From 831f4549cd1b23915729cbd2f1dd841621c4e8b8 Mon Sep 17 00:00:00 2001
From: uellenberg <JonahUellenberg@hotmail.com>
Date: Mon, 11 Nov 2024 19:20:59 -0800
Subject: [PATCH] Suggest using deref in patterns
Fixes #132784
---
compiler/rustc_hir/src/hir.rs | 16 ++
.../src/fn_ctxt/suggestions.rs | 17 +-
compiler/rustc_hir_typeck/src/pat.rs | 30 +-
compiler/rustc_middle/src/traits/mod.rs | 23 +-
.../src/error_reporting/infer/mod.rs | 115 ++++++--
.../src/error_reporting/infer/suggest.rs | 2 +-
.../src/error_reporting/traits/suggestions.rs | 11 +-
.../2229_closure_analysis/issue-118144.stderr | 5 +
.../issue-57741.stderr | 36 +--
.../let-else/let-else-deref-coercion.stderr | 10 +
.../suggest-deref-in-match-issue-132784.rs | 84 ++++++
...suggest-deref-in-match-issue-132784.stderr | 259 ++++++++++++++++++
12 files changed, 544 insertions(+), 64 deletions(-)
create mode 100644 tests/ui/suggestions/suggest-deref-in-match-issue-132784.rs
create mode 100644 tests/ui/suggestions/suggest-deref-in-match-issue-132784.stderr
diff --git a/compiler/rustc_hir/src/hir.rs b/compiler/rustc_hir/src/hir.rs
index 8cf18c2b912eb..8225b1189a2c4 100644
--- a/compiler/rustc_hir/src/hir.rs
+++ b/compiler/rustc_hir/src/hir.rs
@@ -2020,6 +2020,22 @@ pub fn is_range_literal(expr: &Expr<'_>) -> bool {
}
}
+/// Checks if the specified expression needs parentheses for prefix
+/// or postfix suggestions to be valid.
+/// For example, `a + b` requires parentheses to suggest `&(a + b)`,
+/// but just `a` does not.
+/// Similarly, `(a + b).c()` also requires parentheses.
+/// This should not be used for other types of suggestions.
+pub fn expr_needs_parens(expr: &Expr<'_>) -> bool {
+ match expr.kind {
+ // parenthesize if needed (Issue #46756)
+ ExprKind::Cast(_, _) | ExprKind::Binary(_, _, _) => true,
+ // parenthesize borrows of range literals (Issue #54505)
+ _ if is_range_literal(expr) => true,
+ _ => false,
+ }
+}
+
#[derive(Debug, Clone, Copy, HashStable_Generic)]
pub enum ExprKind<'hir> {
/// Allow anonymous constants from an inline `const` block
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
index ddcd90a2a9da6..21b1768ae6f4d 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
@@ -10,7 +10,7 @@ use rustc_hir::def::{CtorKind, CtorOf, DefKind, Res};
use rustc_hir::lang_items::LangItem;
use rustc_hir::{
Arm, CoroutineDesugaring, CoroutineKind, CoroutineSource, Expr, ExprKind, GenericBound, HirId,
- Node, Path, QPath, Stmt, StmtKind, TyKind, WherePredicateKind,
+ Node, Path, QPath, Stmt, StmtKind, TyKind, WherePredicateKind, expr_needs_parens,
};
use rustc_hir_analysis::collect::suggest_impl_trait;
use rustc_hir_analysis::hir_ty_lowering::HirTyLowerer;
@@ -35,7 +35,6 @@ use tracing::{debug, instrument};
use super::FnCtxt;
use crate::fn_ctxt::rustc_span::BytePos;
-use crate::hir::is_range_literal;
use crate::method::probe;
use crate::method::probe::{IsSuggestion, Mode, ProbeScope};
use crate::{errors, fluent_generated as fluent};
@@ -2648,7 +2647,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
}
let make_sugg = |expr: &Expr<'_>, span: Span, sugg: &str| {
- if self.needs_parentheses(expr) {
+ if expr_needs_parens(expr) {
(
vec![
(span.shrink_to_lo(), format!("{prefix}{sugg}(")),
@@ -2861,7 +2860,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
return None;
}
- if self.needs_parentheses(expr) {
+ if expr_needs_parens(expr) {
return Some((
vec![
(span, format!("{suggestion}(")),
@@ -2902,16 +2901,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
false
}
- fn needs_parentheses(&self, expr: &hir::Expr<'_>) -> bool {
- match expr.kind {
- // parenthesize if needed (Issue #46756)
- hir::ExprKind::Cast(_, _) | hir::ExprKind::Binary(_, _, _) => true,
- // parenthesize borrows of range literals (Issue #54505)
- _ if is_range_literal(expr) => true,
