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Rollup merge of #99539 - compiler-errors:bidirectional-block-suggestions, r=fee1-dead

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Improve suggestions for returning binding

Fixes #99525

Also reworks the cause codes for match and if a bit, I think cleaning them up in a positive way.
We no longer need to call `could_remove_semicolon` in successful code, which might save a few cycles?
This commit is contained in:
Dylan DPC 2022-07-22 11:53:42 +05:30 • committed by GitHub
commit 92bebac0b9
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13 changed files with 625 additions and 467 deletions
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539
compiler/rustc_infer/src/infer/error_reporting/mod.rs
View file

@ -316,37 +316,6 @@ pub fn unexpected_hidden_region_diagnostic<'tcx>(
err
}
/// Structurally compares two types, modulo any inference variables.
///
/// Returns `true` if two types are equal, or if one type is an inference variable compatible
/// with the other type. A TyVar inference type is compatible with any type, and an IntVar or
/// FloatVar inference type are compatible with themselves or their concrete types (Int and
/// Float types, respectively). When comparing two ADTs, these rules apply recursively.
pub fn same_type_modulo_infer<'tcx>(a: Ty<'tcx>, b: Ty<'tcx>) -> bool {
match (&a.kind(), &b.kind()) {
(&ty::Adt(did_a, substs_a), &ty::Adt(did_b, substs_b)) => {
if did_a != did_b {
return false;
}
substs_a.types().zip(substs_b.types()).all(|(a, b)| same_type_modulo_infer(a, b))
}
(&ty::Int(_), &ty::Infer(ty::InferTy::IntVar(_)))
| (&ty::Infer(ty::InferTy::IntVar(_)), &ty::Int(_) | &ty::Infer(ty::InferTy::IntVar(_)))
| (&ty::Float(_), &ty::Infer(ty::InferTy::FloatVar(_)))
| (
&ty::Infer(ty::InferTy::FloatVar(_)),
&ty::Float(_) | &ty::Infer(ty::InferTy::FloatVar(_)),
)
| (&ty::Infer(ty::InferTy::TyVar(_)), _)
| (_, &ty::Infer(ty::InferTy::TyVar(_))) => true,
(&ty::Ref(_, ty_a, mut_a), &ty::Ref(_, ty_b, mut_b)) => {
mut_a == mut_b && same_type_modulo_infer(*ty_a, *ty_b)
}
_ => a == b,
}
}
impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
pub fn report_region_errors(
&self,
@ -645,13 +614,16 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
err.span_label(span, "expected due to this");
}
ObligationCauseCode::MatchExpressionArm(box MatchExpressionArmCause {
semi_span,
arm_block_id,
arm_span,
arm_ty,
prior_arm_block_id,
prior_arm_span,
prior_arm_ty,
source,
ref prior_arms,
last_ty,
scrut_hir_id,
opt_suggest_box_span,
arm_span,
scrut_span,
..
}) => match source {
@ -682,10 +654,10 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
}
}
_ => {
// `last_ty` can be `!`, `expected` will have better info when present.
// `prior_arm_ty` can be `!`, `expected` will have better info when present.
let t = self.resolve_vars_if_possible(match exp_found {
Some(ty::error::ExpectedFound { expected, .. }) => expected,
_ => last_ty,
_ => prior_arm_ty,
});
let source_map = self.tcx.sess.source_map();
let mut any_multiline_arm = source_map.is_multiline(arm_span);
@ -710,37 +682,15 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
};
let msg = "`match` arms have incompatible types";
err.span_label(outer_error_span, msg);
if let Some((sp, boxed)) = semi_span {
if let (StatementAsExpression::NeedsBoxing, [.., prior_arm]) =
(boxed, &prior_arms[..])
