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Auto merge of #106171 - compiler-errors:consolidate-extract_callable_info, r=estebank,lcnr 

Consolidate two almost duplicated fn info extraction routines

Moves `extract_callable_info` up to trait selection, because it was being (almost) duplicated fully there for similar diagnostic purposes. This also generalizes the diagnostics we can give slightly (see UI test).
This commit is contained in:
bors 2023-01-15 12:10:36 +00:00
parent bbb36fe545 c1a7dbc0e3
commit fc11ee02ee
7 changed files with 183 additions and 185 deletions
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3
compiler/rustc_hir_typeck/src/callee.rs
View File

@ -659,8 +659,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
};
if !self.maybe_suggest_bad_array_definition(&mut err, call_expr, callee_expr) {
if let Some((maybe_def, output_ty, _)) =
self.extract_callable_info(callee_expr, callee_ty)
if let Some((maybe_def, output_ty, _)) = self.extract_callable_info(callee_ty)
&& !self.type_is_sized_modulo_regions(self.param_env, output_ty, callee_expr.span)
{
let descr = match maybe_def {

103
compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
View File

@ -11,7 +11,6 @@ use rustc_hir::{
Expr, ExprKind, GenericBound, Node, Path, QPath, Stmt, StmtKind, TyKind, WherePredicate,
};
use rustc_hir_analysis::astconv::AstConv;
use rustc_infer::infer;
use rustc_infer::traits::{self, StatementAsExpression};
use rustc_middle::lint::in_external_macro;
use rustc_middle::ty::{
@ -23,9 +22,9 @@ use rustc_span::source_map::Spanned;
use rustc_span::symbol::{sym, Ident};
use rustc_span::{Span, Symbol};
use rustc_trait_selection::infer::InferCtxtExt;
use rustc_trait_selection::traits::error_reporting::suggestions::TypeErrCtxtExt;
use rustc_trait_selection::traits::error_reporting::DefIdOrName;
use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt as _;
use rustc_trait_selection::traits::NormalizeExt;
impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
pub(crate) fn body_fn_sig(&self) -> Option<ty::FnSig<'tcx>> {
@ -94,7 +93,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
found: Ty<'tcx>,
can_satisfy: impl FnOnce(Ty<'tcx>) -> bool,
) -> bool {
let Some((def_id_or_name, output, inputs)) = self.extract_callable_info(expr, found)
let Some((def_id_or_name, output, inputs)) = self.extract_callable_info(found)
else { return false; };
if can_satisfy(output) {
let (sugg_call, mut applicability) = match inputs.len() {
@ -163,99 +162,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
/// because the callable type must also be well-formed to be called.
pub(in super::super) fn extract_callable_info(
&self,
expr: &Expr<'_>,
found: Ty<'tcx>,
ty: Ty<'tcx>,
) -> Option<(DefIdOrName, Ty<'tcx>, Vec<Ty<'tcx>>)> {
// Autoderef is useful here because sometimes we box callables, etc.
let Some((def_id_or_name, output, inputs)) = self.autoderef(expr.span, found).silence_errors().find_map(|(found, _)| {
match *found.kind() {
ty::FnPtr(fn_sig) =>
Some((DefIdOrName::Name("function pointer"), fn_sig.output(), fn_sig.inputs())),
ty::FnDef(def_id, _) => {
let fn_sig = found.fn_sig(self.tcx);
Some((DefIdOrName::DefId(def_id), fn_sig.output(), fn_sig.inputs()))
}
ty::Closure(def_id, substs) => {
let fn_sig = substs.as_closure().sig();
Some((DefIdOrName::DefId(def_id), fn_sig.output(), fn_sig.inputs().map_bound(|inputs| &inputs[1..])))
}
ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) => {
self.tcx.bound_item_bounds(def_id).subst(self.tcx, substs).iter().find_map(|pred| {
if let ty::PredicateKind::Clause(ty::Clause::Projection(proj)) = pred.kind().skip_binder()
&& Some(proj.projection_ty.def_id) == self.tcx.lang_items().fn_once_output()
// args tuple will always be substs[1]
&& let ty::Tuple(args) = proj.projection_ty.substs.type_at(1).kind()
{
Some((
DefIdOrName::DefId(def_id),
pred.kind().rebind(proj.term.ty().unwrap()),
pred.kind().rebind(args.as_slice()),
))
} else {
None
}
})
}
ty::Dynamic(data, _, ty::Dyn) => {
data.iter().find_map(|pred| {
if let ty::ExistentialPredicate::Projection(proj) = pred.skip_binder()
&& Some(proj.def_id) == self.tcx.lang_items().fn_once_output()
// for existential projection, substs are shifted over by 1
&& let ty::Tuple(args) = proj.substs.type_at(0).kind()
{
Some((
DefIdOrName::Name("trait object"),
pred.rebind(proj.term.ty().unwrap()),
pred.rebind(args.as_slice()),
))
} else {
None
}
})
}
ty::Param(param) => {
let def_id = self.tcx.generics_of(self.body_id.owner).type_param(&param, self.tcx).def_id;
self.tcx.predicates_of(self.body_id.owner).predicates.iter().find_map(|(pred, _)| {
if let ty::PredicateKind::Clause(ty::Clause::Projection(proj)) = pred.kind().skip_binder()
&& Some(proj.projection_ty.def_id) == self.tcx.lang_items().fn_once_output()
&& proj.projection_ty.self_ty() == found
// args tuple will always be substs[1]
&& let ty::Tuple(args) = proj.projection_ty.substs.type_at(1).kind()
{
Some((
DefIdOrName::DefId(def_id),
pred.kind().rebind(proj.term.ty().unwrap()),
pred.kind().rebind(args.as_slice()),
))
} else {
None
}
})
}
_ => None,
}
}) else { return None; };
let output = self.replace_bound_vars_with_fresh_vars(expr.span, infer::FnCall, output);
let inputs = inputs
.skip_binder()
.iter()
.map(|ty| {
self.replace_bound_vars_with_fresh_vars(
expr.span,
infer::FnCall,
inputs.rebind(*ty),
)
})
.collect();
// We don't want to register any extra obligations, which should be
// implied by wf, but also because that would possibly result in
// erroneous errors later on.
let infer::InferOk { value: output, obligations: _ } =
self.at(&self.misc(expr.span), self.param_env).normalize(output);
if output.is_ty_var() { None } else { Some((def_id_or_name, output, inputs)) }
self.err_ctxt().extract_callable_info(self.body_id, self.param_env, ty)
}
pub fn suggest_two_fn_call(
@ -267,9 +176,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
rhs_ty: Ty<'tcx>,
can_satisfy: impl FnOnce(Ty<'tcx>, Ty<'tcx>) -> bool,
) -> bool {
let Some((_, lhs_output_ty, lhs_inputs)) = self.extract_callable_info(lhs_expr, lhs_ty)
let Some((_, lhs_output_ty, lhs_inputs)) = self.extract_callable_info(lhs_ty)
else { return false; };
let Some((_, rhs_output_ty, rhs_inputs)) = self.extract_callable_info(rhs_expr, rhs_ty)
let Some((_, rhs_output_ty, rhs_inputs)) = self.extract_callable_info(rhs_ty)
else { return false; };
if can_satisfy(lhs_output_ty, rhs_output_ty) {