- _ => false,
- }
- }
-
pub(crate) fn suggest_cast(
&self,
err: &mut Diag<'_>,
diff --git a/compiler/rustc_hir_typeck/src/pat.rs b/compiler/rustc_hir_typeck/src/pat.rs
index 2a8ed26aa2bee..e7726845652f3 100644
--- a/compiler/rustc_hir_typeck/src/pat.rs
+++ b/compiler/rustc_hir_typeck/src/pat.rs
@@ -10,8 +10,12 @@ use rustc_errors::{
};
use rustc_hir::def::{CtorKind, DefKind, Res};
use rustc_hir::pat_util::EnumerateAndAdjustIterator;
-use rustc_hir::{self as hir, BindingMode, ByRef, HirId, LangItem, Mutability, Pat, PatKind};
+use rustc_hir::{
+ self as hir, BindingMode, ByRef, ExprKind, HirId, LangItem, Mutability, Pat, PatKind,
+ expr_needs_parens,
+};
use rustc_infer::infer;
+use rustc_middle::traits::PatternOriginExpr;
use rustc_middle::ty::{self, Ty, TypeVisitableExt};
use rustc_middle::{bug, span_bug};
use rustc_session::lint::builtin::NON_EXHAUSTIVE_OMITTED_PATTERNS;
@@ -94,10 +98,32 @@ struct PatInfo<'a, 'tcx> {
impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
fn pattern_cause(&self, ti: &TopInfo<'tcx>, cause_span: Span) -> ObligationCause<'tcx> {
+ // If origin_expr exists, then expected represents the type of origin_expr.
+ // If span also exists, then span == origin_expr.span (although it doesn't need to exist).
+ // In that case, we can peel away references from both and treat them
+ // as the same.
+ let origin_expr_info = ti.origin_expr.map(|mut cur_expr| {
+ let mut count = 0;
+
+ // cur_ty may have more layers of references than cur_expr.
+ // We can only make suggestions about cur_expr, however, so we'll
+ // use that as our condition for stopping.
+ while let ExprKind::AddrOf(.., inner) = &cur_expr.kind {
+ cur_expr = inner;
+ count += 1;
+ }
+
+ PatternOriginExpr {
+ peeled_span: cur_expr.span,
+ peeled_count: count,
+ peeled_prefix_suggestion_parentheses: expr_needs_parens(cur_expr),
+ }
+ });
+
let code = ObligationCauseCode::Pattern {
span: ti.span,
root_ty: ti.expected,
- origin_expr: ti.origin_expr.is_some(),
+ origin_expr: origin_expr_info,
};
self.cause(cause_span, code)
}
diff --git a/compiler/rustc_middle/src/traits/mod.rs b/compiler/rustc_middle/src/traits/mod.rs
index 0a77c3bc42fb9..8c434265d2764 100644
--- a/compiler/rustc_middle/src/traits/mod.rs
+++ b/compiler/rustc_middle/src/traits/mod.rs
@@ -316,8 +316,8 @@ pub enum ObligationCauseCode<'tcx> {
span: Option<Span>,
/// The root expected type induced by a scrutinee or type expression.
root_ty: Ty<'tcx>,
- /// Whether the `Span` came from an expression or a type expression.
- origin_expr: bool,
+ /// Information about the `Span`, if it came from an expression, otherwise `None`.
+ origin_expr: Option<PatternOriginExpr>,
},
/// Computing common supertype in an if expression
@@ -530,6 +530,25 @@ pub struct MatchExpressionArmCause<'tcx> {
pub tail_defines_return_position_impl_trait: Option<LocalDefId>,
}
+/// Information about the origin expression of a pattern, relevant to diagnostics.
+/// Fields here refer to the scrutinee of a pattern.
+/// If the scrutinee isn't given in the diagnostic, then this won't exist.
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+#[derive(TypeFoldable, TypeVisitable, HashStable, TyEncodable, TyDecodable)]
+pub struct PatternOriginExpr {
+ /// A span representing the scrutinee expression, with all leading references
+ /// peeled from the expression.
+ /// Only references in the expression are peeled - if the expression refers to a variable
+ /// whose type is a reference, then that reference is kept because it wasn't created
+ /// in the expression.
+ pub peeled_span: Span,
+ /// The number of references that were peeled to produce `peeled_span`.
+ pub peeled_count: usize,
+ /// Does the peeled expression need to be wrapped in parentheses for
+ /// a prefix suggestion (i.e., dereference) to be valid.
