use core::ops::ControlFlow;
use hir::def::CtorKind;
use hir::intravisit::{Visitor, walk_expr, walk_stmt};
use hir::{LetStmt, QPath};
use rustc_data_structures::fx::FxIndexSet;
use rustc_errors::{Applicability, Diag};
use rustc_hir as hir;
use rustc_hir::def::Res;
use rustc_hir::{MatchSource, Node};
use rustc_middle::traits::{
IfExpressionCause, MatchExpressionArmCause, ObligationCause, ObligationCauseCode,
StatementAsExpression,
};
use rustc_middle::ty::print::with_no_trimmed_paths;
use rustc_middle::ty::{self as ty, GenericArgKind, IsSuggestable, Ty, TypeVisitableExt};
use rustc_span::{Span, sym};
use tracing::debug;
use crate::error_reporting::TypeErrCtxt;
use crate::error_reporting::infer::hir::Path;
use crate::errors::{
ConsiderAddingAwait, FnConsiderCasting, FnItemsAreDistinct, FnUniqTypes,
FunctionPointerSuggestion, SuggestAccessingField, SuggestRemoveSemiOrReturnBinding,
SuggestTuplePatternMany, SuggestTuplePatternOne, TypeErrorAdditionalDiags,
};
#[derive(Clone, Copy)]
pub enum SuggestAsRefKind {
Option,
Result,
}
impl<'tcx> TypeErrCtxt<'_, 'tcx> {
pub(super) fn suggest_remove_semi_or_return_binding(
&self,
first_id: Option<hir::HirId>,
first_ty: Ty<'tcx>,
first_span: Span,
second_id: Option<hir::HirId>,
second_ty: Ty<'tcx>,
second_span: Span,
) -> Option<SuggestRemoveSemiOrReturnBinding> {
let remove_semicolon = [
(first_id, self.resolve_vars_if_possible(second_ty)),
(second_id, self.resolve_vars_if_possible(first_ty)),
]
.into_iter()
.find_map(|(id, ty)| {
let hir::Node::Block(blk) = self.tcx.hir_node(id?) else { return None };
self.could_remove_semicolon(blk, ty)
});
match remove_semicolon {
Some((sp, StatementAsExpression::NeedsBoxing)) => {
Some(SuggestRemoveSemiOrReturnBinding::RemoveAndBox {
first_lo: first_span.shrink_to_lo(),
first_hi: first_span.shrink_to_hi(),
second_lo: second_span.shrink_to_lo(),
second_hi: second_span.shrink_to_hi(),
sp,
})
}
Some((sp, StatementAsExpression::CorrectType)) => {
Some(SuggestRemoveSemiOrReturnBinding::Remove { sp })
}
None => {
let mut ret = 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_node(id)
&& let Some(diag) = self.consider_returning_binding_diag(blk, ty)
{
ret = Some(diag);
break;
}
}
ret
}
}
}
pub(super) fn suggest_tuple_pattern(
&self,
cause: &ObligationCause<'tcx>,
exp_found: &ty::error::ExpectedFound<Ty<'tcx>>,
diag: &mut Diag<'_>,
) {
if let ObligationCauseCode::Pattern { .. } = cause.code() {
if let ty::Adt(expected_adt, args) = exp_found.expected.kind() {
let compatible_variants: Vec<_> = expected_adt
.variants()
.iter()
.filter(|variant| {
variant.fields.len() == 1 && variant.ctor_kind() == Some(CtorKind::Fn)
})
