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-rw-r--r--crates/hir_def/src/data.rs17
-rw-r--r--crates/hir_ty/src/diagnostics/expr.rs23
-rw-r--r--crates/hir_ty/src/diagnostics/match_check.rs28
-rw-r--r--crates/hir_ty/src/diagnostics/match_check/usefulness.rs5
-rw-r--r--crates/hir_ty/src/infer.rs2
-rw-r--r--crates/hir_ty/src/infer/pat.rs7
-rw-r--r--crates/hir_ty/src/method_resolution.rs16
-rw-r--r--crates/hir_ty/src/tests/method_resolution.rs49
8 files changed, 130 insertions, 17 deletions
diff --git a/crates/hir_def/src/data.rs b/crates/hir_def/src/data.rs
index d2bb381be..52cb7777b 100644
--- a/crates/hir_def/src/data.rs
+++ b/crates/hir_def/src/data.rs
@@ -143,6 +143,10 @@ pub struct TraitData {
143 pub is_auto: bool, 143 pub is_auto: bool,
144 pub is_unsafe: bool, 144 pub is_unsafe: bool,
145 pub visibility: RawVisibility, 145 pub visibility: RawVisibility,
146 /// Whether the trait has `#[rust_skip_array_during_method_dispatch]`. `hir_ty` will ignore
147 /// method calls to this trait's methods when the receiver is an array and the crate edition is
148 /// 2015 or 2018.
149 pub skip_array_during_method_dispatch: bool,
146} 150}
147 151
148impl TraitData { 152impl TraitData {
@@ -157,6 +161,10 @@ impl TraitData {
157 let container = AssocContainerId::TraitId(tr); 161 let container = AssocContainerId::TraitId(tr);
158 let visibility = item_tree[tr_def.visibility].clone(); 162 let visibility = item_tree[tr_def.visibility].clone();
159 let mut expander = Expander::new(db, tr_loc.id.file_id(), module_id); 163 let mut expander = Expander::new(db, tr_loc.id.file_id(), module_id);
164 let skip_array_during_method_dispatch = item_tree
165 .attrs(db, tr_loc.container.krate(), ModItem::from(tr_loc.id.value).into())
166 .by_key("rustc_skip_array_during_method_dispatch")
167 .exists();
160 168
161 let items = collect_items( 169 let items = collect_items(
162 db, 170 db,
@@ -168,7 +176,14 @@ impl TraitData {
168 100, 176 100,
169 ); 177 );
170 178
171 Arc::new(TraitData { name, items, is_auto, is_unsafe, visibility }) 179 Arc::new(TraitData {
180 name,
181 items,
182 is_auto,
183 is_unsafe,
184 visibility,
185 skip_array_during_method_dispatch,
186 })
172 } 187 }
173 188
174 pub fn associated_types(&self) -> impl Iterator<Item = TypeAliasId> + '_ { 189 pub fn associated_types(&self) -> impl Iterator<Item = TypeAliasId> + '_ {
diff --git a/crates/hir_ty/src/diagnostics/expr.rs b/crates/hir_ty/src/diagnostics/expr.rs
index 3efbce773..a2a4d61db 100644
--- a/crates/hir_ty/src/diagnostics/expr.rs
+++ b/crates/hir_ty/src/diagnostics/expr.rs
@@ -357,17 +357,20 @@ impl<'a, 'b> ExprValidator<'a, 'b> {
357 infer: &infer, 357 infer: &infer,
358 db, 358 db,
359 pattern_arena: &pattern_arena, 359 pattern_arena: &pattern_arena,
360 eprint_panic_context: &|| { 360 panic_context: &|| {
361 use syntax::AstNode; 361 use syntax::AstNode;
362 if let Ok(scrutinee_sptr) = source_map.expr_syntax(match_expr) { 362 let match_expr_text = source_map
363 let root = scrutinee_sptr.file_syntax(db.upcast()); 363 .expr_syntax(match_expr)
364 if let Some(match_ast) = scrutinee_sptr.value.to_node(&root).syntax().parent() { 364 .ok()
365 eprintln!( 365 .and_then(|scrutinee_sptr| {
366 "Match checking is about to panic on this expression:\n{}", 366 let root = scrutinee_sptr.file_syntax(db.upcast());
