rust-analyzer

diff --git a/crates/hir_ty/src/diagnostics/expr.rs b/crates/hir_ty/src/diagnostics/expr.rs
index 00c7b95215..a8c4026e31 100644
--- a/crates/hir_ty/src/diagnostics/expr.rs
+++ b/crates/hir_ty/src/diagnostics/expr.rs

@@ -285,6 +285,7 @@ impl ExprValidator {

let pattern_arena = Arena::new();

let cx = MatchCheckCtx {

module: self.owner.module(db.upcast()),

+ body: self.owner,

db,

pattern_arena: &pattern_arena,

};

diff --git a/crates/hir_ty/src/diagnostics/match_check/deconstruct_pat.rs b/crates/hir_ty/src/diagnostics/match_check/deconstruct_pat.rs
index acb3280329..84ded517ba 100644
--- a/crates/hir_ty/src/diagnostics/match_check/deconstruct_pat.rs
+++ b/crates/hir_ty/src/diagnostics/match_check/deconstruct_pat.rs

@@ -53,7 +53,7 @@ use smallvec::{smallvec, SmallVec};

use stdx::never;

use syntax::SmolStr;

-use crate::{AdtId, Interner, Scalar, Ty, TyExt, TyKind};

+use crate::{infer::normalize, AdtId, Interner, Scalar, Ty, TyExt, TyKind};

use super::{

usefulness::{helper::Captures, MatchCheckCtx, PatCtxt},

@@ -753,8 +753,8 @@ impl<'p> Fields<'p> {

let fields_len = variant.variant_data(cx.db.upcast()).fields().len() as u32;

(0..fields_len).map(|idx| LocalFieldId::from_raw(idx.into())).filter_map(move |fid| {

- // TODO check ty has been normalized

let ty = field_ty[fid].clone().substitute(Interner, substs);

+ let ty = normalize(cx.db, cx.body, ty);

let is_visible = matches!(adt, hir_def::AdtId::EnumId(..))

|| visibility[fid].is_visible_from(cx.db.upcast(), cx.module);

let is_uninhabited = cx.is_uninhabited(&ty);

diff --git a/crates/hir_ty/src/diagnostics/match_check/usefulness.rs b/crates/hir_ty/src/diagnostics/match_check/usefulness.rs
index 9b00c4dccf..e8a13955d2 100644
--- a/crates/hir_ty/src/diagnostics/match_check/usefulness.rs
+++ b/crates/hir_ty/src/diagnostics/match_check/usefulness.rs

@@ -273,7 +273,7 @@

use std::iter::once;

-use hir_def::{AdtId, HasModule, ModuleId};

+use hir_def::{AdtId, DefWithBodyId, HasModule, ModuleId};

use smallvec::{smallvec, SmallVec};

use typed_arena::Arena;

@@ -285,6 +285,7 @@ use self::{helper::Captures, ArmType::*, Usefulness::*};

pub(crate) struct MatchCheckCtx<'a, 'p> {

pub(crate) module: ModuleId,

+ pub(crate) body: DefWithBodyId,

pub(crate) db: &'a dyn HirDatabase,

/// Lowered patterns from arms plus generated by the check.

pub(crate) pattern_arena: &'p Arena<DeconstructedPat<'p>>,

diff --git a/crates/hir_ty/src/infer.rs b/crates/hir_ty/src/infer.rs
index 1bc19323da..95d9a6735a 100644
--- a/crates/hir_ty/src/infer.rs
+++ b/crates/hir_ty/src/infer.rs

@@ -16,7 +16,7 @@

use std::ops::Index;

use std::sync::Arc;

-use chalk_ir::{cast::Cast, DebruijnIndex, Mutability, Safety, Scalar};

+use chalk_ir::{cast::Cast, DebruijnIndex, Mutability, Safety, Scalar, TypeFlags};

use hir_def::{

body::Body,

data::{ConstData, FunctionData, StaticData},

@@ -70,6 +70,26 @@ pub(crate) fn infer_query(db: &dyn HirDatabase, def: DefWithBodyId) -> Arc<Infer

Arc::new(ctx.resolve_all())

}

+/// Fully normalize all the types found within `ty` in context of `owner` body definition.

+///

+/// This is appropriate to use only after type-check: it assumes

+/// that normalization will succeed, for example.

+pub(crate) fn normalize(db: &dyn HirDatabase, owner: DefWithBodyId, ty: Ty) -> Ty {

+ if !ty.data(Interner).flags.intersects(TypeFlags::HAS_PROJECTION) {

+ return ty;

+ }

+ let krate = owner.module(db.upcast()).krate();

+ let trait_env = owner

+ .as_generic_def_id()

+ .map_or_else(|| Arc::new(TraitEnvironment::empty(krate)), |d| db.trait_environment(d));

+ let mut table = unify::InferenceTable::new(db, trait_env.clone());

+ let ty_with_vars = table.normalize_associated_types_in(ty);

+ table.resolve_obligations_as_possible();

+ table.propagate_diverging_flag();

+ table.resolve_completely(ty_with_vars)

#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]

enum ExprOrPatId {

ExprId(ExprId),

diff --git a/crates/ide_diagnostics/src/handlers/missing_match_arms.rs b/crates/ide_diagnostics/src/handlers/missing_match_arms.rs
index 5a35704697..5ef4d2a226 100644
--- a/crates/ide_diagnostics/src/handlers/missing_match_arms.rs
+++ b/crates/ide_diagnostics/src/handlers/missing_match_arms.rs

@@ -863,6 +863,30 @@ fn main() {

);

}

+ #[test]

+ fn normalize_field_ty() {

+ check_diagnostics_no_bails(

+ r"

+trait Trait { type Projection; }

+enum E {Foo, Bar}

+struct A;

+impl Trait for A { type Projection = E; }

+struct Next<T: Trait>(T::Projection);

+static __: () = {

+ let n: Next<A> = Next(E::Foo);

+ match n { Next(E::Foo) => {} }

+ // ^ error: missing match arm

+ match n { Next(E::Foo | E::Bar) => {} }

+ match n { Next(E::Foo | _ ) => {} }

+ match n { Next(_ | E::Bar) => {} }

+ match n { _ | Next(E::Bar) => {} }

+ match &n { Next(E::Foo | E::Bar) => {} }

+ match &n { _ | Next(E::Bar) => {} }

+};",

+ );

+ }

mod false_negatives {

//! The implementation of match checking here is a work in progress. As we roll this out, we

//! prefer false negatives to false positives (ideally there would be no false positives). This