self.name == "_" {
// FIXME: Consider specializing this message if there is a single `_`
// in the type.
@ -183,13 +183,24 @@ fn fmt_printer<'a, 'tcx>(infcx: &'a InferCtxt<'tcx>, ns: Namespace) -> FmtPrinte
printer
}
fn ty_to_string<'tcx>(infcx: &InferCtxt<'tcx>, ty: Ty<'tcx>) -> String {
fn ty_to_string<'tcx>(
infcx: &InferCtxt<'tcx>,
ty: Ty<'tcx>,
called_method_def_id: Option<DefId>,
) -> String {
let printer = fmt_printer(infcx, Namespace::TypeNS);
let ty = infcx.resolve_vars_if_possible(ty);
match ty.kind() {
match (ty.kind(), called_method_def_id) {
// We don't want the regular output for `fn`s because it includes its path in
// invalid pseudo-syntax, we want the `fn`-pointer output instead.
ty::FnDef(..) => ty.fn_sig(infcx.tcx).print(printer).unwrap().into_buffer(),
(ty::FnDef(..), _) => ty.fn_sig(infcx.tcx).print(printer).unwrap().into_buffer(),
(_, Some(def_id))
if ty.is_ty_infer()
&& infcx.tcx.get_diagnostic_item(sym::iterator_collect_fn) == Some(def_id) =>
{
"Vec<_>".to_string()
}
_ if ty.is_ty_infer() => "/* Type */".to_string(),
// FIXME: The same thing for closures, but this only works when the closure
// does not capture anything.
//
@ -213,7 +224,7 @@ fn closure_as_fn_str<'tcx>(infcx: &InferCtxt<'tcx>, ty: Ty<'tcx>) -> String {
.map(|args| {
args.tuple_fields()
.iter()
.map(|arg| ty_to_string(infcx, arg))
.map(|arg| ty_to_string(infcx, arg, None))
.collect::<Vec<_>>()
.join(", ")
})
@ -221,7 +232,7 @@ fn closure_as_fn_str<'tcx>(infcx: &InferCtxt<'tcx>, ty: Ty<'tcx>) -> String {
let ret = if fn_sig.output().skip_binder().is_unit() {
String::new()
} else {
format!(" -> {}", ty_to_string(infcx, fn_sig.output().skip_binder()))
format!(" -> {}", ty_to_string(infcx, fn_sig.output().skip_binder(), None))
};
format!("fn({}){}", args, ret)
}
@ -368,6 +379,7 @@ impl<'tcx> InferCtxt<'tcx> {
}
impl<'tcx> TypeErrCtxt<'_, 'tcx> {
#[instrument(level = "debug", skip(self, error_code))]
pub fn emit_inference_failure_err(
&self,
body_id: Option<hir::BodyId>,
@ -406,7 +418,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
let mut infer_subdiags = Vec::new();
let mut multi_suggestions = Vec::new();
match kind {
InferSourceKind::LetBinding { insert_span, pattern_name, ty } => {
InferSourceKind::LetBinding { insert_span, pattern_name, ty, def_id } => {
infer_subdiags.push(SourceKindSubdiag::LetLike {
span: insert_span,
name: pattern_name.map(|name| name.to_string()).unwrap_or_else(String::new),
@ -415,7 +427,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
prefix: arg_data.kind.try_get_prefix().unwrap_or_default(),
arg_name: arg_data.name,
kind: if pattern_name.is_some() { "with_pattern" } else { "other" },
type_name: ty_to_string(self, ty),
type_name: ty_to_string(self, ty, def_id),
});
}
InferSourceKind::ClosureArg { insert_span, ty } => {
@ -427,7 +439,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
prefix: arg_data.kind.try_get_prefix().unwrap_or_default(),
arg_name: arg_data.name,
kind: "closure",
type_name: ty_to_string(self, ty),
type_name: ty_to_string(self, ty, None),
});
}
InferSourceKind::GenericArg {
@ -456,33 +468,39 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
parent_name,
});
let args = fmt_printer(self, Namespace::TypeNS)