{
err.multipart_suggestion(
"consider removing this semicolon and boxing the expressions",
vec![
(prior_arm.shrink_to_lo(), "Box::new(".to_string()),
(prior_arm.shrink_to_hi(), ")".to_string()),
(arm_span.shrink_to_lo(), "Box::new(".to_string()),
(arm_span.shrink_to_hi(), ")".to_string()),
(sp, String::new()),
],
Applicability::HasPlaceholders,
);
} else if matches!(boxed, StatementAsExpression::NeedsBoxing) {
err.span_suggestion_short(
sp,
"consider removing this semicolon and boxing the expressions",
"",
Applicability::MachineApplicable,
);
} else {
err.span_suggestion_short(
sp,
"consider removing this semicolon",
"",
Applicability::MachineApplicable,
);
}
}
self.suggest_remove_semi_or_return_binding(
err,
prior_arm_block_id,
prior_arm_ty,
prior_arm_span,
arm_block_id,
arm_ty,
arm_span,
);
if let Some(ret_sp) = opt_suggest_box_span {
// Get return type span and point to it.
self.suggest_boxing_for_return_impl_trait(
@ -752,43 +702,33 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
}
},
ObligationCauseCode::IfExpression(box IfExpressionCause {
then,
else_sp,
outer,
semicolon,
then_id,
else_id,
then_ty,
else_ty,
outer_span,
opt_suggest_box_span,
}) => {
err.span_label(then, "expected because of this");
if let Some(sp) = outer {
let then_span = self.find_block_span_from_hir_id(then_id);
let else_span = self.find_block_span_from_hir_id(then_id);
err.span_label(then_span, "expected because of this");
if let Some(sp) = outer_span {
err.span_label(sp, "`if` and `else` have incompatible types");
}
if let Some((sp, boxed)) = semicolon {
if matches!(boxed, StatementAsExpression::NeedsBoxing) {
err.multipart_suggestion(
"consider removing this semicolon and boxing the expression",
vec![
(then.shrink_to_lo(), "Box::new(".to_string()),
(then.shrink_to_hi(), ")".to_string()),
(else_sp.shrink_to_lo(), "Box::new(".to_string()),
(else_sp.shrink_to_hi(), ")".to_string()),
(sp, String::new()),
],
Applicability::MachineApplicable,
);
} else {
err.span_suggestion_short(
sp,
"consider removing this semicolon",
"",
Applicability::MachineApplicable,
);
}
}
self.suggest_remove_semi_or_return_binding(
err,
Some(then_id),
then_ty,
then_span,
Some(else_id),
else_ty,
else_span,
);
if let Some(ret_sp) = opt_suggest_box_span {
self.suggest_boxing_for_return_impl_trait(
err,
ret_sp,
[then, else_sp].into_iter(),
[then_span, else_span].into_iter(),
);
}
}
@ -808,6 +748,56 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
}
}
fn suggest_remove_semi_or_return_binding(
&self,
err: &mut Diagnostic,
first_id: Option<hir::HirId>,
first_ty: Ty<'tcx>,
first_span: Span,
second_id: Option<hir::HirId>,
second_ty: Ty<'tcx>,
second_span: Span,
) {
let remove_semicolon =
[(first_id, second_ty), (second_id, first_ty)].into_iter().find_map(|(id, ty)| {
let hir::Node::Block(blk) = self.tcx.hir().get(id?) else { return None };
self.could_remove_semicolon(blk, ty)
});
match remove_semicolon {
Some((sp, StatementAsExpression::NeedsBoxing)) => {
err.multipart_suggestion(
"consider removing this semicolon and boxing the expressions",
vec![
(first_span.shrink_to_lo(), "Box::new(".to_string()),
(first_span.shrink_to_hi(), ")".to_string()),
(second_span.shrink_to_lo(), "Box::new(".to_string()),
(second_span.shrink_to_hi(), ")".to_string()),
(sp, String::new()),
],
Applicability::MachineApplicable,
);
}
Some((sp, StatementAsExpression::CorrectType)) => {
err.span_suggestion_short(
sp,
"consider removing this semicolon",
"",
Applicability::MachineApplicable,
);
}
None => {
for (id, ty) in [(first_id, second_ty), (second_id, first_ty)] {
if let Some(id) = id
&& let hir::Node::Block(blk) = self.tcx.hir().get(id)
&& self.consider_returning_binding(blk, ty, err)
{
break;
}
}
}
}
}
fn suggest_boxing_for_return_impl_trait(
&self,
err: &mut Diagnostic,
@ -1723,15 +1713,14 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
};
debug!("exp_found {:?} terr {:?} cause.code {:?}", exp_found, terr, cause.code());
if let Some(exp_found) = exp_found {
let should_suggest_fixes = if let ObligationCauseCode::Pattern { root_ty, .. } =
cause.code()
{
// Skip if the root_ty of the pattern is not the same as the expected_ty.