+ pub peeled_prefix_suggestion_parentheses: bool,
+}
+
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
#[derive(TypeFoldable, TypeVisitable, HashStable, TyEncodable, TyDecodable)]
pub struct IfExpressionCause<'tcx> {
diff --git a/compiler/rustc_trait_selection/src/error_reporting/infer/mod.rs b/compiler/rustc_trait_selection/src/error_reporting/infer/mod.rs
index f856a8d7abbe7..5a62a4c3bd5fe 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/infer/mod.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/infer/mod.rs
@@ -63,10 +63,11 @@ use rustc_hir::{self as hir};
use rustc_macros::extension;
use rustc_middle::bug;
use rustc_middle::dep_graph::DepContext;
+use rustc_middle::traits::PatternOriginExpr;
use rustc_middle::ty::error::{ExpectedFound, TypeError, TypeErrorToStringExt};
use rustc_middle::ty::print::{PrintError, PrintTraitRefExt as _, with_forced_trimmed_paths};
use rustc_middle::ty::{
- self, List, Region, Ty, TyCtxt, TypeFoldable, TypeSuperVisitable, TypeVisitable,
+ self, List, ParamEnv, Region, Ty, TyCtxt, TypeFoldable, TypeSuperVisitable, TypeVisitable,
TypeVisitableExt,
};
use rustc_span::def_id::LOCAL_CRATE;
@@ -77,7 +78,7 @@ use crate::error_reporting::TypeErrCtxt;
use crate::errors::{ObligationCauseFailureCode, TypeErrorAdditionalDiags};
use crate::infer;
use crate::infer::relate::{self, RelateResult, TypeRelation};
-use crate::infer::{InferCtxt, TypeTrace, ValuePairs};
+use crate::infer::{InferCtxt, InferCtxtExt as _, TypeTrace, ValuePairs};
use crate::solve::deeply_normalize_for_diagnostics;
use crate::traits::{
IfExpressionCause, MatchExpressionArmCause, ObligationCause, ObligationCauseCode,
@@ -433,15 +434,22 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
cause: &ObligationCause<'tcx>,
exp_found: Option<ty::error::ExpectedFound<Ty<'tcx>>>,
terr: TypeError<'tcx>,
+ param_env: Option<ParamEnv<'tcx>>,
) {
match *cause.code() {
- ObligationCauseCode::Pattern { origin_expr: true, span: Some(span), root_ty } => {
- let ty = self.resolve_vars_if_possible(root_ty);
- if !matches!(ty.kind(), ty::Infer(ty::InferTy::TyVar(_) | ty::InferTy::FreshTy(_)))
- {
+ ObligationCauseCode::Pattern {
+ origin_expr: Some(origin_expr),
+ span: Some(span),
+ root_ty,
+ } => {
+ let expected_ty = self.resolve_vars_if_possible(root_ty);
+ if !matches!(
+ expected_ty.kind(),
+ ty::Infer(ty::InferTy::TyVar(_) | ty::InferTy::FreshTy(_))
+ ) {
// don't show type `_`
if span.desugaring_kind() == Some(DesugaringKind::ForLoop)
- && let ty::Adt(def, args) = ty.kind()
+ && let ty::Adt(def, args) = expected_ty.kind()
&& Some(def.did()) == self.tcx.get_diagnostic_item(sym::Option)
{
err.span_label(
@@ -449,22 +457,48 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
format!("this is an iterator with items of type `{}`", args.type_at(0)),
);
} else {
- err.span_label(span, format!("this expression has type `{ty}`"));
+ err.span_label(span, format!("this expression has type `{expected_ty}`"));
}
}
if let Some(ty::error::ExpectedFound { found, .. }) = exp_found
- && ty.boxed_ty() == Some(found)
- && let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(span)
+ && let Ok(mut peeled_snippet) =
+ self.tcx.sess.source_map().span_to_snippet(origin_expr.peeled_span)
{
- err.span_suggestion(
- span,
- "consider dereferencing the boxed value",
- format!("*{snippet}"),
- Applicability::MachineApplicable,
- );
+ // Parentheses are needed for cases like as casts.
+ // We use the peeled_span for deref suggestions.
+ // It's also safe to use for box, since box only triggers if there
+ // wasn't a reference to begin with.
+ if origin_expr.peeled_prefix_suggestion_parentheses {
+ peeled_snippet = format!("({peeled_snippet})");
+ }
+
+ // Try giving a box suggestion first, as it is a special case of the
+ // deref suggestion.