367 match_ast.to_string(), 367 scrutinee_sptr.value.to_node(&root).syntax().parent()
368 ); 368 })
369 } 369 .map(|node| node.to_string());
370 } 370 format!(
371 "expression:\n{}",
372 match_expr_text.as_deref().unwrap_or("<synthesized expr>")
373 )
371 }, 374 },
372 }; 375 };
373 let report = compute_match_usefulness(&cx, &m_arms); 376 let report = compute_match_usefulness(&cx, &m_arms);
diff --git a/crates/hir_ty/src/diagnostics/match_check.rs b/crates/hir_ty/src/diagnostics/match_check.rs
index a9a99f57a..c8e1b23de 100644
--- a/crates/hir_ty/src/diagnostics/match_check.rs
+++ b/crates/hir_ty/src/diagnostics/match_check.rs
@@ -100,10 +100,19 @@ impl<'a> PatCtxt<'a> {
100 } 100 }
101 101
102 pub(crate) fn lower_pattern(&mut self, pat: hir_def::expr::PatId) -> Pat { 102 pub(crate) fn lower_pattern(&mut self, pat: hir_def::expr::PatId) -> Pat {
103 // FIXME: implement pattern adjustments (implicit pattern dereference; "RFC 2005-match-ergonomics") 103 // XXX(iDawer): Collecting pattern adjustments feels imprecise to me.
104 // When lowering of & and box patterns are implemented this should be tested
105 // in a manner of `match_ergonomics_issue_9095` test.
106 // Pattern adjustment is part of RFC 2005-match-ergonomics.
104 // More info https://github.com/rust-lang/rust/issues/42640#issuecomment-313535089 107 // More info https://github.com/rust-lang/rust/issues/42640#issuecomment-313535089
105 let unadjusted_pat = self.lower_pattern_unadjusted(pat); 108 let unadjusted_pat = self.lower_pattern_unadjusted(pat);
106 unadjusted_pat 109 self.infer.pat_adjustments.get(&pat).map(|it| &**it).unwrap_or_default().iter().rev().fold(
110 unadjusted_pat,
111 |subpattern, ref_ty| Pat {
112 ty: ref_ty.clone(),
113 kind: Box::new(PatKind::Deref { subpattern }),
114 },
115 )
107 } 116 }
108 117
109 fn lower_pattern_unadjusted(&mut self, pat: hir_def::expr::PatId) -> Pat { 118 fn lower_pattern_unadjusted(&mut self, pat: hir_def::expr::PatId) -> Pat {
@@ -1236,6 +1245,21 @@ fn main(f: Foo) {
1236 ); 1245 );
1237 } 1246 }
1238 1247
1248 #[test]
1249 fn match_ergonomics_issue_9095() {
1250 check_diagnostics(
1251 r#"
1252enum Foo<T> { A(T) }
1253fn main() {
1254 match &Foo::A(true) {
1255 _ => {}
1256 Foo::A(_) => {}
1257 }
1258}
1259"#,
1260 );
1261 }
1262
1239 mod false_negatives { 1263 mod false_negatives {
1240 //! The implementation of match checking here is a work in progress. As we roll this out, we 1264 //! The implementation of match checking here is a work in progress. As we roll this out, we
1241 //! prefer false negatives to false positives (ideally there would be no false positives). This 1265 //! prefer false negatives to false positives (ideally there would be no false positives). This
diff --git a/crates/hir_ty/src/diagnostics/match_check/usefulness.rs b/crates/hir_ty/src/diagnostics/match_check/usefulness.rs
index 83b094a89..bd76a606c 100644
--- a/crates/hir_ty/src/diagnostics/match_check/usefulness.rs
+++ b/crates/hir_ty/src/diagnostics/match_check/usefulness.rs
@@ -295,7 +295,7 @@ pub(crate) struct MatchCheckCtx<'a> {
295 pub(crate) db: &'a dyn HirDatabase, 295 pub(crate) db: &'a dyn HirDatabase,
296 /// Lowered patterns from arms plus generated by the check. 296 /// Lowered patterns from arms plus generated by the check.
