Inline a few trivial conversion functions

compiler/rustc_infer/src/infer/type_variable.rs

@@ -416,6 +416,7 @@ impl<'tcx> ut::UnifyKey for TyVidEqKey<'tcx> {
     fn index(&self) -> u32 {
         self.vid.as_u32()
     }
+    #[inline]
     fn from_index(i: u32) -> Self {
         TyVidEqKey::from(ty::TyVid::from_u32(i))
     }

compiler/rustc_middle/src/infer/unify_key.rs

@@ -32,9 +32,11 @@ impl<'tcx> From<ty::RegionVid> for RegionVidKey<'tcx> {
 
 impl<'tcx> UnifyKey for RegionVidKey<'tcx> {
     type Value = UnifiedRegion<'tcx>;
+    #[inline]
     fn index(&self) -> u32 {
         self.vid.as_u32()
     }
+    #[inline]
     fn from_index(i: u32) -> Self {
         RegionVidKey::from(ty::RegionVid::from_u32(i))
     }
@@ -118,9 +120,11 @@ pub struct ConstVarValue<'tcx> {
 
 impl<'tcx> UnifyKey for ty::ConstVid<'tcx> {
     type Value = ConstVarValue<'tcx>;
+    #[inline]
     fn index(&self) -> u32 {
         self.index
     }
+    #[inline]
     fn from_index(i: u32) -> Self {
         ty::ConstVid { index: i, phantom: PhantomData }
     }

compiler/rustc_middle/src/ty/subst.rs

@@ -48,6 +48,7 @@ pub enum GenericArgKind<'tcx> {
 }
 
 impl<'tcx> GenericArgKind<'tcx> {
+    #[inline]
     fn pack(self) -> GenericArg<'tcx> {
         let (tag, ptr) = match self {
             GenericArgKind::Lifetime(lt) => {
@@ -94,18 +95,21 @@ impl<'tcx> PartialOrd for GenericArg<'tcx> {
 }
 
 impl<'tcx> From<ty::Region<'tcx>> for GenericArg<'tcx> {
+    #[inline]
     fn from(r: ty::Region<'tcx>) -> GenericArg<'tcx> {
         GenericArgKind::Lifetime(r).pack()
     }
 }
 
 impl<'tcx> From<Ty<'tcx>> for GenericArg<'tcx> {
+    #[inline]
     fn from(ty: Ty<'tcx>) -> GenericArg<'tcx> {
         GenericArgKind::Type(ty).pack()
     }
 }
 
 impl<'tcx> From<ty::Const<'tcx>> for GenericArg<'tcx> {
+    #[inline]
     fn from(c: ty::Const<'tcx>) -> GenericArg<'tcx> {
         GenericArgKind::Const(c).pack()
     }

compiler/rustc_mir_transform/src/dest_prop.rs

@@ -222,9 +222,11 @@ impl From<Local> for UnifyLocal {
 
 impl UnifyKey for UnifyLocal {
     type Value = ();
+    #[inline]
     fn index(&self) -> u32 {
         self.0.as_u32()
     }
+    #[inline]
     fn from_index(u: u32) -> Self {
         Self(Local::from_u32(u))
     }

compiler/rustc_span/src/hygiene.rs

@@ -172,10 +172,12 @@ impl LocalExpnId {
     /// The ID of the theoretical expansion that generates freshly parsed, unexpanded AST.
     pub const ROOT: LocalExpnId = LocalExpnId::from_u32(0);
 
+    #[inline]
     pub fn from_raw(idx: ExpnIndex) -> LocalExpnId {
         LocalExpnId::from_u32(idx.as_u32())
     }
 
+    #[inline]
     pub fn as_raw(self) -> ExpnIndex {
         ExpnIndex::from_u32(self.as_u32())
     }

compiler/rustc_target/src/spec/mod.rs

@@ -1541,11 +1541,13 @@ impl Default for TargetOptions {
 impl Deref for Target {
     type Target = TargetOptions;
 
+    #[inline]
     fn deref(&self) -> &Self::Target {
         &self.options
     }
 }
 impl DerefMut for Target {
+    #[inline]
     fn deref_mut(&mut self) -> &mut Self::Target {
         &mut self.options
     }

compiler/rustc_type_ir/src/lib.rs

@@ -400,9 +400,11 @@ pub enum InferTy {
 /// they carry no values.
 impl UnifyKey for TyVid {
     type Value = ();
+    #[inline]
     fn index(&self) -> u32 {
         self.as_u32()
     }
+    #[inline]
     fn from_index(i: u32) -> TyVid {
         TyVid::from_u32(i)
     }
@@ -419,6 +421,7 @@ impl UnifyKey for IntVid {
     fn index(&self) -> u32 {
         self.index
     }
+    #[inline]
     fn from_index(i: u32) -> IntVid {
         IntVid { index: i }
     }
@@ -431,9 +434,11 @@ impl EqUnifyValue for FloatVarValue {}
 
 impl UnifyKey for FloatVid {
     type Value = Option<FloatVarValue>;
+    #[inline]
     fn index(&self) -> u32 {
         self.index
     }
+    #[inline]
     fn from_index(i: u32) -> FloatVid {
         FloatVid { index: i }
     }