implement type_name intrinsic

Author: HKalbasi

crates/base-db/src/fixture.rs

@@ -26,7 +26,7 @@ pub trait WithFixture: Default + SourceDatabaseExt + 'static {
         let fixture = ChangeFixture::parse(ra_fixture);
         let mut db = Self::default();
         fixture.change.apply(&mut db);
-        assert_eq!(fixture.files.len(), 1);
+        assert_eq!(fixture.files.len(), 1, "Multiple file found in the fixture");
         (db, fixture.files[0])
     }
 

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

@@ -4,7 +4,7 @@ use hir_def::db::DefDatabase;
 
 use crate::{
     consteval::try_const_usize, db::HirDatabase, mir::pad16, test_db::TestDB, Const, ConstScalar,
-    Interner,
+    Interner, MemoryMap,
 };
 
 use super::{
@@ -36,7 +36,7 @@ fn check_fail(ra_fixture: &str, error: impl FnOnce(ConstEvalError) -> bool) {
 
 #[track_caller]
 fn check_number(ra_fixture: &str, answer: i128) {
-    check_answer(ra_fixture, |b| {
+    check_answer(ra_fixture, |b, _| {
         assert_eq!(
             b,
             &answer.to_le_bytes()[0..b.len()],
@@ -47,8 +47,26 @@ fn check_number(ra_fixture: &str, answer: i128) {
 }
 
 #[track_caller]
-fn check_answer(ra_fixture: &str, check: impl FnOnce(&[u8])) {
-    let (db, file_id) = TestDB::with_single_file(ra_fixture);
+fn check_str(ra_fixture: &str, answer: &str) {
+    check_answer(ra_fixture, |b, mm| {
+        let addr = usize::from_le_bytes(b[0..b.len() / 2].try_into().unwrap());
+        let size = usize::from_le_bytes(b[b.len() / 2..].try_into().unwrap());
+        let Some(bytes) = mm.get(addr, size) else {
+            panic!("string data missed in the memory map");
+        };
+        assert_eq!(
+            bytes,
+            answer.as_bytes(),
+            "Bytes differ. In string form: actual = {}, expected = {answer}",
+            String::from_utf8_lossy(bytes)
+        );
+    });
+}
+
+#[track_caller]
+fn check_answer(ra_fixture: &str, check: impl FnOnce(&[u8], &MemoryMap)) {
+    let (db, file_ids) = TestDB::with_many_files(ra_fixture);
+    let file_id = *file_ids.last().unwrap();
     let r = match eval_goal(&db, file_id) {
         Ok(t) => t,
         Err(e) => {
@@ -58,8 +76,8 @@ fn check_answer(ra_fixture: &str, check: impl FnOnce(&[u8])) {
     };
     match &r.data(Interner).value {
         chalk_ir::ConstValue::Concrete(c) => match &c.interned {
-            ConstScalar::Bytes(b, _) => {
-                check(b);
+            ConstScalar::Bytes(b, mm) => {
+                check(b, mm);
             }
             x => panic!("Expected number but found {:?}", x),
         },
@@ -224,7 +242,7 @@ const GOAL: usize = {
     transmute(&x)
 }
         "#,
-        |b| assert_eq!(b[0] % 8, 0),
+        |b, _| assert_eq!(b[0] % 8, 0),
     );
     check_answer(
         r#"
@@ -233,7 +251,7 @@ use core::mem::transmute;
 static X: i64 = 12;
 const GOAL: usize = transmute(&X);
         "#,
-        |b| assert_eq!(b[0] % 8, 0),
+        |b, _| assert_eq!(b[0] % 8, 0),
     );
 }
 
@@ -2067,6 +2085,17 @@ fn array_and_index() {
     );
 }
 
+#[test]
+fn string() {
+    check_str(
+        r#"
+    //- minicore: coerce_unsized, index, slice
+    const GOAL: &str = "hello";
+        "#,
+        "hello",
+    );
+}
+
 #[test]
 fn byte_string() {
     check_number(
@@ -2443,6 +2472,25 @@ fn const_trait_assoc() {
     "#,
         32,
     );
+    check_number(
+        r#"
+    //- /a/lib.rs crate:a
+    pub trait ToConst {
+        const VAL: usize;
+    }
+    pub const fn to_const<T: ToConst>() -> usize {
+        T::VAL
+    }
+    //- /main.rs crate:main deps:a
+    use a::{ToConst, to_const};
+    struct U0;
+    impl ToConst for U0 {
+        const VAL: usize = 5;
+    }
+    const GOAL: usize = to_const::<U0>();
+    "#,
+        5,
+    );
     check_number(
         r#"
     struct S<T>(*mut T);

