Remove query_helper_param_ty.

The query key sloppiness mentioned in the previous commit has another
component: `query_helper_param_ty` only uses `IntoQueryParam` when the
key type is `DefId` or `LocalDefId`.

But thanks to the previous commit, `DefId` and `LocalDefId` are the only
`T`s for which `IntoQueryParam<T>` is implemented. So we can just get
rid of `query_helper_param_ty` and always use `IntoQueryParam` for every
type. The net effect is the same, and makes the code simpler.

Furthermore, `query_helper_param_ty`'s special cases required that the
key in the macro be `$($K:tt)*` for the literal `DefId`/`LocalDefId`
matches to work. With those gone, the next commit will change the key to
the simpler `$K:ty`.

Author: nnethercote

compiler/rustc_middle/src/mir/mono.rs

@@ -277,7 +277,7 @@ impl<'tcx> MonoItem<'tcx> {
             MonoItem::GlobalAsm(..) => return true,
         };
 
-        !tcx.instantiate_and_check_impossible_predicates((def_id, &args))
+        !tcx.instantiate_and_check_impossible_predicates((def_id, args))
     }
 
     pub fn local_span(&self, tcx: TyCtxt<'tcx>) -> Option<Span> {

compiler/rustc_middle/src/query/plumbing.rs

@@ -262,12 +262,6 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 }
 
-macro_rules! query_helper_param_ty {
-    (DefId) => { impl $crate::query::IntoQueryParam<DefId> };
-    (LocalDefId) => { impl $crate::query::IntoQueryParam<LocalDefId> };
-    ($K:ty) => { $K };
-}
-
 // Expands to `$then` if the `arena_cache` modifier is present, `$else` otherwise.
 macro_rules! if_arena_cache {
     ([] $_then:tt $else:tt) => { $else };
@@ -416,7 +410,7 @@ macro_rules! define_callbacks {
                 #[inline(always)]
                 pub fn $name(
                     self,
-                    key: query_helper_param_ty!($($K)*),
+                    key: impl $crate::query::IntoQueryParam<$($K)*>,
                 ) -> if_return_result_from_ensure_ok!(
                     [$($modifiers)*]
                     (Result<(), ErrorGuaranteed>)
@@ -447,7 +441,7 @@ macro_rules! define_callbacks {
             $(
                 $(#[$attr])*
                 #[inline(always)]
-                pub fn $name(self, key: query_helper_param_ty!($($K)*)) {
+                pub fn $name(self, key: impl $crate::query::IntoQueryParam<$($K)*>) {
                     crate::query::inner::query_ensure(
                         self.tcx,
                         self.tcx.query_system.fns.engine.$name,
@@ -464,7 +458,7 @@ macro_rules! define_callbacks {
                 $(#[$attr])*
                 #[inline(always)]
                 #[must_use]
-                pub fn $name(self, key: query_helper_param_ty!($($K)*)) -> $V {
+                pub fn $name(self, key: impl $crate::query::IntoQueryParam<$($K)*>) -> $V {
                     self.at(DUMMY_SP).$name(key)
                 }
             )*
@@ -474,7 +468,7 @@ macro_rules! define_callbacks {
             $(
                 $(#[$attr])*
                 #[inline(always)]
-                pub fn $name(self, key: query_helper_param_ty!($($K)*)) -> $V {
+                pub fn $name(self, key: impl $crate::query::IntoQueryParam<$($K)*>) -> $V {
                     use $crate::query::{erase, inner};
 
                     erase::restore_val::<$V>(inner::query_get_at(