Support Pointee trait

Author: HKalbasi

Cargo.lock

@@ -22,10 +22,10 @@ either = "1.7.0"
 tracing = "0.1.35"
 rustc-hash = "1.1.0"
 scoped-tls = "1.0.0"
-chalk-solve = { version = "0.89.0", default-features = false }
-chalk-ir = "0.89.0"
-chalk-recursive = { version = "0.89.0", default-features = false }
-chalk-derive = "0.89.0"
+chalk-solve = { version = "0.91.0", default-features = false }
+chalk-ir = "0.91.0"
+chalk-recursive = { version = "0.91.0", default-features = false }
+chalk-derive = "0.91.0"
 la-arena = { version = "0.3.0", path = "../../lib/la-arena" }
 once_cell = "1.17.0"
 typed-arena = "2.0.1"

crates/hir-ty/Cargo.toml

@@ -584,6 +584,7 @@ fn well_known_trait_from_lang_item(item: LangItem) -> Option<WellKnownTrait> {
         LangItem::Unpin => WellKnownTrait::Unpin,
         LangItem::Unsize => WellKnownTrait::Unsize,
         LangItem::Tuple => WellKnownTrait::Tuple,
+        LangItem::PointeeTrait => WellKnownTrait::Pointee,
         _ => return None,
     })
 }
@@ -604,6 +605,7 @@ fn lang_item_from_well_known_trait(trait_: WellKnownTrait) -> LangItem {
         WellKnownTrait::Tuple => LangItem::Tuple,
         WellKnownTrait::Unpin => LangItem::Unpin,
         WellKnownTrait::Unsize => LangItem::Unsize,
+        WellKnownTrait::Pointee => LangItem::PointeeTrait,
     }
 }
 

crates/hir-ty/src/chalk_db.rs

@@ -3400,6 +3400,22 @@ fn func() {
     );
 }
 
+#[test]
+fn pointee_trait() {
+    check_types(
+        r#"
+//- minicore: pointee
+use core::ptr::Pointee;
+fn func() {
+    let x: <u8 as Pointee>::Metadata;
+      //^ ()
+    let x: <[u8] as Pointee>::Metadata;
+      //^ usize
+}
+    "#,
+    );
+}
+
 // FIXME
 #[test]
 fn castable_to() {

crates/hir-ty/src/tests/simple.rs

@@ -387,6 +387,10 @@ impl MiniCore {
             }
         }
 
+        if !active_regions.is_empty() {
+            panic!("unclosed regions: {:?} Add an `endregion` comment", active_regions);
+        }
+
         for flag in &self.valid_flags {
             if !seen_regions.iter().any(|it| it == flag) {
                 panic!("unused minicore flag: {flag:?}");

crates/test-utils/src/fixture.rs

@@ -37,6 +37,7 @@
 //!     ord: eq, option
 //!     panic:
 //!     pin:
+//!     pointee:
 //!     range:
 //!     result:
 //!     send: sized
@@ -752,6 +753,16 @@ pub mod result {
 }
 // endregion:result
 
+// region:pointee
+pub mod ptr {
+    #[lang = "pointee_trait"]
+    pub trait Pointee {
+        #[lang = "metadata_type"]
+        type Metadata;
+    }
+}
+// endregion:pointee
+
 // region:pin
 pub mod pin {
     #[lang = "pin"]