crates/hir-ty/src/consteval/tests/intrinsics.rs

@@ -149,6 +149,36 @@ fn min_align_of_val() {
     );
 }
 
+#[test]
+fn type_name() {
+    check_str(
+        r#"
+        extern "rust-intrinsic" {
+            pub fn type_name<T: ?Sized>() -> &'static str;
+        }
+
+        const GOAL: &str = type_name::<i32>();
+        "#,
+        "i32",
+    );
+    check_str(
+        r#"
+        extern "rust-intrinsic" {
+            pub fn type_name<T: ?Sized>() -> &'static str;
+        }
+
+        mod mod1 {
+            pub mod mod2 {
+                pub struct Ty;
+            }
+        }
+
+        const GOAL: &str = type_name::<mod1::mod2::Ty>();
+        "#,
+        "mod1::mod2::Ty",
+    );
+}
+
 #[test]
 fn transmute() {
     check_number(

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

@@ -29,7 +29,7 @@ use crate::{
     infer::PointerCast,
     layout::{Layout, LayoutError, RustcEnumVariantIdx},
     mapping::from_chalk,
-    method_resolution::is_dyn_method,
+    method_resolution::{is_dyn_method, lookup_impl_const},
     name, static_lifetime,
     traits::FnTrait,
     utils::{detect_variant_from_bytes, ClosureSubst},
@@ -1571,35 +1571,51 @@ impl Evaluator<'_> {
         let chalk_ir::ConstValue::Concrete(c) = &konst.data(Interner).value else {
             not_supported!("evaluating non concrete constant");
         };
-        Ok(match &c.interned {
-            ConstScalar::Bytes(v, memory_map) => {
-                let mut v: Cow<'_, [u8]> = Cow::Borrowed(v);
-                let patch_map = memory_map.transform_addresses(|b, align| {
-                    let addr = self.heap_allocate(b.len(), align)?;
-                    self.write_memory(addr, b)?;
-                    Ok(addr.to_usize())
+        let result_owner;
+        let (v, memory_map) = match &c.interned {
+            ConstScalar::Bytes(v, mm) => (v, mm),
+            ConstScalar::UnevaluatedConst(const_id, subst) => 'b: {
+                let mut const_id = *const_id;
+                let mut subst = subst.clone();
+                if let hir_def::GeneralConstId::ConstId(c) = const_id {
+                    let (c, s) = lookup_impl_const(self.db, self.trait_env.clone(), c, subst);
+                    const_id = hir_def::GeneralConstId::ConstId(c);
+                    subst = s;
+                }
+                result_owner = self.db.const_eval(const_id.into(), subst).map_err(|e| {
+                    let name = const_id.name(self.db.upcast());
+                    MirEvalError::ConstEvalError(name, Box::new(e))
                 })?;
-                let (size, align) = self.size_align_of(ty, locals)?.unwrap_or((v.len(), 1));
-                if size != v.len() {
-                    // Handle self enum
-                    if size == 16 && v.len() < 16 {
-                        v = Cow::Owned(pad16(&v, false).to_vec());
-                    } else if size < 16 && v.len() == 16 {
-                        v = Cow::Owned(v[0..size].to_vec());
-                    } else {
-                        return Err(MirEvalError::InvalidConst(konst.clone()));
+                if let chalk_ir::ConstValue::Concrete(c) = &result_owner.data(Interner).value {
+                    if let ConstScalar::Bytes(v, mm) = &c.interned {
+                        break 'b (v, mm);
                     }
                 }
-                let addr = self.heap_allocate(size, align)?;
-                self.write_memory(addr, &v)?;
-                self.patch_addresses(&patch_map, &memory_map.vtable, addr, ty, locals)?;
-                Interval::new(addr, size)
-            }
-            ConstScalar::UnevaluatedConst(..) => {
-                not_supported!("unevaluated const present in monomorphized mir");
+                not_supported!("unevaluatable constant");
             }
             ConstScalar::Unknown => not_supported!("evaluating unknown const"),
-        })
+        };
+        let mut v: Cow<'_, [u8]> = Cow::Borrowed(v);
+        let patch_map = memory_map.transform_addresses(|b, align| {
+            let addr = self.heap_allocate(b.len(), align)?;
+            self.write_memory(addr, b)?;
+            Ok(addr.to_usize())
+        })?;
+        let (size, align) = self.size_align_of(ty, locals)?.unwrap_or((v.len(), 1));
+        if size != v.len() {
+            // Handle self enum
+            if size == 16 && v.len() < 16 {
+                v = Cow::Owned(pad16(&v, false).to_vec());
+            } else if size < 16 && v.len() == 16 {
+                v = Cow::Owned(v[0..size].to_vec());
+            } else {
+                return Err(MirEvalError::InvalidConst(konst.clone()));
+            }
+        }
+        let addr = self.heap_allocate(size, align)?;
+        self.write_memory(addr, &v)?;
+        self.patch_addresses(&patch_map, &memory_map.vtable, addr, ty, locals)?;
+        Ok(Interval::new(addr, size))
     }
 