+ if expected_ty.boxed_ty() == Some(found) {
+ err.span_suggestion_verbose(
+ span,
+ "consider dereferencing the boxed value",
+ format!("*{peeled_snippet}"),
+ Applicability::MachineApplicable,
+ );
+ } else if let Some(param_env) = param_env
+ && let Some(prefix) = self.should_deref_suggestion_on_mismatch(
+ param_env,
+ found,
+ expected_ty,
+ origin_expr,
+ )
+ {
+ err.span_suggestion_verbose(
+ span,
+ "consider dereferencing to access the inner value using the Deref trait",
+ format!("{prefix}{peeled_snippet}"),
+ Applicability::MaybeIncorrect,
+ );
+ }
}
}
- ObligationCauseCode::Pattern { origin_expr: false, span: Some(span), .. } => {
+ ObligationCauseCode::Pattern { origin_expr: None, span: Some(span), .. } => {
err.span_label(span, "expected due to this");
}
ObligationCauseCode::BlockTailExpression(
@@ -618,6 +652,45 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
}
}
+ /// Determines whether deref_to == <deref_from as Deref>::Target, and if so,
+ /// returns a prefix that should be added to deref_from as a suggestion.
+ fn should_deref_suggestion_on_mismatch(
+ &self,
+ param_env: ParamEnv<'tcx>,
+ deref_to: Ty<'tcx>,
+ deref_from: Ty<'tcx>,
+ origin_expr: PatternOriginExpr,
+ ) -> Option<String> {
+ // origin_expr contains stripped away versions of our expression.
+ // We'll want to use that to avoid suggesting things like *&x.
+ // However, the type that we have access to hasn't been stripped away,
+ // so we need to ignore the first n dereferences, where n is the number
+ // that's been stripped away in origin_expr.
+
+ // Find a way to autoderef from deref_from to deref_to.
+ let Some((num_derefs, (after_deref_ty, _))) = (self.autoderef_steps)(deref_from)
+ .into_iter()
+ .enumerate()
+ .find(|(_, (ty, _))| self.infcx.can_eq(param_env, *ty, deref_to))
+ else {
+ return None;
+ };
+
+ if num_derefs <= origin_expr.peeled_count {
+ return None;
+ }
+
+ let deref_part = "*".repeat(num_derefs - origin_expr.peeled_count);
+
+ // If the user used a reference in the original expression, they probably
+ // want the suggestion to still give a reference.
+ if deref_from.is_ref() && !after_deref_ty.is_ref() {
+ Some(format!("&{deref_part}"))
+ } else {
+ Some(deref_part)
+ }
+ }
+
/// Given that `other_ty` is the same as a type argument for `name` in `sub`, populate `value`
/// highlighting `name` and every type argument that isn't at `pos` (which is `other_ty`), and
/// populate `other_value` with `other_ty`.
@@ -1406,8 +1479,8 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
Variable(ty::error::ExpectedFound<Ty<'a>>),
Fixed(&'static str),
}
- let (expected_found, exp_found, is_simple_error, values) = match values {
- None => (None, Mismatch::Fixed("type"), false, None),
+ let (expected_found, exp_found, is_simple_error, values, param_env) = match values {
+ None => (None, Mismatch::Fixed("type"), false, None, None),
Some(ty::ParamEnvAnd { param_env, value: values }) => {
let mut values = self.resolve_vars_if_possible(values);
if self.next_trait_solver() {
@@ -1459,7 +1532,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
diag.downgrade_to_delayed_bug();
return;
};
- (Some(vals), exp_found, is_simple_error, Some(values))
+ (Some(vals), exp_found, is_simple_error, Some(values), Some(param_env))
}
};
@@ -1791,7 +1864,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
// It reads better to have the error origin as the final
// thing.