.filter_map(|variant| {
let sole_field = &variant.single_field();
let sole_field_ty = sole_field.ty(self.tcx, args);
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));
if let Some(path) = variant_path.strip_prefix("std::prelude::") {
if let Some((_, path)) = path.split_once("::") {
return Some(path.to_string());
}
}
Some(variant_path)
} else {
None
}
})
.collect();
match &compatible_variants[..] {
[] => {}
[variant] => {
let sugg = SuggestTuplePatternOne {
variant: variant.to_owned(),
span_low: cause.span.shrink_to_lo(),
span_high: cause.span.shrink_to_hi(),
};
diag.subdiagnostic(sugg);
}
_ => {
let sugg = SuggestTuplePatternMany {
path: self.tcx.def_path_str(expected_adt.did()),
cause_span: cause.span,
compatible_variants,
};
diag.subdiagnostic(sugg);
}
}
}
}
}
pub(super) fn suggest_await_on_expect_found(
&self,
cause: &ObligationCause<'tcx>,
exp_span: Span,
exp_found: &ty::error::ExpectedFound<Ty<'tcx>>,
diag: &mut Diag<'_>,
) {
debug!(
"suggest_await_on_expect_found: exp_span={:?}, expected_ty={:?}, found_ty={:?}",
exp_span, exp_found.expected, exp_found.found,
);
if let ObligationCauseCode::CompareImplItem { .. } = cause.code() {
return;
}
let subdiag = match (
self.get_impl_future_output_ty(exp_found.expected),
self.get_impl_future_output_ty(exp_found.found),
) {
(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);
Some(ConsiderAddingAwait::BothFuturesSugg {
first: then_span.shrink_to_hi(),
second: exp_span.shrink_to_hi(),
})
}
ObligationCauseCode::MatchExpressionArm(box MatchExpressionArmCause {
prior_non_diverging_arms,
..
}) => {
if let [.., arm_span] = &prior_non_diverging_arms[..] {
Some(ConsiderAddingAwait::BothFuturesSugg {
first: arm_span.shrink_to_hi(),
second: exp_span.shrink_to_hi(),
})
} else {
Some(ConsiderAddingAwait::BothFuturesHelp)
}
}
_ => Some(ConsiderAddingAwait::BothFuturesHelp),
},
(_, Some(ty)) if self.same_type_modulo_infer(exp_found.expected, ty) => {
diag.subdiagnostic(ConsiderAddingAwait::FutureSugg {
span: exp_span.shrink_to_hi(),
});
Some(ConsiderAddingAwait::FutureSuggNote { span: exp_span })
}
(Some(ty), _) if self.same_type_modulo_infer(ty, exp_found.found) => match cause.code()
{
ObligationCauseCode::Pattern { span: Some(then_span), origin_expr, .. } => {
origin_expr.then_some(ConsiderAddingAwait::FutureSugg {
span: then_span.shrink_to_hi(),
})
}
ObligationCauseCode::IfExpression(box IfExpressionCause { then_id, .. }) => {
let then_span = self.find_block_span_from_hir_id(*then_id);
Some(ConsiderAddingAwait::FutureSugg { span: then_span.shrink_to_hi() })
}
ObligationCauseCode::MatchExpressionArm(box MatchExpressionArmCause {
ref prior_non_diverging_arms,
..