// If these types aren't equal then we've probably peeled off a layer of arrays.
same_type_modulo_infer(self.resolve_vars_if_possible(*root_ty), exp_found.expected)
} else {
true
};
let should_suggest_fixes =
if let ObligationCauseCode::Pattern { root_ty, .. } = cause.code() {
// Skip if the root_ty of the pattern is not the same as the expected_ty.
// If these types aren't equal then we've probably peeled off a layer of arrays.
self.same_type_modulo_infer(*root_ty, exp_found.expected)
} else {
true
};
if should_suggest_fixes {
self.suggest_tuple_pattern(cause, &exp_found, diag);
@ -1786,7 +1775,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
.filter_map(|variant| {
let sole_field = &variant.fields[0];
let sole_field_ty = sole_field.ty(self.tcx, substs);
if same_type_modulo_infer(sole_field_ty, exp_found.found) {
if self.same_type_modulo_infer(sole_field_ty, exp_found.found) {
let variant_path =
with_no_trimmed_paths!(self.tcx.def_path_str(variant.def_id));
// FIXME #56861: DRYer prelude filtering
@ -1902,12 +1891,15 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
self.get_impl_future_output_ty(exp_found.expected).map(Binder::skip_binder),
self.get_impl_future_output_ty(exp_found.found).map(Binder::skip_binder),
) {
(Some(exp), Some(found)) if same_type_modulo_infer(exp, found) => match cause.code() {
ObligationCauseCode::IfExpression(box IfExpressionCause { then, .. }) => {
(Some(exp), Some(found)) if self.same_type_modulo_infer(exp, found) => match cause
.code()
{
ObligationCauseCode::IfExpression(box IfExpressionCause { then_id, .. }) => {
let then_span = self.find_block_span_from_hir_id(*then_id);
diag.multipart_suggestion(
"consider `await`ing on both `Future`s",
vec![
(then.shrink_to_hi(), ".await".to_string()),
(then_span.shrink_to_hi(), ".await".to_string()),
(exp_span.shrink_to_hi(), ".await".to_string()),
],
Applicability::MaybeIncorrect,
@ -1934,7 +1926,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
diag.help("consider `await`ing on both `Future`s");
}
},
(_, Some(ty)) if same_type_modulo_infer(exp_found.expected, ty) => {
(_, Some(ty)) if self.same_type_modulo_infer(exp_found.expected, ty) => {
diag.span_suggestion_verbose(
exp_span.shrink_to_hi(),
"consider `await`ing on the `Future`",
@ -1942,11 +1934,20 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
Applicability::MaybeIncorrect,
);
}
(Some(ty), _) if same_type_modulo_infer(ty, exp_found.found) => match cause.code() {
ObligationCauseCode::Pattern { span: Some(span), .. }
| ObligationCauseCode::IfExpression(box IfExpressionCause { then: span, .. }) => {
(Some(ty), _) if self.same_type_modulo_infer(ty, exp_found.found) => match cause.code()
{
ObligationCauseCode::Pattern { span: Some(then_span), .. } => {
diag.span_suggestion_verbose(
span.shrink_to_hi(),
then_span.shrink_to_hi(),
"consider `await`ing on the `Future`",
".await",
Applicability::MaybeIncorrect,
);
}
ObligationCauseCode::IfExpression(box IfExpressionCause { then_id, .. }) => {
let then_span = self.find_block_span_from_hir_id(*then_id);
diag.span_suggestion_verbose(
then_span.shrink_to_hi(),
"consider `await`ing on the `Future`",
".await",
Applicability::MaybeIncorrect,
@ -1992,7 +1993,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
.iter()
.filter(|field| field.vis.is_accessible_from(field.did, self.tcx))
.map(|field| (field.name, field.ty(self.tcx, expected_substs)))
.find(|(_, ty)| same_type_modulo_infer(*ty, exp_found.found))
.find(|(_, ty)| self.same_type_modulo_infer(*ty, exp_found.found))
{
if let ObligationCauseCode::Pattern { span: Some(span), .. } = *cause.code() {
if let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(span) {
@ -2057,7 +2058,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
| (_, ty::Infer(_))
| (ty::Param(_), _)
| (ty::Infer(_), _) => {}
_ if same_type_modulo_infer(exp_ty, found_ty) => {}
_ if self.same_type_modulo_infer(exp_ty, found_ty) => {}
_ => show_suggestion = false,
};
}
@ -2179,7 +2180,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
) {
let [expected_tup_elem] = expected_fields[..] else { return };
if !same_type_modulo_infer(expected_tup_elem, found) {
if !self.same_type_modulo_infer(expected_tup_elem, found) {
return;
}
@ -2647,6 +2648,76 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
span.is_desugaring(DesugaringKind::QuestionMark)
&& self.tcx.is_diagnostic_item(sym::From, trait_def_id)
}
/// Structurally compares two types, modulo any inference variables.