297 pub(crate) pattern_arena: &'a RefCell<PatternArena>, 297 pub(crate) pattern_arena: &'a RefCell<PatternArena>,
298 pub(crate) eprint_panic_context: &'a dyn Fn(), 298 pub(crate) panic_context: &'a dyn Fn() -> String,
299} 299}
300 300
301impl<'a> MatchCheckCtx<'a> { 301impl<'a> MatchCheckCtx<'a> {
@@ -331,8 +331,7 @@ impl<'a> MatchCheckCtx<'a> {
331 331
332 #[track_caller] 332 #[track_caller]
333 pub(super) fn bug(&self, info: &str) -> ! { 333 pub(super) fn bug(&self, info: &str) -> ! {
334 (self.eprint_panic_context)(); 334 panic!("bug: {}\n{}", info, (self.panic_context)());
335 panic!("bug: {}", info);
336 } 335 }
337} 336}
338 337
diff --git a/crates/hir_ty/src/infer.rs b/crates/hir_ty/src/infer.rs
index 7a4268819..0e9f777da 100644
--- a/crates/hir_ty/src/infer.rs
+++ b/crates/hir_ty/src/infer.rs
@@ -150,6 +150,8 @@ pub struct InferenceResult {
150 type_mismatches: FxHashMap<ExprOrPatId, TypeMismatch>, 150 type_mismatches: FxHashMap<ExprOrPatId, TypeMismatch>,
151 /// Interned Unknown to return references to. 151 /// Interned Unknown to return references to.
152 standard_types: InternedStandardTypes, 152 standard_types: InternedStandardTypes,
153 /// Stores the types which were implicitly dereferenced in pattern binding modes.
154 pub pat_adjustments: FxHashMap<PatId, Vec<Ty>>,
153} 155}
154 156
155impl InferenceResult { 157impl InferenceResult {
diff --git a/crates/hir_ty/src/infer/pat.rs b/crates/hir_ty/src/infer/pat.rs
index c97b49544..25dff7e49 100644
--- a/crates/hir_ty/src/infer/pat.rs
+++ b/crates/hir_ty/src/infer/pat.rs
@@ -101,7 +101,9 @@ impl<'a> InferenceContext<'a> {
101 let mut expected = self.resolve_ty_shallow(expected); 101 let mut expected = self.resolve_ty_shallow(expected);
102 102
103 if is_non_ref_pat(&body, pat) { 103 if is_non_ref_pat(&body, pat) {
104 let mut pat_adjustments = Vec::new();
104 while let Some((inner, _lifetime, mutability)) = expected.as_reference() { 105 while let Some((inner, _lifetime, mutability)) = expected.as_reference() {
106 pat_adjustments.push(expected.clone());
105 expected = self.resolve_ty_shallow(inner); 107 expected = self.resolve_ty_shallow(inner);
106 default_bm = match default_bm { 108 default_bm = match default_bm {
107 BindingMode::Move => BindingMode::Ref(mutability), 109 BindingMode::Move => BindingMode::Ref(mutability),
@@ -109,6 +111,11 @@ impl<'a> InferenceContext<'a> {
109 BindingMode::Ref(Mutability::Mut) => BindingMode::Ref(mutability), 111 BindingMode::Ref(Mutability::Mut) => BindingMode::Ref(mutability),
110 } 112 }
111 } 113 }
114
115 if !pat_adjustments.is_empty() {
116 pat_adjustments.shrink_to_fit();
117 self.result.pat_adjustments.insert(pat, pat_adjustments);
118 }
112 } else if let Pat::Ref { .. } = &body[pat] { 119 } else if let Pat::Ref { .. } = &body[pat] {
113 cov_mark::hit!(match_ergonomics_ref); 120 cov_mark::hit!(match_ergonomics_ref);
114 // When you encounter a `&pat` pattern, reset to Move. 121 // When you encounter a `&pat` pattern, reset to Move.