6
compiler/rustc_hir_typeck/src/method/suggest.rs
View File

@ -2700,8 +2700,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
found: Ty<'tcx>,
expected: Ty<'tcx>,
) -> bool {
let Some((_def_id_or_name, output, _inputs)) = self.extract_callable_info(expr, found)
else { return false; };
let Some((_def_id_or_name, output, _inputs)) =
self.extract_callable_info(found) else {
return false;
};
if !self.can_coerce(output, expected) {
return false;

1
compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
View File

@ -2937,6 +2937,7 @@ impl<'tcx> ty::TypeVisitor<'tcx> for HasNumericInferVisitor {
}
}
#[derive(Copy, Clone)]
pub enum DefIdOrName {
DefId(DefId),
Name(&'static str),

221
compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
View File

@ -212,6 +212,13 @@ pub trait TypeErrCtxtExt<'tcx> {
trait_pred: ty::PolyTraitPredicate<'tcx>,
) -> bool;
fn extract_callable_info(
&self,
hir_id: HirId,
param_env: ty::ParamEnv<'tcx>,
found: Ty<'tcx>,
) -> Option<(DefIdOrName, Ty<'tcx>, Vec<Ty<'tcx>>)>;
fn suggest_add_reference_to_arg(
&self,
obligation: &PredicateObligation<'tcx>,
@ -878,6 +885,12 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
err: &mut Diagnostic,
trait_pred: ty::PolyTraitPredicate<'tcx>,
) -> bool {
// It doesn't make sense to make this suggestion outside of typeck...
// (also autoderef will ICE...)
if self.typeck_results.is_none() {
return false;
}
if let ty::PredicateKind::Clause(ty::Clause::Trait(trait_pred)) = obligation.predicate.kind().skip_binder()
&& Some(trait_pred.def_id()) == self.tcx.lang_items().sized_trait()
{
@ -885,92 +898,17 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
return false;
}
// This is duplicated from `extract_callable_info` in typeck, which
// relies on autoderef, so we can't use it here.
let found = trait_pred.self_ty().skip_binder().peel_refs();
let Some((def_id_or_name, output, inputs)) = (match *found.kind()
{
ty::FnPtr(fn_sig) => {
Some((DefIdOrName::Name("function pointer"), fn_sig.output(), fn_sig.inputs()))
}
ty::FnDef(def_id, _) => {
let fn_sig = found.fn_sig(self.tcx);
Some((DefIdOrName::DefId(def_id), fn_sig.output(), fn_sig.inputs()))
}
ty::Closure(def_id, substs) => {
let fn_sig = substs.as_closure().sig();
Some((
DefIdOrName::DefId(def_id),
fn_sig.output(),
fn_sig.inputs().map_bound(|inputs| &inputs[1..]),
))
}
ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) => {
self.tcx.bound_item_bounds(def_id).subst(self.tcx, substs).iter().find_map(|pred| {
if let ty::PredicateKind::Clause(ty::Clause::Projection(proj)) = pred.kind().skip_binder()
&& Some(proj.projection_ty.def_id) == self.tcx.lang_items().fn_once_output()
// args tuple will always be substs[1]
&& let ty::Tuple(args) = proj.projection_ty.substs.type_at(1).kind()
{
Some((
DefIdOrName::DefId(def_id),
pred.kind().rebind(proj.term.ty().unwrap()),
pred.kind().rebind(args.as_slice()),
))
} else {
None
}
})
}
ty::Dynamic(data, _, ty::Dyn) => {
data.iter().find_map(|pred| {
if let ty::ExistentialPredicate::Projection(proj) = pred.skip_binder()
&& Some(proj.def_id) == self.tcx.lang_items().fn_once_output()
// for existential projection, substs are shifted over by 1
&& let ty::Tuple(args) = proj.substs.type_at(0).kind()
{
Some((
DefIdOrName::Name("trait object"),
pred.rebind(proj.term.ty().unwrap()),
pred.rebind(args.as_slice()),
))
} else {
None
}
})
}
ty::Param(_) => {
obligation.param_env.caller_bounds().iter().find_map(|pred| {
if let ty::PredicateKind::Clause(ty::Clause::Projection(proj)) = pred.kind().skip_binder()
&& Some(proj.projection_ty.def_id) == self.tcx.lang_items().fn_once_output()
&& proj.projection_ty.self_ty() == found
// args tuple will always be substs[1]
&& let ty::Tuple(args) = proj.projection_ty.substs.type_at(1).kind()
{
Some((
DefIdOrName::Name("type parameter"),
pred.kind().rebind(proj.term.ty().unwrap()),
pred.kind().rebind(args.as_slice()),
))
} else {
None
}
})
}
_ => None,
}) else { return false; };
let output = self.replace_bound_vars_with_fresh_vars(
obligation.cause.span,
let self_ty = self.replace_bound_vars_with_fresh_vars(
DUMMY_SP,
LateBoundRegionConversionTime::FnCall,
output,
trait_pred.self_ty(),
);
let inputs = inputs.skip_binder().iter().map(|ty| {
self.replace_bound_vars_with_fresh_vars(
