Merge pull request #140 from sunjay/implallowed

Rename IsLocal to ImplAllowed

Author: nikomatsakis

chalk-parse/src/ast.rs

@@ -218,7 +218,7 @@ pub enum WhereClause {
     UnifyLifetimes { a: Lifetime, b: Lifetime },
     TraitInScope { trait_name: Identifier },
     Derefs { source: Ty, target: Ty },
-    TyIsLocal { ty: Ty },
+    IsLocal { ty: Ty },
 }
 
 pub struct QuantifiedWhereClause {

chalk-parse/src/parser.lalrpop

@@ -273,7 +273,7 @@ WhereClause: WhereClause = {
     "InScope" "(" <t:Id> ")" => WhereClause::TraitInScope { trait_name: t },
     "Derefs" "(" <source:Ty> "," <target:Ty> ")" => WhereClause::Derefs { source, target },
 
-    "IsLocal" "(" <ty:Ty> ")" => WhereClause::TyIsLocal { ty },
+    "IsLocal" "(" <ty:Ty> ")" => WhereClause::IsLocal { ty },
 };
 
 QuantifiedWhereClause: QuantifiedWhereClause = {

src/fold.rs

@@ -425,7 +425,7 @@ enum_fold!(PolarizedTraitRef[] { Positive(a), Negative(a) });
 enum_fold!(ParameterKind[T,L] { Ty(a), Lifetime(a) } where T: Fold, L: Fold);
 enum_fold!(WhereClauseAtom[] { Implemented(a), ProjectionEq(a) });
 enum_fold!(DomainGoal[] { Holds(a), WellFormed(a), FromEnv(a), Normalize(a), UnselectedNormalize(a),
-                          WellFormedTy(a), FromEnvTy(a), InScope(a), Derefs(a), IsLocalTy(a), IsLocalTraitRef(a) });
+                          WellFormedTy(a), FromEnvTy(a), InScope(a), Derefs(a), IsLocal(a), LocalImplAllowed(a) });
 enum_fold!(LeafGoal[] { EqGoal(a), DomainGoal(a) });
 enum_fold!(Constraint[] { LifetimeEq(a, b) });
 enum_fold!(Goal[] { Quantified(qkind, subgoal), Implies(wc, subgoal), And(g1, g2), Not(g),

src/ir.rs

@@ -269,7 +269,7 @@ pub enum InlineBound {
 
 impl InlineBound {
     /// Applies the `InlineBound` to `self_ty` and lowers to a [`DomainGoal`].
-    /// 
+    ///
     /// Because an `InlineBound` does not know anything about what it's binding,
     /// you must provide that type as `self_ty`.
     crate fn lower_with_self(&self, self_ty: Ty) -> Vec<DomainGoal> {
@@ -691,8 +691,16 @@ pub enum DomainGoal {
     /// True if a type is considered to have been "defined" by the current crate. This is true for
     /// a `struct Foo { }` but false for a `extern struct Foo { }`. However, for fundamental types
     /// like `Box<T>`, it is true if `T` is local.
-    IsLocalTy(Ty),
-    IsLocalTraitRef(TraitRef),
+    IsLocal(Ty),
+
+    /// Used to dictate when trait impls are allowed in the current (local) crate based on the
+    /// orphan rules.
+    ///
+    /// `LocalImplAllowed(T: Trait)` is true if the type T is allowed to impl trait Trait in
+    /// the current crate. Under the current rules, this is unconditionally true for all types if
+    /// the Trait is considered to be "defined" in the current crate. If that is not the case, then
+    /// `LocalImplAllowed(T: Trait)` can still be true if `IsLocal(T)` is true.
+    LocalImplAllowed(TraitRef),
 }
 
 pub type QuantifiedDomainGoal = Binders<DomainGoal>;

src/ir/debug.rs

@@ -206,8 +206,8 @@ impl Debug for DomainGoal {
             DomainGoal::FromEnvTy(t) => write!(fmt, "FromEnv({:?})", t),
             DomainGoal::InScope(n) => write!(fmt, "InScope({:?})", n),
             DomainGoal::Derefs(n) => write!(fmt, "Derefs({:?})", n),
-            DomainGoal::IsLocalTy(n) => write!(fmt, "IsLocalTy({:?})", n),
-            DomainGoal::IsLocalTraitRef(n) => write!(fmt, "IsLocalTraitRef({:?})", n),
+            DomainGoal::IsLocal(n) => write!(fmt, "IsLocal({:?})", n),
+            DomainGoal::LocalImplAllowed(n) => write!(fmt, "LocalImplAllowed({:?})", n),
         }
     }
 }