}) => Some({
ConsiderAddingAwait::FutureSuggMultiple {
spans: prior_non_diverging_arms
.iter()
.map(|arm| arm.shrink_to_hi())
.collect(),
}
}),
_ => None,
},
_ => None,
};
if let Some(subdiag) = subdiag {
diag.subdiagnostic(subdiag);
}
}
pub(super) fn suggest_accessing_field_where_appropriate(
&self,
cause: &ObligationCause<'tcx>,
exp_found: &ty::error::ExpectedFound<Ty<'tcx>>,
diag: &mut Diag<'_>,
) {
debug!(
"suggest_accessing_field_where_appropriate(cause={:?}, exp_found={:?})",
cause, exp_found
);
if let ty::Adt(expected_def, expected_args) = exp_found.expected.kind() {
if expected_def.is_enum() {
return;
}
if let Some((name, ty)) = expected_def
.non_enum_variant()
.fields
.iter()
.filter(|field| field.vis.is_accessible_from(field.did, self.tcx))
.map(|field| (field.name, field.ty(self.tcx, expected_args)))
.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) {
let suggestion = if expected_def.is_struct() {
SuggestAccessingField::Safe { span, snippet, name, ty }
} else if expected_def.is_union() {
SuggestAccessingField::Unsafe { span, snippet, name, ty }
} else {
return;
};
diag.subdiagnostic(suggestion);
}
}
}
}
}
pub(super) fn suggest_turning_stmt_into_expr(
&self,
cause: &ObligationCause<'tcx>,
exp_found: &ty::error::ExpectedFound<Ty<'tcx>>,
diag: &mut Diag<'_>,
) {
let ty::error::ExpectedFound { expected, found } = exp_found;
if !found.peel_refs().is_unit() {
return;
}
let ObligationCauseCode::BlockTailExpression(hir_id, MatchSource::Normal) = cause.code()
else {
return;
};
let node = self.tcx.hir_node(*hir_id);
let mut blocks = vec![];
if let hir::Node::Block(block) = node
&& let Some(expr) = block.expr
&& let hir::ExprKind::Path(QPath::Resolved(_, Path { res, .. })) = expr.kind
&& let Res::Local(local) = res
&& let Node::LetStmt(LetStmt { init: Some(init), .. }) =
self.tcx.parent_hir_node(*local)
{
fn collect_blocks<'hir>(expr: &hir::Expr<'hir>, blocks: &mut Vec<&hir::Block<'hir>>) {
match expr.kind {
hir::ExprKind::If(_, blk1, Some(blk2)) => {
collect_blocks(blk1, blocks);
collect_blocks(blk2, blocks);
}
hir::ExprKind::Match(_, arms, _) => {
for arm in arms.iter() {
collect_blocks(arm.body, blocks);
}
}
hir::ExprKind::Block(blk, _) => {
blocks.push(blk);
}
_ => {}
}
}
collect_blocks(init, &mut blocks);
}
let expected_inner: Ty<'_> = expected.peel_refs();
for block in blocks.iter() {
self.consider_removing_semicolon(block, expected_inner, diag);
}
}
pub fn consider_removing_semicolon(
&self,
blk: &'tcx hir::Block<'tcx>,
expected_ty: Ty<'tcx>,
diag: &mut Diag<'_>,
) -> bool {
if let Some((span_semi, boxed)) = self.could_remove_semicolon(blk, expected_ty) {
if let StatementAsExpression::NeedsBoxing = boxed {
diag.span_suggestion_verbose(
span_semi,
"consider removing this semicolon and boxing the expression",
"",
Applicability::HasPlaceholders,
);
} else {
diag.span_suggestion_short(
span_semi,
"remove this semicolon to return this value",
"",
Applicability::MachineApplicable,
);
}
true
} else {
false
}
}
pub(super) fn suggest_function_pointers(
&self,
cause: &ObligationCause<'tcx>,
span: Span,
exp_found: &ty::error::ExpectedFound<Ty<'tcx>>,
diag: &mut Diag<'_>,
) {
debug!("suggest_function_pointers(cause={:?}, exp_found={:?})", cause, exp_found);
let ty::error::ExpectedFound { expected, found } = exp_found;
let expected_inner = expected.peel_refs();