- self.note_error_origin(diag, cause, exp_found, terr);
+ self.note_error_origin(diag, cause, exp_found, terr, param_env);
debug!(?diag);
}
diff --git a/compiler/rustc_trait_selection/src/error_reporting/infer/suggest.rs b/compiler/rustc_trait_selection/src/error_reporting/infer/suggest.rs
index fc2d0ba36f04e..08775df5ac99a 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/infer/suggest.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/infer/suggest.rs
@@ -210,7 +210,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
(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 {
+ origin_expr.is_some().then_some(ConsiderAddingAwait::FutureSugg {
span: then_span.shrink_to_hi(),
})
}
diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs
index 94682f501a8c4..cc8941b92242d 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs
@@ -20,7 +20,8 @@ use rustc_hir::def_id::DefId;
use rustc_hir::intravisit::Visitor;
use rustc_hir::lang_items::LangItem;
use rustc_hir::{
- CoroutineDesugaring, CoroutineKind, CoroutineSource, Expr, HirId, Node, is_range_literal,
+ CoroutineDesugaring, CoroutineKind, CoroutineSource, Expr, HirId, Node, expr_needs_parens,
+ is_range_literal,
};
use rustc_infer::infer::{BoundRegionConversionTime, DefineOpaqueTypes, InferCtxt, InferOk};
use rustc_middle::hir::map;
@@ -1391,13 +1392,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
let Some(expr) = expr_finder.result else {
return false;
};
- let needs_parens = match expr.kind {
- // parenthesize if needed (Issue #46756)
- hir::ExprKind::Cast(_, _) | hir::ExprKind::Binary(_, _, _) => true,
- // parenthesize borrows of range literals (Issue #54505)
- _ if is_range_literal(expr) => true,
- _ => false,
- };
+ let needs_parens = expr_needs_parens(expr);
let span = if needs_parens { span } else { span.shrink_to_lo() };
let suggestions = if !needs_parens {
diff --git a/tests/ui/closures/2229_closure_analysis/issue-118144.stderr b/tests/ui/closures/2229_closure_analysis/issue-118144.stderr
index 85cb5adc07e90..87084e6023729 100644
--- a/tests/ui/closures/2229_closure_analysis/issue-118144.stderr
+++ b/tests/ui/closures/2229_closure_analysis/issue-118144.stderr
@@ -5,6 +5,11 @@ LL | V(x) = func_arg;
| ^^^^ -------- this expression has type `&mut V`
| |
| expected `&mut V`, found `V`
+ |
+help: consider dereferencing to access the inner value using the Deref trait
+ |
+LL | V(x) = &*func_arg;
+ | ~~~~~~~~~~
error: aborting due to 1 previous error
diff --git a/tests/ui/issues/issue-57741-dereference-boxed-value/issue-57741.stderr b/tests/ui/issues/issue-57741-dereference-boxed-value/issue-57741.stderr
index 38014ecce7574..3c19b68cffbb3 100644
--- a/tests/ui/issues/issue-57741-dereference-boxed-value/issue-57741.stderr
+++ b/tests/ui/issues/issue-57741-dereference-boxed-value/issue-57741.stderr
@@ -2,57 +2,61 @@ error[E0308]: mismatched types
--> $DIR/issue-57741.rs:20:9
|
LL | let y = match x {
- | -
- | |
- | this expression has type `Box<T>`
- | help: consider dereferencing the boxed value: `*x`
+ | - this expression has type `Box<T>`
LL | T::A(a) | T::B(a) => a,
| ^^^^^^^ expected `Box<T>`, found `T`
|
= note: expected struct `Box<T>`
found enum `T`
+help: consider dereferencing the boxed value
+ |
+LL | let y = match *x {
+ | ~~
error[E0308]: mismatched types
--> $DIR/issue-57741.rs:20:19
|
LL | let y = match x {
- | -
- | |
- | this expression has type `Box<T>`
- | help: consider dereferencing the boxed value: `*x`
+ | - this expression has type `Box<T>`
LL | T::A(a) | T::B(a) => a,
| ^^^^^^^ expected `Box<T>`, found `T`
|
= note: expected struct `Box<T>`
found enum `T`
+help: consider dereferencing the boxed value
+ |
+LL | let y = match *x {
+ | ~~
error[E0308]: mismatched types
--> $DIR/issue-57741.rs:27:9
|
LL | let y = match x {
- | -
- | |
- | this expression has type `Box<S>`
- | help: consider dereferencing the boxed value: `*x`
+ | - this expression has type `Box<S>`
LL | S::A { a } | S::B { b: a } => a,
| ^^^^^^^^^^ expected `Box<S>`, found `S`
|
= note: expected struct `Box<S>`
found enum `S`
+help: consider dereferencing the boxed value
+ |
+LL | let y = match *x {
+ | ~~
error[E0308]: mismatched types
--> $DIR/issue-57741.rs:27:22
|
LL | let y = match x {
- | -
- | |
- | this expression has type `Box<S>`
- | help: consider dereferencing the boxed value: `*x`
+ | - this expression has type `Box<S>`
LL | S::A { a } | S::B { b: a } => a,
| ^^^^^^^^^^^^^ expected `Box<S>`, found `S`
|
= note: expected struct `Box<S>`
found enum `S`