obligation.cause.span,
LateBoundRegionConversionTime::FnCall,
inputs.rebind(*ty),
)
});
let Some((def_id_or_name, output, inputs)) = self.extract_callable_info(
obligation.cause.body_id,
obligation.param_env,
self_ty,
) else { return false; };
// Remapping bound vars here
let trait_pred_and_self = trait_pred.map_bound(|trait_pred| (trait_pred, output));
@ -998,6 +936,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
};
let args = inputs
.into_iter()
.map(|ty| {
if ty.is_suggestable(self.tcx, false) {
format!("/* {ty} */")
@ -1161,6 +1100,120 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
false
}
/// Extracts information about a callable type for diagnostics. This is a
/// heuristic -- it doesn't necessarily mean that a type is always callable,
/// because the callable type must also be well-formed to be called.
fn extract_callable_info(
&self,
hir_id: HirId,
param_env: ty::ParamEnv<'tcx>,
found: Ty<'tcx>,
) -> Option<(DefIdOrName, Ty<'tcx>, Vec<Ty<'tcx>>)> {
// Autoderef is useful here because sometimes we box callables, etc.
let Some((def_id_or_name, output, inputs)) = (self.autoderef_steps)(found).into_iter().find_map(|(found, _)| {
match *found.kind() {
ty::FnPtr(fn_sig) =>
Some((DefIdOrName::Name("function pointer"), fn_sig.output(), fn_sig.inputs())),
ty::FnDef(def_id, _) => {
let fn_sig = found.fn_sig(self.tcx);
Some((DefIdOrName::DefId(def_id), fn_sig.output(), fn_sig.inputs()))
}
ty::Closure(def_id, substs) => {
let fn_sig = substs.as_closure().sig();
Some((DefIdOrName::DefId(def_id), fn_sig.output(), fn_sig.inputs().map_bound(|inputs| &inputs[1..])))
}
ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) => {
self.tcx.bound_item_bounds(def_id).subst(self.tcx, substs).iter().find_map(|pred| {
if let ty::PredicateKind::Clause(ty::Clause::Projection(proj)) = pred.kind().skip_binder()
&& Some(proj.projection_ty.def_id) == self.tcx.lang_items().fn_once_output()
// args tuple will always be substs[1]
&& let ty::Tuple(args) = proj.projection_ty.substs.type_at(1).kind()
{
Some((
DefIdOrName::DefId(def_id),
pred.kind().rebind(proj.term.ty().unwrap()),
pred.kind().rebind(args.as_slice()),
))
} else {
None
}
})
}
ty::Dynamic(data, _, ty::Dyn) => {
data.iter().find_map(|pred| {
if let ty::ExistentialPredicate::Projection(proj) = pred.skip_binder()
&& Some(proj.def_id) == self.tcx.lang_items().fn_once_output()
// for existential projection, substs are shifted over by 1
&& let ty::Tuple(args) = proj.substs.type_at(0).kind()
{
Some((
DefIdOrName::Name("trait object"),
pred.rebind(proj.term.ty().unwrap()),
pred.rebind(args.as_slice()),
))
} else {
None
}
})
}
ty::Param(param) => {
let generics = self.tcx.generics_of(hir_id.owner.to_def_id());
let name = if generics.count() > param.index as usize
&& let def = generics.param_at(param.index as usize, self.tcx)
&& matches!(def.kind, ty::GenericParamDefKind::Type { .. })
&& def.name == param.name
{
DefIdOrName::DefId(def.def_id)
} else {
DefIdOrName::Name("type parameter")
};
param_env.caller_bounds().iter().find_map(|pred| {
if let ty::PredicateKind::Clause(ty::Clause::Projection(proj)) = pred.kind().skip_binder()
&& Some(proj.projection_ty.def_id) == self.tcx.lang_items().fn_once_output()
&& proj.projection_ty.self_ty() == found
// args tuple will always be substs[1]
&& let ty::Tuple(args) = proj.projection_ty.substs.type_at(1).kind()
{
Some((
name,
pred.kind().rebind(proj.term.ty().unwrap()),
pred.kind().rebind(args.as_slice()),
))
} else {
None
}
})
}
_ => None,
}
}) else { return None; };
let output = self.replace_bound_vars_with_fresh_vars(
DUMMY_SP,
LateBoundRegionConversionTime::FnCall,
output,
);
let inputs = inputs
.skip_binder()
.iter()
.map(|ty| {
self.replace_bound_vars_with_fresh_vars(
DUMMY_SP,
LateBoundRegionConversionTime::FnCall,
inputs.rebind(*ty),
)
})
.collect();
// We don't want to register any extra obligations, which should be
// implied by wf, but also because that would possibly result in
// erroneous errors later on.
let InferOk { value: output, obligations: _ } =
self.at(&ObligationCause::dummy(), param_env).normalize(output);
if output.is_ty_var() { None } else { Some((def_id_or_name, output, inputs)) }
}
fn suggest_add_reference_to_arg(
&self,
obligation: &PredicateObligation<'tcx>,