let found_inner = found.peel_refs();
if !expected_inner.is_fn() || !found_inner.is_fn() {
return;
}
match (expected_inner.kind(), found_inner.kind()) {
(ty::FnPtr(sig_tys, hdr), ty::FnDef(did, args)) => {
let sig = sig_tys.with(*hdr);
let expected_sig = &(self.normalize_fn_sig)(sig);
let found_sig =
&(self.normalize_fn_sig)(self.tcx.fn_sig(*did).instantiate(self.tcx, args));
let fn_name = self.tcx.def_path_str_with_args(*did, args);
if !self.same_type_modulo_infer(*found_sig, *expected_sig)
|| !sig.is_suggestable(self.tcx, true)
|| self.tcx.intrinsic(*did).is_some()
{
return;
}
let sugg = match (expected.is_ref(), found.is_ref()) {
(true, false) => FunctionPointerSuggestion::UseRef { span, fn_name },
(false, true) => FunctionPointerSuggestion::RemoveRef { span, fn_name },
(true, true) => {
diag.subdiagnostic(FnItemsAreDistinct);
FunctionPointerSuggestion::CastRef { span, fn_name, sig }
}
(false, false) => {
diag.subdiagnostic(FnItemsAreDistinct);
FunctionPointerSuggestion::Cast { span, fn_name, sig }
}
};
diag.subdiagnostic(sugg);
}
(ty::FnDef(did1, args1), ty::FnDef(did2, args2)) => {
let expected_sig =
&(self.normalize_fn_sig)(self.tcx.fn_sig(*did1).instantiate(self.tcx, args1));
let found_sig =
&(self.normalize_fn_sig)(self.tcx.fn_sig(*did2).instantiate(self.tcx, args2));
if self.same_type_modulo_infer(*expected_sig, *found_sig) {
diag.subdiagnostic(FnUniqTypes);
}
if !self.same_type_modulo_infer(*found_sig, *expected_sig)
|| !found_sig.is_suggestable(self.tcx, true)
|| !expected_sig.is_suggestable(self.tcx, true)
|| self.tcx.intrinsic(*did1).is_some()
|| self.tcx.intrinsic(*did2).is_some()
{
return;
}
let fn_name = self.tcx.def_path_str_with_args(*did2, args2);
let sug = if found.is_ref() {
FunctionPointerSuggestion::CastBothRef {
span,
fn_name,
found_sig: *found_sig,
expected_sig: *expected_sig,
}
} else {
FunctionPointerSuggestion::CastBoth {
span,
fn_name,
found_sig: *found_sig,
expected_sig: *expected_sig,
}
};
diag.subdiagnostic(sug);
}
(ty::FnDef(did, args), ty::FnPtr(sig_tys, hdr)) => {
let expected_sig =
&(self.normalize_fn_sig)(self.tcx.fn_sig(*did).instantiate(self.tcx, args));
let found_sig = &(self.normalize_fn_sig)(sig_tys.with(*hdr));
if !self.same_type_modulo_infer(*found_sig, *expected_sig) {
return;
}
let fn_name = self.tcx.def_path_str_with_args(*did, args);
let casting = if expected.is_ref() {
format!("&({fn_name} as {found_sig})")
} else {
format!("{fn_name} as {found_sig}")
};
diag.subdiagnostic(FnConsiderCasting { casting });
}
_ => {
return;
}
};
}
pub fn should_suggest_as_ref_kind(
&self,
expected: Ty<'tcx>,
found: Ty<'tcx>,
) -> Option<SuggestAsRefKind> {
if let (ty::Adt(exp_def, exp_args), ty::Ref(_, found_ty, _)) =
(expected.kind(), found.kind())
{
if let ty::Adt(found_def, found_args) = *found_ty.kind() {
if exp_def == &found_def {
let have_as_ref = &[
(sym::Option, SuggestAsRefKind::Option),
(sym::Result, SuggestAsRefKind::Result),
];
if let Some(msg) = have_as_ref.iter().find_map(|(name, msg)| {
self.tcx.is_diagnostic_item(*name, exp_def.did()).then_some(msg)
}) {
let mut show_suggestion = true;
for (exp_ty, found_ty) in
std::iter::zip(exp_args.types(), found_args.types())
{
match *exp_ty.kind() {
ty::Ref(_, exp_ty, _) => {
match (exp_ty.kind(), found_ty.kind()) {
(_, ty::Param(_))
| (_, ty::Infer(_))