+help: consider dereferencing the boxed value
+ |
+LL | let y = match *x {
+ | ~~
error: aborting due to 4 previous errors
diff --git a/tests/ui/let-else/let-else-deref-coercion.stderr b/tests/ui/let-else/let-else-deref-coercion.stderr
index 143b838bac500..da8b1f4c48e97 100644
--- a/tests/ui/let-else/let-else-deref-coercion.stderr
+++ b/tests/ui/let-else/let-else-deref-coercion.stderr
@@ -5,6 +5,11 @@ LL | let Bar::Present(z) = self else {
| ^^^^^^^^^^^^^^^ ---- this expression has type `&mut Foo`
| |
| expected `Foo`, found `Bar`
+ |
+help: consider dereferencing to access the inner value using the Deref trait
+ |
+LL | let Bar::Present(z) = &**self else {
+ | ~~~~~~~
error[E0308]: mismatched types
--> $DIR/let-else-deref-coercion.rs:68:13
@@ -13,6 +18,11 @@ LL | let Bar(z) = x;
| ^^^^^^ - this expression has type `&mut irrefutable::Foo`
| |
| expected `Foo`, found `Bar`
+ |
+help: consider dereferencing to access the inner value using the Deref trait
+ |
+LL | let Bar(z) = &**x;
+ | ~~~~
error: aborting due to 2 previous errors
diff --git a/tests/ui/suggestions/suggest-deref-in-match-issue-132784.rs b/tests/ui/suggestions/suggest-deref-in-match-issue-132784.rs
new file mode 100644
index 0000000000000..205e57f4a9ff5
--- /dev/null
+++ b/tests/ui/suggestions/suggest-deref-in-match-issue-132784.rs
@@ -0,0 +1,84 @@
+use std::sync::Arc;
+fn main() {
+ let mut x = Arc::new(Some(1));
+ match x {
+ //~^ HELP consider dereferencing to access the inner value using the Deref trait
+ //~| HELP consider dereferencing to access the inner value using the Deref trait
+ Some(_) => {}
+ //~^ ERROR mismatched types
+ None => {}
+ //~^ ERROR mismatched types
+ }
+
+ match &x {
+ //~^ HELP consider dereferencing to access the inner value using the Deref trait
+ //~| HELP consider dereferencing to access the inner value using the Deref trait
+ Some(_) => {}
+ //~^ ERROR mismatched types
+ None => {}
+ //~^ ERROR mismatched types
+ }
+
+ let mut y = Box::new(Some(1));
+ match y {
+ //~^ HELP consider dereferencing to access the inner value using the Deref trait
+ //~| HELP consider dereferencing to access the inner value using the Deref trait
+ Some(_) => {}
+ //~^ ERROR mismatched types
+ None => {}
+ //~^ ERROR mismatched types
+ }
+
+ let mut z = Arc::new(Some(1));
+ match z as Arc<Option<i32>> {
+ //~^ HELP consider dereferencing to access the inner value using the Deref trait
+ //~| HELP consider dereferencing to access the inner value using the Deref trait
+ Some(_) => {}
+ //~^ ERROR mismatched types
+ None => {}
+ //~^ ERROR mismatched types
+ }
+
+ let z_const: &Arc<Option<i32>> = &z;
+ match z_const {
+ //~^ HELP consider dereferencing to access the inner value using the Deref trait
+ //~| HELP consider dereferencing to access the inner value using the Deref trait
+ Some(_) => {}
+ //~^ ERROR mismatched types
+ None => {}
+ //~^ ERROR mismatched types
+ }
+
+ // Normal reference because Arc doesn't implement DerefMut.
+ let z_mut: &mut Arc<Option<i32>> = &mut z;
+ match z_mut {
+ //~^ HELP consider dereferencing to access the inner value using the Deref trait
+ //~| HELP consider dereferencing to access the inner value using the Deref trait
+ Some(_) => {}
+ //~^ ERROR mismatched types
+ None => {}
+ //~^ ERROR mismatched types
+ }
+
+ // Mutable reference because Box does implement DerefMut.
+ let y_mut: &mut Box<Option<i32>> = &mut y;
+ match y_mut {
+ //~^ HELP consider dereferencing to access the inner value using the Deref trait
+ //~| HELP consider dereferencing to access the inner value using the Deref trait
+ Some(_) => {}
+ //~^ ERROR mismatched types
+ None => {}
+ //~^ ERROR mismatched types
+ }
+
+ // Difficult expression.
+ let difficult = Arc::new(Some(1));
+ match (& (&difficult) ) {
+ //~^ HELP consider dereferencing to access the inner value using the Deref trait
+ //~| HELP consider dereferencing to access the inner value using the Deref trait
+ Some(_) => {}
+ //~^ ERROR mismatched types
+ None => {}
+ //~^ ERROR mismatched types
+ }
+}
diff --git a/tests/ui/suggestions/suggest-deref-in-match-issue-132784.stderr b/tests/ui/suggestions/suggest-deref-in-match-issue-132784.stderr
new file mode 100644
index 0000000000000..9338ef1908943
--- /dev/null
+++ b/tests/ui/suggestions/suggest-deref-in-match-issue-132784.stderr
@@ -0,0 +1,259 @@
+error[E0308]: mismatched types
+ --> $DIR/suggest-deref-in-match-issue-132784.rs:7:9
+ |
+LL | match x {
+ | - this expression has type `Arc<Option<{integer}>>`
+...