     fn eval_place(&mut self, p: &Place, locals: &Locals) -> Result<Interval> {

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

@@ -602,6 +602,26 @@ impl Evaluator<'_> {
                     destination.write_from_bytes(self, &align.to_le_bytes())
                 }
             }
+            "type_name" => {
+                let Some(ty) = generic_args.as_slice(Interner).get(0).and_then(|it| it.ty(Interner))
+                else {
+                    return Err(MirEvalError::TypeError("type_name generic arg is not provided"));
+                };
+                let Ok(ty_name) = ty.display_source_code(
+                    self.db,
+                    locals.body.owner.module(self.db.upcast()),
+                    true,
+                ) else {
+                    not_supported!("fail in generating type_name using source code display");
+                };
+                let len = ty_name.len();
+                let addr = self.heap_allocate(len, 1)?;
+                self.write_memory(addr, ty_name.as_bytes())?;
+                destination.slice(0..self.ptr_size()).write_from_bytes(self, &addr.to_bytes())?;
+                destination
+                    .slice(self.ptr_size()..2 * self.ptr_size())
+                    .write_from_bytes(self, &len.to_le_bytes())
+            }
             "needs_drop" => {
                 let Some(ty) = generic_args.as_slice(Interner).get(0).and_then(|it| it.ty(Interner))
                 else {

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

@@ -13,15 +13,14 @@ use chalk_ir::{
     fold::{FallibleTypeFolder, TypeFoldable, TypeSuperFoldable},
     ConstData, DebruijnIndex,
 };
-use hir_def::{DefWithBodyId, GeneralConstId};
+use hir_def::DefWithBodyId;
 use triomphe::Arc;
 
 use crate::{
-    consteval::unknown_const,
+    consteval::{intern_const_scalar, unknown_const},
     db::HirDatabase,
     from_placeholder_idx,
     infer::normalize,
-    method_resolution::lookup_impl_const,
     utils::{generics, Generics},
     ClosureId, Const, Interner, ProjectionTy, Substitution, TraitEnvironment, Ty, TyKind,
 };
@@ -193,25 +192,12 @@ impl Filler<'_> {
                     | chalk_ir::ConstValue::Placeholder(_) => {}
                     chalk_ir::ConstValue::Concrete(cc) => match &cc.interned {
                         crate::ConstScalar::UnevaluatedConst(const_id, subst) => {
-                            let mut const_id = *const_id;
                             let mut subst = subst.clone();
                             self.fill_subst(&mut subst)?;
-                            if let GeneralConstId::ConstId(c) = const_id {
-                                let (c, s) = lookup_impl_const(
-                                    self.db,
-                                    self.db.trait_environment_for_body(self.owner),
-                                    c,
-                                    subst,
-                                );
-                                const_id = GeneralConstId::ConstId(c);
-                                subst = s;
-                            }
-                            let result =
-                                self.db.const_eval(const_id.into(), subst).map_err(|e| {
-                                    let name = const_id.name(self.db.upcast());
-                                    MirLowerError::ConstEvalError(name, Box::new(e))
-                                })?;
-                            *c = result;
+                            *c = intern_const_scalar(
+                                crate::ConstScalar::UnevaluatedConst(*const_id, subst),
+                                c.data(Interner).ty.clone(),
+                            );
                         }
                         crate::ConstScalar::Bytes(_, _) | crate::ConstScalar::Unknown => (),
                     },

crates/ide/src/interpret_function.rs

@@ -34,13 +34,15 @@ fn find_and_interpret(db: &RootDatabase, position: FilePosition) -> Option<Strin
         _ => return None,
     };
     let span_formatter = |file_id, text_range: TextRange| {
-        let line_col = db.line_index(file_id).line_col(text_range.start());
         let path = &db
             .source_root(db.file_source_root(file_id))
             .path_for_file(&file_id)
             .map(|x| x.to_string());
         let path = path.as_deref().unwrap_or("<unknown file>");
-        format!("file://{path}#{}:{}", line_col.line + 1, line_col.col)
+        match db.line_index(file_id).try_line_col(text_range.start()) {
+            Some(line_col) => format!("file://{path}#{}:{}", line_col.line + 1, line_col.col),
+            None => format!("file://{path} range {:?}", text_range),
+        }
     };
     Some(def.eval(db, span_formatter))
 }