| (ty::Param(_), _)
| (ty::Infer(_), _) => {}
_ if self.same_type_modulo_infer(exp_ty, found_ty) => {}
_ => show_suggestion = false,
};
}
ty::Param(_) | ty::Infer(_) => {}
_ => show_suggestion = false,
}
}
if show_suggestion {
return Some(*msg);
}
}
}
}
}
None
}
pub fn should_suggest_as_ref(&self, expected: Ty<'tcx>, found: Ty<'tcx>) -> Option<&str> {
match self.should_suggest_as_ref_kind(expected, found) {
Some(SuggestAsRefKind::Option) => Some(
"you can convert from `&Option<T>` to `Option<&T>` using \
`.as_ref()`",
),
Some(SuggestAsRefKind::Result) => Some(
"you can convert from `&Result<T, E>` to \
`Result<&T, &E>` using `.as_ref()`",
),
None => None,
}
}
pub(super) fn suggest_let_for_letchains(
&self,
cause: &ObligationCause<'_>,
span: Span,
) -> Option<TypeErrorAdditionalDiags> {
struct IfVisitor {
pub found_if: bool,
pub err_span: Span,
}
impl<'v> Visitor<'v> for IfVisitor {
type Result = ControlFlow<()>;
fn visit_expr(&mut self, ex: &'v hir::Expr<'v>) -> Self::Result {
match ex.kind {
hir::ExprKind::If(cond, _, _) => {
self.found_if = true;
walk_expr(self, cond)?;
self.found_if = false;
ControlFlow::Continue(())
}
_ => walk_expr(self, ex),
}
}
fn visit_stmt(&mut self, ex: &'v hir::Stmt<'v>) -> Self::Result {
if let hir::StmtKind::Let(LetStmt {
span,
pat: hir::Pat { .. },
ty: None,
init: Some(_),
..
}) = &ex.kind
&& self.found_if
&& span.eq(&self.err_span)
{
ControlFlow::Break(())
} else {
walk_stmt(self, ex)
}
}
}
self.tcx.hir().maybe_body_owned_by(cause.body_id).and_then(|body| {
IfVisitor { err_span: span, found_if: false }
.visit_body(&body)
.is_break()
.then(|| TypeErrorAdditionalDiags::AddLetForLetChains { span: span.shrink_to_lo() })
})
}
pub(super) fn suggest_for_all_lifetime_closure(
&self,
span: Span,
hir: hir::Node<'_>,
exp_found: &ty::error::ExpectedFound<ty::TraitRef<'tcx>>,
diag: &mut Diag<'_>,
) {
let hir::Node::Expr(hir::Expr {
kind: hir::ExprKind::Closure(hir::Closure { body, fn_decl, .. }),
..
}) = hir
else {
return;
};
let hir::Body { params, .. } = self.tcx.hir().body(*body);
let Some(expected) = exp_found.expected.args.get(1) else {
return;
};
let Some(found) = exp_found.found.args.get(1) else {
return;
};
let expected = expected.unpack();
let found = found.unpack();
if let GenericArgKind::Type(expected) = expected
&& let GenericArgKind::Type(found) = found
&& let ty::Tuple(expected) = expected.kind()
&& let ty::Tuple(found) = found.kind()
&& expected.len() == found.len()
{
let mut suggestion = "|".to_string();
let mut is_first = true;
let mut has_suggestion = false;
for (((expected, found), param_hir), arg_hir) in
expected.iter().zip(found.iter()).zip(params.iter()).zip(fn_decl.inputs.iter())
{
if is_first {
is_first = false;
} else {
suggestion += ", ";
}
if let ty::Ref(expected_region, _, _) = expected.kind()
&& let ty::Ref(found_region, _, _) = found.kind()
&& expected_region.is_bound()
&& !found_region.is_bound()
&& let hir::TyKind::Infer = arg_hir.kind
{
if param_hir.pat.span == param_hir.ty_span {
let Ok(pat) =
self.tcx.sess.source_map().span_to_snippet(param_hir.pat.span)
else {
return;
};
suggestion += &format!("{pat}: &_");
} else {
let Ok(pat) =
self.tcx.sess.source_map().span_to_snippet(param_hir.pat.span)
else {
return;
};
let Ok(ty) = self.tcx.sess.source_map().span_to_snippet(param_hir.ty_span)
else {
return;
};