+LL | Some(_) => {}
+ | ^^^^^^^ expected `Arc<Option<{integer}>>`, found `Option<_>`
+ |
+ = note: expected struct `Arc<Option<{integer}>>`
+ found enum `Option<_>`
+help: consider dereferencing to access the inner value using the Deref trait
+ |
+LL | match *x {
+ | ~~
+
+error[E0308]: mismatched types
+ --> $DIR/suggest-deref-in-match-issue-132784.rs:9:9
+ |
+LL | match x {
+ | - this expression has type `Arc<Option<{integer}>>`
+...
+LL | None => {}
+ | ^^^^ expected `Arc<Option<{integer}>>`, found `Option<_>`
+ |
+ = note: expected struct `Arc<Option<{integer}>>`
+ found enum `Option<_>`
+help: consider dereferencing to access the inner value using the Deref trait
+ |
+LL | match *x {
+ | ~~
+
+error[E0308]: mismatched types
+ --> $DIR/suggest-deref-in-match-issue-132784.rs:16:9
+ |
+LL | match &x {
+ | -- this expression has type `&Arc<Option<{integer}>>`
+...
+LL | Some(_) => {}
+ | ^^^^^^^ expected `Arc<Option<{integer}>>`, found `Option<_>`
+ |
+ = note: expected struct `Arc<Option<{integer}>>`
+ found enum `Option<_>`
+help: consider dereferencing to access the inner value using the Deref trait
+ |
+LL | match &*x {
+ | ~~~
+
+error[E0308]: mismatched types
+ --> $DIR/suggest-deref-in-match-issue-132784.rs:18:9
+ |
+LL | match &x {
+ | -- this expression has type `&Arc<Option<{integer}>>`
+...
+LL | None => {}
+ | ^^^^ expected `Arc<Option<{integer}>>`, found `Option<_>`
+ |
+ = note: expected struct `Arc<Option<{integer}>>`
+ found enum `Option<_>`
+help: consider dereferencing to access the inner value using the Deref trait
+ |
+LL | match &*x {
+ | ~~~
+
+error[E0308]: mismatched types
+ --> $DIR/suggest-deref-in-match-issue-132784.rs:26:9
+ |
+LL | match y {
+ | - this expression has type `Box<Option<{integer}>>`
+...
+LL | Some(_) => {}
+ | ^^^^^^^ expected `Box<Option<{integer}>>`, found `Option<_>`
+ |
+ = note: expected struct `Box<Option<{integer}>>`
+ found enum `Option<_>`
+help: consider dereferencing to access the inner value using the Deref trait
+ |
+LL | match *y {
+ | ~~
+
+error[E0308]: mismatched types
+ --> $DIR/suggest-deref-in-match-issue-132784.rs:28:9
+ |
+LL | match y {
+ | - this expression has type `Box<Option<{integer}>>`
+...
+LL | None => {}
+ | ^^^^ expected `Box<Option<{integer}>>`, found `Option<_>`
+ |
+ = note: expected struct `Box<Option<{integer}>>`
+ found enum `Option<_>`
+help: consider dereferencing to access the inner value using the Deref trait
+ |
+LL | match *y {
+ | ~~
+
+error[E0308]: mismatched types
+ --> $DIR/suggest-deref-in-match-issue-132784.rs:36:9
+ |
+LL | match z as Arc<Option<i32>> {
+ | --------------------- this expression has type `Arc<Option<i32>>`
+...
+LL | Some(_) => {}
+ | ^^^^^^^ expected `Arc<Option<i32>>`, found `Option<_>`
+ |
+ = note: expected struct `Arc<Option<i32>>`
+ found enum `Option<_>`
+help: consider dereferencing to access the inner value using the Deref trait
+ |
+LL | match *(z as Arc<Option<i32>>) {
+ | ~~~~~~~~~~~~~~~~~~~~~~~~
+
+error[E0308]: mismatched types
+ --> $DIR/suggest-deref-in-match-issue-132784.rs:38:9
+ |
+LL | match z as Arc<Option<i32>> {
+ | --------------------- this expression has type `Arc<Option<i32>>`
+...
+LL | None => {}
+ | ^^^^ expected `Arc<Option<i32>>`, found `Option<_>`
+ |
+ = note: expected struct `Arc<Option<i32>>`
+ found enum `Option<_>`
+help: consider dereferencing to access the inner value using the Deref trait
+ |
+LL | match *(z as Arc<Option<i32>>) {
+ | ~~~~~~~~~~~~~~~~~~~~~~~~
+
+error[E0308]: mismatched types
+ --> $DIR/suggest-deref-in-match-issue-132784.rs:46:9
+ |
+LL | match z_const {
+ | ------- this expression has type `&Arc<Option<i32>>`
+...