diff --git a/crates/hir_ty/src/method_resolution.rs b/crates/hir_ty/src/method_resolution.rs
index af6b6cda7..a23527f7d 100644
--- a/crates/hir_ty/src/method_resolution.rs
+++ b/crates/hir_ty/src/method_resolution.rs
@@ -5,7 +5,7 @@
5use std::{iter, sync::Arc}; 5use std::{iter, sync::Arc};
6 6
7use arrayvec::ArrayVec; 7use arrayvec::ArrayVec;
8use base_db::CrateId; 8use base_db::{CrateId, Edition};
9use chalk_ir::{cast::Cast, Mutability, UniverseIndex}; 9use chalk_ir::{cast::Cast, Mutability, UniverseIndex};
10use hir_def::{ 10use hir_def::{
11 lang_item::LangItemTarget, nameres::DefMap, AssocContainerId, AssocItemId, FunctionId, 11 lang_item::LangItemTarget, nameres::DefMap, AssocContainerId, AssocItemId, FunctionId,
@@ -639,6 +639,7 @@ fn iterate_trait_method_candidates(
639 receiver_ty: Option<&Canonical<Ty>>, 639 receiver_ty: Option<&Canonical<Ty>>,
640 callback: &mut dyn FnMut(&Ty, AssocItemId) -> bool, 640 callback: &mut dyn FnMut(&Ty, AssocItemId) -> bool,
641) -> bool { 641) -> bool {
642 let receiver_is_array = matches!(self_ty.value.kind(&Interner), chalk_ir::TyKind::Array(..));
642 // if ty is `dyn Trait`, the trait doesn't need to be in scope 643 // if ty is `dyn Trait`, the trait doesn't need to be in scope
643 let inherent_trait = 644 let inherent_trait =
644 self_ty.value.dyn_trait().into_iter().flat_map(|t| all_super_traits(db.upcast(), t)); 645 self_ty.value.dyn_trait().into_iter().flat_map(|t| all_super_traits(db.upcast(), t));
@@ -655,6 +656,19 @@ fn iterate_trait_method_candidates(
655 'traits: for t in traits { 656 'traits: for t in traits {
656 let data = db.trait_data(t); 657 let data = db.trait_data(t);
657 658
659 // Traits annotated with `#[rustc_skip_array_during_method_dispatch]` are skipped during
660 // method resolution, if the receiver is an array, and we're compiling for editions before
661 // 2021.
662 // This is to make `[a].into_iter()` not break code with the new `IntoIterator` impl for
663 // arrays.
664 if data.skip_array_during_method_dispatch && receiver_is_array {
665 // FIXME: this should really be using the edition of the method name's span, in case it
666 // comes from a macro
667 if db.crate_graph()[krate].edition < Edition::Edition2021 {
668 continue;
669 }
670 }
671
658 // we'll be lazy about checking whether the type implements the 672 // we'll be lazy about checking whether the type implements the
659 // trait, but if we find out it doesn't, we'll skip the rest of the 673 // trait, but if we find out it doesn't, we'll skip the rest of the
660 // iteration 674 // iteration
diff --git a/crates/hir_ty/src/tests/method_resolution.rs b/crates/hir_ty/src/tests/method_resolution.rs
index 058eb9129..f26b2c8a7 100644
--- a/crates/hir_ty/src/tests/method_resolution.rs
+++ b/crates/hir_ty/src/tests/method_resolution.rs
@@ -1349,3 +1349,52 @@ fn f() {
1349 "#, 1349 "#,
1350 ); 1350 );
1351} 1351}
1352
1353#[test]
1354fn skip_array_during_method_dispatch() {
1355 check_types(
1356 r#"
1357//- /main2018.rs crate:main2018 deps:core
1358use core::IntoIterator;
1359
1360fn f() {
1361 let v = [4].into_iter();
1362 v;
1363 //^ &i32
1364
1365 let a = [0, 1].into_iter();
1366 a;
1367 //^ &i32
1368}
1369
1370//- /main2021.rs crate:main2021 deps:core edition:2021
1371use core::IntoIterator;
1372
1373fn f() {
1374 let v = [4].into_iter();
1375 v;
1376 //^ i32
1377
1378 let a = [0, 1].into_iter();
1379 a;
1380 //^ &i32
1381}
1382
1383//- /core.rs crate:core
1384#[rustc_skip_array_during_method_dispatch]
1385pub trait IntoIterator {
1386 type Out;
1387 fn into_iter(self) -> Self::Out;
1388}
1389
1390impl<T> IntoIterator for [T; 1] {
1391 type Out = T;
1392 fn into_iter(self) -> Self::Out {}
1393}
1394impl<'a, T> IntoIterator for &'a [T] {
1395 type Out = &'a T;
1396 fn into_iter(self) -> Self::Out {}
1397}
1398 "#,
1399 );
1400}