suggestion += &format!("{pat}: &{ty}");
}
has_suggestion = true;
} else {
let Ok(arg) = self.tcx.sess.source_map().span_to_snippet(param_hir.span) else {
return;
};
suggestion += &arg;
}
}
suggestion += "|";
if has_suggestion {
diag.span_suggestion_verbose(
span,
"consider specifying the type of the closure parameters",
suggestion,
Applicability::MaybeIncorrect,
);
}
}
}
}
impl<'tcx> TypeErrCtxt<'_, 'tcx> {
pub fn could_remove_semicolon(
&self,
blk: &'tcx hir::Block<'tcx>,
expected_ty: Ty<'tcx>,
) -> Option<(Span, StatementAsExpression)> {
let blk = blk.innermost_block();
if blk.expr.is_some() {
return None;
}
let last_stmt = blk.stmts.last()?;
let hir::StmtKind::Semi(last_expr) = last_stmt.kind else {
return None;
};
let last_expr_ty = self.typeck_results.as_ref()?.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::Alias(ty::Opaque, ty::AliasTy { def_id: last_def_id, .. }),
ty::Alias(ty::Opaque, ty::AliasTy { def_id: exp_def_id, .. }),
) if last_def_id == exp_def_id => StatementAsExpression::CorrectType,
(
ty::Alias(ty::Opaque, ty::AliasTy { def_id: last_def_id, args: last_bounds, .. }),
ty::Alias(ty::Opaque, ty::AliasTy { def_id: exp_def_id, args: 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_opaque_ty(last_local_id),
&self.tcx.hir().expect_opaque_ty(exp_local_id),
) {
(
hir::OpaqueTy { bounds: last_bounds, .. },
hir::OpaqueTy { bounds: exp_bounds, .. },
) if std::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
}
_ => 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 {
self.tcx
.sess
.source_map()
.span_extend_while_whitespace(last_expr.span)
.shrink_to_hi()
.with_hi(last_stmt.span.hi())
};
Some((span, needs_box))
}
pub fn consider_returning_binding_diag(
&self,
blk: &'tcx hir::Block<'tcx>,
expected_ty: Ty<'tcx>,
) -> Option<SuggestRemoveSemiOrReturnBinding> {
let blk = blk.innermost_block();
if blk.expr.is_some() {
return None;
}
let mut shadowed = FxIndexSet::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
.typeck_results
.as_ref()
.and_then(|typeck_results| typeck_results.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::Let(local) = &stmt.kind else {
continue;
};
local.pat.walk(&mut find_compatible_candidates);
}
match self.tcx.parent_hir_node(blk.hir_id) {
hir::Node::Expr(hir::Expr { hir_id, .. }) => match self.tcx.parent_hir_node(*hir_id) {
hir::Node::Arm(hir::Arm { pat, .. }) => {
pat.walk(&mut find_compatible_candidates);
}
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);
}
}
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();
let (span, sugg) = 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}")
};
(stmt_span.shrink_to_hi(), sugg)
} 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();
(sm.span_extend_while_whitespace(left_span), sugg)
};
Some(SuggestRemoveSemiOrReturnBinding::Add { sp: span, code: sugg, ident: *ident })
}
values if (1..3).contains(&values.len()) => {
let spans = values.iter().map(|(ident, _)| ident.span).collect::<Vec<_>>();
Some(SuggestRemoveSemiOrReturnBinding::AddOne { spans: spans.into() })
}
_ => None,
}
}
pub fn consider_returning_binding(
&self,
blk: &'tcx hir::Block<'tcx>,
expected_ty: Ty<'tcx>,
err: &mut Diag<'_>,
) -> bool {
let diag = self.consider_returning_binding_diag(blk, expected_ty);
match diag {
Some(diag) => {
err.subdiagnostic(diag);
true
}
None => false,
}
}
}