+LL | Some(_) => {}
+ | ^^^^^^^ expected `Arc<Option<i32>>`, found `Option<_>`
+ |
+ = note: expected struct `Arc<Option<i32>>`
+ found enum `Option<_>`
+help: consider dereferencing to access the inner value using the Deref trait
+ |
+LL | match &**z_const {
+ | ~~~~~~~~~~
+
+error[E0308]: mismatched types
+ --> $DIR/suggest-deref-in-match-issue-132784.rs:48:9
+ |
+LL | match z_const {
+ | ------- this expression has type `&Arc<Option<i32>>`
+...
+LL | None => {}
+ | ^^^^ expected `Arc<Option<i32>>`, found `Option<_>`
+ |
+ = note: expected struct `Arc<Option<i32>>`
+ found enum `Option<_>`
+help: consider dereferencing to access the inner value using the Deref trait
+ |
+LL | match &**z_const {
+ | ~~~~~~~~~~
+
+error[E0308]: mismatched types
+ --> $DIR/suggest-deref-in-match-issue-132784.rs:57:9
+ |
+LL | match z_mut {
+ | ----- this expression has type `&mut Arc<Option<i32>>`
+...
+LL | Some(_) => {}
+ | ^^^^^^^ expected `Arc<Option<i32>>`, found `Option<_>`
+ |
+ = note: expected struct `Arc<Option<i32>>`
+ found enum `Option<_>`
+help: consider dereferencing to access the inner value using the Deref trait
+ |
+LL | match &**z_mut {
+ | ~~~~~~~~
+
+error[E0308]: mismatched types
+ --> $DIR/suggest-deref-in-match-issue-132784.rs:59:9
+ |
+LL | match z_mut {
+ | ----- this expression has type `&mut Arc<Option<i32>>`
+...
+LL | None => {}
+ | ^^^^ expected `Arc<Option<i32>>`, found `Option<_>`
+ |
+ = note: expected struct `Arc<Option<i32>>`
+ found enum `Option<_>`
+help: consider dereferencing to access the inner value using the Deref trait
+ |
+LL | match &**z_mut {
+ | ~~~~~~~~
+
+error[E0308]: mismatched types
+ --> $DIR/suggest-deref-in-match-issue-132784.rs:68:9
+ |
+LL | match y_mut {
+ | ----- this expression has type `&mut Box<Option<i32>>`
+...
+LL | Some(_) => {}
+ | ^^^^^^^ expected `Box<Option<i32>>`, found `Option<_>`
+ |
+ = note: expected struct `Box<Option<i32>>`
+ found enum `Option<_>`
+help: consider dereferencing to access the inner value using the Deref trait
+ |
+LL | match &**y_mut {
+ | ~~~~~~~~
+
+error[E0308]: mismatched types
+ --> $DIR/suggest-deref-in-match-issue-132784.rs:70:9
+ |
+LL | match y_mut {
+ | ----- this expression has type `&mut Box<Option<i32>>`
+...
+LL | None => {}
+ | ^^^^ expected `Box<Option<i32>>`, found `Option<_>`
+ |
+ = note: expected struct `Box<Option<i32>>`
+ found enum `Option<_>`
+help: consider dereferencing to access the inner value using the Deref trait
+ |
+LL | match &**y_mut {
+ | ~~~~~~~~
+
+error[E0308]: mismatched types
+ --> $DIR/suggest-deref-in-match-issue-132784.rs:79:9
+ |
+LL | match (& (&difficult) ) {
+ | ------------------ this expression has type `&&Arc<Option<{integer}>>`
+...
+LL | Some(_) => {}
+ | ^^^^^^^ expected `Arc<Option<{integer}>>`, found `Option<_>`
+ |
+ = note: expected struct `Arc<Option<{integer}>>`
+ found enum `Option<_>`
+help: consider dereferencing to access the inner value using the Deref trait
+ |
+LL | match &*difficult {
+ | ~~~~~~~~~~~
+
+error[E0308]: mismatched types
+ --> $DIR/suggest-deref-in-match-issue-132784.rs:81:9
+ |
+LL | match (& (&difficult) ) {
+ | ------------------ this expression has type `&&Arc<Option<{integer}>>`
+...
+LL | None => {}
+ | ^^^^ expected `Arc<Option<{integer}>>`, found `Option<_>`
+ |
+ = note: expected struct `Arc<Option<{integer}>>`
+ found enum `Option<_>`
+help: consider dereferencing to access the inner value using the Deref trait
+ |
+LL | match &*difficult {
+ | ~~~~~~~~~~~
+
+error: aborting due to 16 previous errors
+
+For more information about this error, try `rustc --explain E0308`.