Rename Ty::Param => Ty::Placeholder

This aligns more with Chalk.

crates/ra_hir_ty/src/lib.rs

@@ -291,7 +291,7 @@ pub enum Ty {
     /// {}` when we're type-checking the body of that function. In this
     /// situation, we know this stands for *some* type, but don't know the exact
     /// type.
-    Param(TypeParamId),
+    Placeholder(TypeParamId),
 
     /// A bound type variable. This is used in various places: when representing
     /// some polymorphic type like the type of function `fn f<T>`, the type
@@ -365,7 +365,7 @@ impl Substs {
 
     /// Return Substs that replace each parameter by itself (i.e. `Ty::Param`).
     pub(crate) fn type_params_for_generics(generic_params: &Generics) -> Substs {
-        Substs(generic_params.iter().map(|(id, _)| Ty::Param(id)).collect())
+        Substs(generic_params.iter().map(|(id, _)| Ty::Placeholder(id)).collect())
     }
 
     /// Return Substs that replace each parameter by itself (i.e. `Ty::Param`).
@@ -813,7 +813,7 @@ impl TypeWalk for Ty {
                     p.walk(f);
                 }
             }
-            Ty::Param { .. } | Ty::Bound(_) | Ty::Infer(_) | Ty::Unknown => {}
+            Ty::Placeholder { .. } | Ty::Bound(_) | Ty::Infer(_) | Ty::Unknown => {}
         }
         f(self);
     }
@@ -831,7 +831,7 @@ impl TypeWalk for Ty {
                     p.walk_mut_binders(f, binders + 1);
                 }
             }
-            Ty::Param { .. } | Ty::Bound(_) | Ty::Infer(_) | Ty::Unknown => {}
+            Ty::Placeholder { .. } | Ty::Bound(_) | Ty::Infer(_) | Ty::Unknown => {}
         }
         f(self, binders);
     }
@@ -1032,7 +1032,7 @@ impl HirDisplay for Ty {
         match self {
             Ty::Apply(a_ty) => a_ty.hir_fmt(f)?,
             Ty::Projection(p_ty) => p_ty.hir_fmt(f)?,
-            Ty::Param(id) => {
+            Ty::Placeholder(id) => {
                 let generics = generics(f.db, id.parent);
                 let param_data = &generics.params.types[id.local_id];
                 match param_data.provenance {

crates/ra_hir_ty/src/lower.rs

@@ -152,7 +152,7 @@ impl Ty {
                                     data.provenance == TypeParamProvenance::ArgumentImplTrait
                                 })
                                 .nth(idx as usize)
-                                .map_or(Ty::Unknown, |(id, _)| Ty::Param(id));
+                                .map_or(Ty::Unknown, |(id, _)| Ty::Placeholder(id));
                             param
                         } else {
                             Ty::Unknown
@@ -270,7 +270,7 @@ impl Ty {
                 let generics =
                     generics(ctx.db, ctx.resolver.generic_def().expect("generics in scope"));
                 match ctx.type_param_mode {
-                    TypeParamLoweringMode::Placeholder => Ty::Param(param_id),
+                    TypeParamLoweringMode::Placeholder => Ty::Placeholder(param_id),
                     TypeParamLoweringMode::Variable => {
                         let idx = generics.param_idx(param_id).expect("matching generics");
                         Ty::Bound(idx)
@@ -339,7 +339,7 @@ impl Ty {
             None => return Ty::Unknown, // this can't actually happen
         };
         let param_id = match self_ty {
-            Ty::Param(id) if ctx.type_param_mode == TypeParamLoweringMode::Placeholder => id,
+            Ty::Placeholder(id) if ctx.type_param_mode == TypeParamLoweringMode::Placeholder => id,
             Ty::Bound(idx) if ctx.type_param_mode == TypeParamLoweringMode::Variable => {
                 let generics = generics(ctx.db, def);
                 let param_id = if let Some((id, _)) = generics.iter().nth(idx as usize) {
@@ -544,7 +544,7 @@ impl GenericPredicate {
                 let generics = generics(ctx.db, generic_def);
                 let param_id = hir_def::TypeParamId { parent: generic_def, local_id: *param_id };
                 match ctx.type_param_mode {
-                    TypeParamLoweringMode::Placeholder => Ty::Param(param_id),
+                    TypeParamLoweringMode::Placeholder => Ty::Placeholder(param_id),
                     TypeParamLoweringMode::Variable => {
                         let idx = generics.param_idx(param_id).expect("matching generics");
                         Ty::Bound(idx)

crates/ra_hir_ty/src/traits/chalk.rs

@@ -142,7 +142,7 @@ impl ToChalk for Ty {
                 let substitution = proj_ty.parameters.to_chalk(db);
                 chalk_ir::AliasTy { associated_ty_id, substitution }.cast().intern()
             }
-            Ty::Param(id) => {
+            Ty::Placeholder(id) => {
                 let interned_id = db.intern_type_param_id(id);
                 PlaceholderIndex {
                     ui: UniverseIndex::ROOT,
@@ -184,7 +184,7 @@ impl ToChalk for Ty {
                 let interned_id = crate::db::GlobalTypeParamId::from_intern_id(
                     crate::salsa::InternId::from(idx.idx),
                 );
-                Ty::Param(db.lookup_intern_type_param_id(interned_id))
+                Ty::Placeholder(db.lookup_intern_type_param_id(interned_id))
             }
             chalk_ir::TyData::Alias(proj) => {
                 let associated_ty = from_chalk(db, proj.associated_ty_id);