///
/// Returns `true` if two types are equal, or if one type is an inference variable compatible
/// with the other type. A TyVar inference type is compatible with any type, and an IntVar or
/// FloatVar inference type are compatible with themselves or their concrete types (Int and
/// Float types, respectively). When comparing two ADTs, these rules apply recursively.
pub fn same_type_modulo_infer(&self, a: Ty<'tcx>, b: Ty<'tcx>) -> bool {
let (a, b) = self.resolve_vars_if_possible((a, b));
match (a.kind(), b.kind()) {
(&ty::Adt(def_a, substs_a), &ty::Adt(def_b, substs_b)) => {
if def_a != def_b {
return false;
}
substs_a
.types()
.zip(substs_b.types())
.all(|(a, b)| self.same_type_modulo_infer(a, b))
}
(&ty::FnDef(did_a, substs_a), &ty::FnDef(did_b, substs_b)) => {
if did_a != did_b {
return false;
}
substs_a
.types()
.zip(substs_b.types())
.all(|(a, b)| self.same_type_modulo_infer(a, b))
}
(&ty::Int(_) | &ty::Uint(_), &ty::Infer(ty::InferTy::IntVar(_)))
| (
&ty::Infer(ty::InferTy::IntVar(_)),
&ty::Int(_) | &ty::Uint(_) | &ty::Infer(ty::InferTy::IntVar(_)),
)
| (&ty::Float(_), &ty::Infer(ty::InferTy::FloatVar(_)))
| (
&ty::Infer(ty::InferTy::FloatVar(_)),
&ty::Float(_) | &ty::Infer(ty::InferTy::FloatVar(_)),
)
| (&ty::Infer(ty::InferTy::TyVar(_)), _)
| (_, &ty::Infer(ty::InferTy::TyVar(_))) => true,
(&ty::Ref(_, ty_a, mut_a), &ty::Ref(_, ty_b, mut_b)) => {
mut_a == mut_b && self.same_type_modulo_infer(ty_a, ty_b)
}
(&ty::RawPtr(a), &ty::RawPtr(b)) => {
a.mutbl == b.mutbl && self.same_type_modulo_infer(a.ty, b.ty)
}
(&ty::Slice(a), &ty::Slice(b)) => self.same_type_modulo_infer(a, b),
(&ty::Array(a_ty, a_ct), &ty::Array(b_ty, b_ct)) => {
self.same_type_modulo_infer(a_ty, b_ty) && a_ct == b_ct
}
(&ty::Tuple(a), &ty::Tuple(b)) => {
if a.len() != b.len() {
return false;
}
std::iter::zip(a.iter(), b.iter()).all(|(a, b)| self.same_type_modulo_infer(a, b))
}
(&ty::FnPtr(a), &ty::FnPtr(b)) => {
let a = a.skip_binder().inputs_and_output;
let b = b.skip_binder().inputs_and_output;
if a.len() != b.len() {
return false;
}
std::iter::zip(a.iter(), b.iter()).all(|(a, b)| self.same_type_modulo_infer(a, b))
}
// FIXME(compiler-errors): This needs to be generalized more
_ => a == b,
}
}
}
impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
@ -2798,3 +2869,237 @@ impl TyCategory {
}
}
}
impl<'tcx> InferCtxt<'_, 'tcx> {
/// Given a [`hir::Block`], get the span of its last expression or
/// statement, peeling off any inner blocks.
