Merge pull request #21235 from benodiwal/fix-const-generic-param-env-panic

fix: resolve const generic param-env panic in type projection

Author: ChayimFriedman2

crates/hir-ty/src/infer/closure/analysis.rs

@@ -43,6 +43,7 @@ impl<'db> HirPlace<'db> {
         for p in &self.projections {
             ty = p.projected_ty(
                 &ctx.table.infer_ctxt,
+                ctx.table.param_env,
                 ty,
                 |_, _, _| {
                     unreachable!("Closure field only happens in MIR");
@@ -839,6 +840,7 @@ impl<'db> InferenceContext<'_, 'db> {
             for (i, p) in capture.place.projections.iter().enumerate() {
                 ty = p.projected_ty(
                     &self.table.infer_ctxt,
+                    self.table.param_env,
                     ty,
                     |_, _, _| {
                         unreachable!("Closure field only happens in MIR");

crates/hir-ty/src/layout.rs

@@ -25,7 +25,7 @@ use crate::{
     consteval::try_const_usize,
     db::HirDatabase,
     next_solver::{
-        DbInterner, GenericArgs, ParamEnv, Ty, TyKind, TypingMode,
+        DbInterner, GenericArgs, Ty, TyKind, TypingMode,
         infer::{DbInternerInferExt, traits::ObligationCause},
     },
 };
@@ -170,7 +170,7 @@ pub fn layout_of_ty_query<'db>(
     let cx = LayoutCx::new(dl);
     let infer_ctxt = interner.infer_ctxt().build(TypingMode::PostAnalysis);
     let cause = ObligationCause::dummy();
-    let ty = infer_ctxt.at(&cause, ParamEnv::empty()).deeply_normalize(ty).unwrap_or(ty);
+    let ty = infer_ctxt.at(&cause, trait_env.param_env).deeply_normalize(ty).unwrap_or(ty);
     let result = match ty.kind() {
         TyKind::Adt(def, args) => {
             match def.inner().id {

crates/hir-ty/src/mir.rs

@@ -157,6 +157,7 @@ impl<'db, V: PartialEq> ProjectionElem<'db, V> {
     pub fn projected_ty(
         &self,
         infcx: &InferCtxt<'db>,
+        env: ParamEnv<'db>,
         mut base: Ty<'db>,
         closure_field: impl FnOnce(InternedClosureId, GenericArgs<'db>, usize) -> Ty<'db>,
         krate: Crate,
@@ -173,8 +174,6 @@ impl<'db, V: PartialEq> ProjectionElem<'db, V> {
 
         if matches!(base.kind(), TyKind::Alias(..)) {
             let mut ocx = ObligationCtxt::new(infcx);
-            // FIXME: we should get this from caller
-            let env = ParamEnv::empty();
             match ocx.structurally_normalize_ty(&ObligationCause::dummy(), env, base) {
                 Ok(it) => base = it,
                 Err(_) => return Ty::new_error(interner, ErrorGuaranteed),

crates/hir-ty/src/mir/borrowck.rs

@@ -106,7 +106,7 @@ pub fn borrowck_query<'db>(
         // FIXME(next-solver): Opaques.
         let infcx = interner.infer_ctxt().build(typing_mode);
         res.push(BorrowckResult {
-            mutability_of_locals: mutability_of_locals(&infcx, &body),
+            mutability_of_locals: mutability_of_locals(&infcx, env, &body),
             moved_out_of_ref: moved_out_of_ref(&infcx, env, &body),
             partially_moved: partially_moved(&infcx, env, &body),
             borrow_regions: borrow_regions(db, &body),
@@ -146,6 +146,7 @@ fn moved_out_of_ref<'db>(
                 }
                 ty = proj.projected_ty(
                     infcx,
+                    env,
                     ty,
                     make_fetch_closure_field(db),
                     body.owner.module(db).krate(db),
@@ -242,6 +243,7 @@ fn partially_moved<'db>(
             for proj in p.projection.lookup(&body.projection_store) {
                 ty = proj.projected_ty(
                     infcx,
+                    env,
                     ty,
                     make_fetch_closure_field(db),
                     body.owner.module(db).krate(db),
@@ -374,6 +376,7 @@ enum ProjectionCase {
 