src/ir/lowering.rs

@@ -494,8 +494,8 @@ impl LowerWhereClause<ir::DomainGoal> for WhereClause {
                     target: target.lower(env)?
                 })
             ],
-            WhereClause::TyIsLocal { ty } => vec![
-                ir::DomainGoal::IsLocalTy(ty.lower(env)?)
+            WhereClause::IsLocal { ty } => vec![
+                ir::DomainGoal::IsLocal(ty.lower(env)?)
             ],
         };
         Ok(goals)
@@ -527,7 +527,7 @@ impl LowerWhereClause<ir::LeafGoal> for WhereClause {
             | WhereClause::TyFromEnv { .. }
             | WhereClause::TraitRefFromEnv { .. }
             | WhereClause::Derefs { .. }
-            | WhereClause::TyIsLocal { .. } => {
+            | WhereClause::IsLocal { .. } => {
                 let goals: Vec<ir::DomainGoal> = self.lower(env)?;
                 goals.into_iter().casted().collect()
             }

src/rules.rs

@@ -294,7 +294,7 @@ impl ir::StructDatum {
         //
         // If the type Foo is not marked `extern`, we also generate:
         //
-        //    forall<T> { IsLocalTy(Foo<T>) }
+        //    forall<T> { IsLocal(Foo<T>) }
         //
         // Given an `extern` type that is also fundamental:
         //
@@ -303,7 +303,7 @@ impl ir::StructDatum {
         //
         // We generate the following clause:
         //
-        //    forall<T> { IsLocalTy(Box<T>) :- IsLocalTy(T) }
+        //    forall<T> { IsLocal(Box<T>) :- IsLocal(T) }
 
         let wf = self.binders.map_ref(|bound_datum| {
             ir::ProgramClauseImplication {
@@ -323,16 +323,16 @@ impl ir::StructDatum {
 
         // Types that are not marked `extern` satisfy IsLocal(TypeName)
         if !self.binders.value.flags.external {
-            // `IsLocalTy(Ty)` depends *only* on whether the type is marked extern and nothing else
+            // `IsLocal(Ty)` depends *only* on whether the type is marked extern and nothing else
             let is_local = self.binders.map_ref(|bound_datum| ir::ProgramClauseImplication {
-                consequence: ir::DomainGoal::IsLocalTy(bound_datum.self_ty.clone().cast()),
+                consequence: ir::DomainGoal::IsLocal(bound_datum.self_ty.clone().cast()),
                 conditions: Vec::new(),
             }).cast();
 
             clauses.push(is_local);
         } else if self.binders.value.flags.fundamental {
-            // If a type is `extern`, but is also `#[fundamental]`, it satisfies IsLocalTy
-            // if and only if its parameters satisfy IsLocalTy
+            // If a type is `extern`, but is also `#[fundamental]`, it satisfies IsLocal
+            // if and only if its parameters satisfy IsLocal
 
             // Fundamental types must always have at least one type parameter for this rule to
             // make any sense. We currently do not have have any fundamental types with more than
@@ -343,9 +343,9 @@ impl ir::StructDatum {
                 "Only fundamental types with a single parameter are supported");
 
             let local_fundamental = self.binders.map_ref(|bound_datum| ir::ProgramClauseImplication {
-                consequence: ir::DomainGoal::IsLocalTy(bound_datum.self_ty.clone().cast()),
+                consequence: ir::DomainGoal::IsLocal(bound_datum.self_ty.clone().cast()),
                 conditions: vec![
-                    ir::DomainGoal::IsLocalTy(
+                    ir::DomainGoal::IsLocal(
                         // This unwrap is safe because we asserted above for the presence of a type
                         // parameter
                         bound_datum.self_ty.first_type_parameter().unwrap()

src/rules/wf.rs

@@ -143,8 +143,8 @@ impl FoldInputTypes for DomainGoal {
             DomainGoal::FromEnv(..) |
             DomainGoal::WellFormedTy(..) |
             DomainGoal::FromEnvTy(..) |
-            DomainGoal::IsLocalTy(..) |
-            DomainGoal::IsLocalTraitRef(..) |
+            DomainGoal::IsLocal(..) |
+            DomainGoal::LocalImplAllowed(..) |
             DomainGoal::Derefs(..) => panic!("unexpected where clause"),
 
             DomainGoal::InScope(..) => (),

src/zip.rs

@@ -227,8 +227,8 @@ enum_zip!(DomainGoal {
     FromEnvTy,
     InScope,
     Derefs,
-    IsLocalTy,
-    IsLocalTraitRef
+    IsLocal,
+    LocalImplAllowed
 });
 enum_zip!(LeafGoal { DomainGoal, EqGoal });
 enum_zip!(ProgramClause { Implies, ForAll });