pub fn find_block_span(&self, block: &'tcx hir::Block<'tcx>) -> Span {
let block = block.innermost_block();
if let Some(expr) = &block.expr {
expr.span
} else if let Some(stmt) = block.stmts.last() {
// possibly incorrect trailing `;` in the else arm
stmt.span
} else {
// empty block; point at its entirety
block.span
}
}
/// Given a [`hir::HirId`] for a block, get the span of its last expression
/// or statement, peeling off any inner blocks.
pub fn find_block_span_from_hir_id(&self, hir_id: hir::HirId) -> Span {
match self.tcx.hir().get(hir_id) {
hir::Node::Block(blk) => self.find_block_span(blk),
// The parser was in a weird state if either of these happen, but
// it's better not to panic.
hir::Node::Expr(e) => e.span,
_ => rustc_span::DUMMY_SP,
}
}
/// Be helpful when the user wrote `{... expr; }` and taking the `;` off
/// is enough to fix the error.
pub fn could_remove_semicolon(
&self,
blk: &'tcx hir::Block<'tcx>,
expected_ty: Ty<'tcx>,
) -> Option<(Span, StatementAsExpression)> {
let blk = blk.innermost_block();
// Do not suggest if we have a tail expr.
if blk.expr.is_some() {
return None;
}
let last_stmt = blk.stmts.last()?;
let hir::StmtKind::Semi(ref last_expr) = last_stmt.kind else {
return None;
};
let last_expr_ty = self.in_progress_typeck_results?.borrow().expr_ty_opt(*last_expr)?;
let needs_box = match (last_expr_ty.kind(), expected_ty.kind()) {
_ if last_expr_ty.references_error() => return None,
_ if self.same_type_modulo_infer(last_expr_ty, expected_ty) => {
StatementAsExpression::CorrectType
}
(ty::Opaque(last_def_id, _), ty::Opaque(exp_def_id, _))
if last_def_id == exp_def_id =>
{
StatementAsExpression::CorrectType
}
(ty::Opaque(last_def_id, last_bounds), ty::Opaque(exp_def_id, exp_bounds)) => {
debug!(
"both opaque, likely future {:?} {:?} {:?} {:?}",
last_def_id, last_bounds, exp_def_id, exp_bounds
);
let last_local_id = last_def_id.as_local()?;
let exp_local_id = exp_def_id.as_local()?;
match (
&self.tcx.hir().expect_item(last_local_id).kind,
&self.tcx.hir().expect_item(exp_local_id).kind,
) {
(
hir::ItemKind::OpaqueTy(hir::OpaqueTy { bounds: last_bounds, .. }),
hir::ItemKind::OpaqueTy(hir::OpaqueTy { bounds: exp_bounds, .. }),
) if iter::zip(*last_bounds, *exp_bounds).all(|(left, right)| {
match (left, right) {
(
hir::GenericBound::Trait(tl, ml),
hir::GenericBound::Trait(tr, mr),
) if tl.trait_ref.trait_def_id() == tr.trait_ref.trait_def_id()
&& ml == mr =>
{
true
}
(
hir::GenericBound::LangItemTrait(langl, _, _, argsl),
hir::GenericBound::LangItemTrait(langr, _, _, argsr),
) if langl == langr => {
// FIXME: consider the bounds!
debug!("{:?} {:?}", argsl, argsr);
true
}
_ => false,
}
}) =>
{
StatementAsExpression::NeedsBoxing
}
_ => StatementAsExpression::CorrectType,
}
}
_ => return None,
};
let span = if last_stmt.span.from_expansion() {
let mac_call = rustc_span::source_map::original_sp(last_stmt.span, blk.span);
self.tcx.sess.source_map().mac_call_stmt_semi_span(mac_call)?