 fn place_case<'db>(
     infcx: &InferCtxt<'db>,
+    env: ParamEnv<'db>,
     body: &MirBody<'db>,
     lvalue: &Place<'db>,
 ) -> ProjectionCase {
@@ -395,6 +398,7 @@ fn place_case<'db>(
         }
         ty = proj.projected_ty(
             infcx,
+            env,
             ty,
             make_fetch_closure_field(db),
             body.owner.module(db).krate(db),
@@ -535,6 +539,7 @@ fn record_usage_for_operand<'db>(
 
 fn mutability_of_locals<'db>(
     infcx: &InferCtxt<'db>,
+    env: ParamEnv<'db>,
     body: &MirBody<'db>,
 ) -> ArenaMap<LocalId<'db>, MutabilityReason> {
     let db = infcx.interner.db;
@@ -547,7 +552,7 @@ fn mutability_of_locals<'db>(
         for statement in &block.statements {
             match &statement.kind {
                 StatementKind::Assign(place, value) => {
-                    match place_case(infcx, body, place) {
+                    match place_case(infcx, env, body, place) {
                         ProjectionCase::Direct => {
                             if ever_init_map.get(place.local).copied().unwrap_or_default() {
                                 push_mut_span(place.local, statement.span, &mut result);
@@ -596,7 +601,7 @@ fn mutability_of_locals<'db>(
                         },
                         p,
                     ) = value
-                        && place_case(infcx, body, p) != ProjectionCase::Indirect
+                        && place_case(infcx, env, body, p) != ProjectionCase::Indirect
                     {
                         push_mut_span(p.local, statement.span, &mut result);
                     }

crates/hir-ty/src/mir/eval.rs

@@ -722,6 +722,7 @@ impl<'db> Evaluator<'db> {
         let (ty, proj) = pair;
         let r = proj.projected_ty(
             &self.infcx,
+            self.param_env.param_env,
             ty,
             |c, subst, f| {
                 let InternedClosure(def, _) = self.db.lookup_intern_closure(c);

crates/hir-ty/src/mir/lower/tests.rs

@@ -1,3 +1,4 @@
+use hir_def::DefWithBodyId;
 use test_fixture::WithFixture;
 
 use crate::{db::HirDatabase, setup_tracing, test_db::TestDB};
@@ -49,3 +50,61 @@ fn foo() {
     "#,
     );
 }
+
+fn check_borrowck(#[rust_analyzer::rust_fixture] ra_fixture: &str) {
+    let _tracing = setup_tracing();
+    let (db, file_ids) = TestDB::with_many_files(ra_fixture);
+    crate::attach_db(&db, || {
+        let file_id = *file_ids.last().unwrap();
+        let module_id = db.module_for_file(file_id.file_id(&db));
+        let def_map = module_id.def_map(&db);
+        let scope = &def_map[module_id].scope;
+
+        let mut bodies: Vec<DefWithBodyId> = Vec::new();
+
+        for decl in scope.declarations() {
+            if let hir_def::ModuleDefId::FunctionId(f) = decl {
+                bodies.push(f.into());
+            }
+        }
+
+        for impl_id in scope.impls() {
+            let impl_items = impl_id.impl_items(&db);
+            for (_, item) in impl_items.items.iter() {
+                if let hir_def::AssocItemId::FunctionId(f) = item {
+                    bodies.push((*f).into());
+                }
+            }
+        }
+
+        for body in bodies {
+            let _ = db.borrowck(body);
+        }
+    })
+}
+
+#[test]
+fn regression_21173_const_generic_impl_with_assoc_type() {
+    check_borrowck(
+        r#"
+pub trait Tr {
+    type Assoc;
+    fn f(&self, handle: Self::Assoc) -> i32;
+}
+
+pub struct ConstGeneric<const N: usize>;
+
+impl<const N: usize> Tr for &ConstGeneric<N> {
+    type Assoc = AssocTy;
+
+    fn f(&self, a: Self::Assoc) -> i32 {
+        a.x
+    }
+}
+
+pub struct AssocTy {
+    x: i32,
+}
+    "#,
+    );
+}