fill in todo

fmt

Author: asukaminato0721

crates/hir-ty/src/display.rs

@@ -68,6 +68,36 @@ use crate::{
     utils::{detect_variant_from_bytes, fn_traits},
 };
 
+fn async_gen_item_ty_from_yield_ty<'db>(
+    lang_items: &LangItems,
+    yield_ty: Ty<'db>,
+) -> Option<Ty<'db>> {
+    let poll_id = lang_items.Poll.map(hir_def::AdtId::EnumId)?;
+    let option_id = lang_items.Option.map(hir_def::AdtId::EnumId)?;
+
+    let TyKind::Adt(poll_def, poll_args) = yield_ty.kind() else {
+        return None;
+    };
+    if poll_def.inner().id != poll_id {
+        return None;
+    }
+    let [poll_inner] = poll_args.as_slice() else {
+        return None;
+    };
+    let poll_inner = poll_inner.ty()?;
+
+    let TyKind::Adt(option_def, option_args) = poll_inner.kind() else {
+        return None;
+    };
+    if option_def.inner().id != option_id {
+        return None;
+    }
+    let [item] = option_args.as_slice() else {
+        return None;
+    };
+    item.ty()
+}
+
 pub type Result<T = (), E = HirDisplayError> = std::result::Result<T, E>;
 
 pub trait HirWrite: fmt::Write {
@@ -1787,7 +1817,9 @@ impl<'db> HirDisplay<'db> for Ty<'db> {
                             f.end_location_link();
                         }
                         write!(f, " = ")?;
-                        yield_ty.hir_fmt(f)?;
+                        let item_ty = async_gen_item_ty_from_yield_ty(f.lang_items(), yield_ty)
+                            .unwrap_or(yield_ty);
+                        item_ty.hir_fmt(f)?;
                         write!(f, ">")?;
                     }
                     hir_def::hir::Expr::Closure {

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

@@ -2115,10 +2115,10 @@ fn test(mut cx: Context<'_>) {
             138..174 'async ...     }': impl AsyncIterator<Item = i8>
             158..167 'yield 1i8': ()
             164..167 '1i8': i8
-            184..190 'result': {unknown}
+            184..190 'result': Poll<Option<i8>>
             193..201 'Pin::new': fn new<&'? mut impl AsyncIterator<Item = i8>>(&'? mut impl AsyncIterator<Item = i8>) -> Pin<&'? mut impl AsyncIterator<Item = i8>>
             193..217 'Pin::n...rator)': Pin<&'? mut impl AsyncIterator<Item = i8>>
-            193..236 'Pin::n...ut cx)': Poll<Option<<impl AsyncIterator<Item = i8> as AsyncIterator>::Item>>
+            193..236 'Pin::n...ut cx)': Poll<Option<i8>>
             202..216 '&mut generator': &'? mut impl AsyncIterator<Item = i8>
             207..216 'generator': impl AsyncIterator<Item = i8>
             228..235 '&mut cx': &'? mut Context<'?>