13
tests/ui/suggestions/call-on-unimplemented-with-autoderef.rs Normal file
View File

@ -0,0 +1,13 @@
trait Foo {}
impl Foo for i32 {}
fn needs_foo(_: impl Foo) {}
fn test(x: &Box<dyn Fn() -> i32>) {
needs_foo(x);
//~^ ERROR the trait bound
//~| HELP use parentheses to call this trait object
}
fn main() {}

21
tests/ui/suggestions/call-on-unimplemented-with-autoderef.stderr Normal file
View File

@ -0,0 +1,21 @@
error[E0277]: the trait bound `&Box<dyn Fn() -> i32>: Foo` is not satisfied
--> $DIR/call-on-unimplemented-with-autoderef.rs:8:15
|
LL | needs_foo(x);
| --------- ^ the trait `Foo` is not implemented for `&Box<dyn Fn() -> i32>`
| |
| required by a bound introduced by this call
|
note: required by a bound in `needs_foo`
--> $DIR/call-on-unimplemented-with-autoderef.rs:5:22
|
LL | fn needs_foo(_: impl Foo) {}
| ^^^ required by this bound in `needs_foo`
help: use parentheses to call this trait object
|
LL | needs_foo(x());
| ++
error: aborting due to previous error
For more information about this error, try `rustc --explain E0277`.