Remove astconv usage in diagnostic

compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs

@@ -1336,16 +1336,17 @@ pub(crate) fn suggest_associated_const(
                 hir::Path { segments: [segment], .. },
             ))
             | hir::ExprKind::Path(QPath::TypeRelative(ty, segment)) => {
-                let self_ty = self.astconv().ast_ty_to_ty(ty);
-                if let Ok(pick) = self.probe_for_name(
-                    Mode::Path,
-                    Ident::new(capitalized_name, segment.ident.span),
-                    Some(expected_ty),
-                    IsSuggestion(true),
-                    self_ty,
-                    expr.hir_id,
-                    ProbeScope::TraitsInScope,
-                ) {
+                if let Some(self_ty) = self.typeck_results.borrow().node_type_opt(ty.hir_id)
+                    && let Ok(pick) = self.probe_for_name(
+                        Mode::Path,
+                        Ident::new(capitalized_name, segment.ident.span),
+                        Some(expected_ty),
+                        IsSuggestion(true),
+                        self_ty,
+                        expr.hir_id,
+                        ProbeScope::TraitsInScope,
+                    )
+                {
                     (pick.item, segment)
                 } else {
                     return false;

tests/ui/typeck/issue-107775.rs

@@ -0,0 +1,40 @@
+// edition: 2021
+
+use std::collections::HashMap;
+use std::future::Future;
+use std::pin::Pin;
+
+pub trait Trait {
+    fn do_something<'async_trait>(byte: u8)
+    ->
+        Pin<Box<dyn Future<Output = ()> +
+        Send + 'async_trait>>;
+}
+
+pub struct Struct;
+
+impl Trait for Struct {
+    fn do_something<'async_trait>(byte: u8)
+        ->
+            Pin<Box<dyn Future<Output = ()> +
+            Send + 'async_trait>> {
+        Box::pin(
+
+            async move { let byte = byte; let _: () = {}; })
+    }
+}
+
+pub struct Map {
+    map: HashMap<u16, fn(u8) -> Pin<Box<dyn Future<Output = ()> + Send>>>,
+}
+
+impl Map {
+    pub fn new() -> Self {
+        let mut map = HashMap::new();
+        map.insert(1, Struct::do_something);
+        Self { map }
+        //~^ ERROR mismatched types
+    }
+}
+
+fn main() {}

tests/ui/typeck/issue-107775.stderr

@@ -0,0 +1,16 @@
+error[E0308]: mismatched types
+  --> $DIR/issue-107775.rs:35:16
+   |
+LL |         map.insert(1, Struct::do_something);
+   |                    -  -------------------- this is of type `fn(u8) -> Pin<Box<dyn Future<Output = ()> + Send>> {<Struct as Trait>::do_something::<'_>}`, which causes `map` to be inferred as `HashMap<{integer}, fn(u8) -> Pin<Box<dyn Future<Output = ()> + Send>> {<Struct as Trait>::do_something::<'_>}>`
+   |                    |
+   |                    this is of type `{integer}`, which causes `map` to be inferred as `HashMap<{integer}, fn(u8) -> Pin<Box<dyn Future<Output = ()> + Send>> {<Struct as Trait>::do_something::<'_>}>`
+LL |         Self { map }
+   |                ^^^ expected `HashMap<u16, fn(u8) -> Pin<...>>`, found `HashMap<{integer}, ...>`
+   |
+   = note: expected struct `HashMap<u16, fn(_) -> Pin<Box<(dyn Future<Output = ()> + Send + 'static)>>>`
+              found struct `HashMap<{integer}, fn(_) -> Pin<Box<dyn Future<Output = ()> + Send>> {<Struct as Trait>::do_something::<'_>}>`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.