.comma_sep(generic_args.iter().copied().map(|arg| {
if arg.is_suggestable(self.tcx, true) {
return arg;
}
let args = if self.infcx.tcx.get_diagnostic_item(sym::iterator_collect_fn)
== Some(generics_def_id)
{
"Vec<_>".to_string()
} else {
fmt_printer(self, Namespace::TypeNS)
.comma_sep(generic_args.iter().copied().map(|arg| {
if arg.is_suggestable(self.tcx, true) {
return arg;
}
match arg.unpack() {
GenericArgKind::Lifetime(_) => bug!("unexpected lifetime"),
GenericArgKind::Type(_) => self
.next_ty_var(TypeVariableOrigin {
span: rustc_span::DUMMY_SP,
kind: TypeVariableOriginKind::MiscVariable,
})
.into(),
GenericArgKind::Const(arg) => self
.next_const_var(
arg.ty(),
ConstVariableOrigin {
match arg.unpack() {
GenericArgKind::Lifetime(_) => bug!("unexpected lifetime"),
GenericArgKind::Type(_) => self
.next_ty_var(TypeVariableOrigin {
span: rustc_span::DUMMY_SP,
kind: ConstVariableOriginKind::MiscVariable,
},
)
.into(),
}
}))
.unwrap()
.into_buffer();
kind: TypeVariableOriginKind::MiscVariable,
})
.into(),
GenericArgKind::Const(arg) => self
.next_const_var(
arg.ty(),
ConstVariableOrigin {
span: rustc_span::DUMMY_SP,
kind: ConstVariableOriginKind::MiscVariable,
},
)
.into(),
}
}))
.unwrap()
.into_buffer()
};
if !have_turbofish {
infer_subdiags.push(SourceKindSubdiag::GenericSuggestion {
@ -520,7 +538,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
));
}
InferSourceKind::ClosureReturn { ty, data, should_wrap_expr } => {
let ty_info = ty_to_string(self, ty);
let ty_info = ty_to_string(self, ty, None);
multi_suggestions.push(SourceKindMultiSuggestion::new_closure_return(
ty_info,
data,
@ -608,6 +626,7 @@ enum InferSourceKind<'tcx> {
insert_span: Span,
pattern_name: Option<Ident>,
ty: Ty<'tcx>,
def_id: Option<DefId>,
},
ClosureArg {
insert_span: Span,
@ -662,7 +681,7 @@ impl<'tcx> InferSourceKind<'tcx> {
if ty.is_closure() {
("closure", closure_as_fn_str(infcx, ty))
} else if !ty.is_ty_infer() {
("normal", ty_to_string(infcx, ty))
("normal", ty_to_string(infcx, ty, None))
} else {
("other", String::new())
}
@ -788,10 +807,18 @@ impl<'a, 'tcx> FindInferSourceVisitor<'a, 'tcx> {
/// Uses `fn source_cost` to determine whether this inference source is preferable to
/// previous sources. We generally prefer earlier sources.
#[instrument(level = "debug", skip(self))]
fn update_infer_source(&mut self, new_source: InferSource<'tcx>) {
fn update_infer_source(&mut self, mut new_source: InferSource<'tcx>) {
let cost = self.source_cost(&new_source) + self.attempt;
debug!(?cost);
self.attempt += 1;
if let Some(InferSource { kind: InferSourceKind::GenericArg { def_id: did, ..}, .. }) = self.infer_source
&& let InferSourceKind::LetBinding { ref ty, ref mut def_id, ..} = new_source.kind
&& ty.is_ty_infer()
{
// Customize the output so we talk about `let x: Vec<_> = iter.collect();` instead of
// `let x: _ = iter.collect();`, as this is a very common case.
*def_id = Some(did);
}
if cost < self.infer_source_cost {
self.infer_source_cost = cost;
self.infer_source = Some(new_source);
@ -1092,6 +1119,7 @@ impl<'a, 'tcx> Visitor<'tcx> for FindInferSourceVisitor<'a, 'tcx> {
insert_span: local.pat.span.shrink_to_hi(),
pattern_name: local.pat.simple_ident(),
ty,
def_id: None,
},
})
}