} else {
last_stmt.span.with_lo(last_stmt.span.hi() - BytePos(1))
};
Some((span, needs_box))
}
/// Suggest returning a local binding with a compatible type if the block
/// has no return expression.
pub fn consider_returning_binding(
&self,
blk: &'tcx hir::Block<'tcx>,
expected_ty: Ty<'tcx>,
err: &mut Diagnostic,
) -> bool {
let blk = blk.innermost_block();
// Do not suggest if we have a tail expr.
if blk.expr.is_some() {
return false;
}
let mut shadowed = FxHashSet::default();
let mut candidate_idents = vec![];
let mut find_compatible_candidates = |pat: &hir::Pat<'_>| {
if let hir::PatKind::Binding(_, hir_id, ident, _) = &pat.kind
&& let Some(pat_ty) = self
.in_progress_typeck_results
.and_then(|typeck_results| typeck_results.borrow().node_type_opt(*hir_id))
{
let pat_ty = self.resolve_vars_if_possible(pat_ty);
if self.same_type_modulo_infer(pat_ty, expected_ty)
&& !(pat_ty, expected_ty).references_error()
&& shadowed.insert(ident.name)
{
candidate_idents.push((*ident, pat_ty));
}
}
true
};
let hir = self.tcx.hir();
for stmt in blk.stmts.iter().rev() {
let hir::StmtKind::Local(local) = &stmt.kind else { continue; };
local.pat.walk(&mut find_compatible_candidates);
}
match hir.find(hir.get_parent_node(blk.hir_id)) {
Some(hir::Node::Expr(hir::Expr { hir_id, .. })) => {
match hir.find(hir.get_parent_node(*hir_id)) {
Some(hir::Node::Arm(hir::Arm { pat, .. })) => {
pat.walk(&mut find_compatible_candidates);
}
Some(
hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn(_, _, body), .. })
| hir::Node::ImplItem(hir::ImplItem {
kind: hir::ImplItemKind::Fn(_, body),
..
})
| hir::Node::TraitItem(hir::TraitItem {
kind: hir::TraitItemKind::Fn(_, hir::TraitFn::Provided(body)),
..
})
| hir::Node::Expr(hir::Expr {
kind: hir::ExprKind::Closure(hir::Closure { body, .. }),
..
}),
) => {
for param in hir.body(*body).params {
param.pat.walk(&mut find_compatible_candidates);
}
}
Some(hir::Node::Expr(hir::Expr {
kind:
hir::ExprKind::If(
hir::Expr { kind: hir::ExprKind::Let(let_), .. },
then_block,
_,
),
..
})) if then_block.hir_id == *hir_id => {
let_.pat.walk(&mut find_compatible_candidates);
}
_ => {}
}
}
_ => {}
}
match &candidate_idents[..] {
[(ident, _ty)] => {
let sm = self.tcx.sess.source_map();
if let Some(stmt) = blk.stmts.last() {
let stmt_span = sm.stmt_span(stmt.span, blk.span);
let sugg = if sm.is_multiline(blk.span)
&& let Some(spacing) = sm.indentation_before(stmt_span)
{
format!("\n{spacing}{ident}")
} else {
format!(" {ident}")
};
err.span_suggestion_verbose(
stmt_span.shrink_to_hi(),
format!("consider returning the local binding `{ident}`"),
sugg,
Applicability::MaybeIncorrect,
);
} else {
let sugg = if sm.is_multiline(blk.span)
&& let Some(spacing) = sm.indentation_before(blk.span.shrink_to_lo())
{
format!("\n{spacing} {ident}\n{spacing}")
} else {
format!(" {ident} ")
};
let left_span = sm.span_through_char(blk.span, '{').shrink_to_hi();
err.span_suggestion_verbose(
sm.span_extend_while(left_span, |c| c.is_whitespace()).unwrap_or(left_span),
format!("consider returning the local binding `{ident}`"),
sugg,
Applicability::MaybeIncorrect,
);
}
true
}
values if (1..3).contains(&values.len()) => {
let spans = values.iter().map(|(ident, _)| ident.span).collect::<Vec<_>>();
err.span_note(spans, "consider returning one of these bindings");
true
}
_ => false,
}
}
}