Tweak inline bounds on associated types in the grammar

Author: scalexm

chalk-parse/src/ast.rs

@@ -54,7 +54,7 @@ pub struct TraitFlags {
 pub struct AssocTyDefn {
     pub name: Identifier,
     pub parameter_kinds: Vec<ParameterKind>,
-    pub bounds: Vec<TraitBound>,
+    pub bounds: Vec<InlineBound>,
     pub where_clauses: Vec<QuantifiedWhereClause>,
 }
 
@@ -68,20 +68,23 @@ pub enum Parameter {
     Lifetime(Lifetime),
 }
 
+/// An inline bound, e.g. `: Foo<K>` in `impl<K, T: Foo<K>> SomeType<T>`.
+pub enum InlineBound {
+    TraitBound(TraitBound),
+    ProjectionEqBound(ProjectionEqBound),
+}
+
 /// Represents a trait bound on e.g. a type or type parameter.
 /// Does not know anything about what it's binding.
 pub struct TraitBound {
     pub trait_name: Identifier,
-    pub args_no_self: Vec<TraitBoundParameter>,
-}
-
-pub enum TraitBoundParameter {
-    Ty(Ty),
-    Lifetime(Lifetime),
-    ProjectionEq(ProjectionEqBound),
+    pub args_no_self: Vec<Parameter>,
 }
 
+/// Represents a projection equality bound on e.g. a type or type parameter.
+/// Does not know anything about what it's binding.
 pub struct ProjectionEqBound {
+    pub trait_bound: TraitBound,
     pub name: Identifier,
     pub parameters: Vec<Parameter>,
     pub value: Ty,

chalk-parse/src/parser.lalrpop

@@ -72,7 +72,7 @@ TraitDefn: TraitDefn = {
 };
 
 AssocTyDefn: AssocTyDefn = {
-    "type" <name:Id> <p:Angle<ParameterKind>> <b:(":" <Plus<TraitBound>>)?>
+    "type" <name:Id> <p:Angle<ParameterKind>> <b:(":" <Plus<InlineBound>>)?>
         <w:QuantifiedWhereClauses> ";" =>
     {
         AssocTyDefn {
@@ -84,25 +84,32 @@ AssocTyDefn: AssocTyDefn = {
     }
 };
 
+InlineBound: InlineBound = {
+    TraitBound => InlineBound::TraitBound(<>),
+    ProjectionEqBound => InlineBound::ProjectionEqBound(<>),
+};
+
 TraitBound: TraitBound = {
-    <t:Id> <a:Angle<TraitBoundParameter>> => {
+    <t:Id> <a:Angle<Parameter>> => {
         TraitBound {
             trait_name: t,
             args_no_self: a,
         }
     }
 };
 
-TraitBoundParameter: TraitBoundParameter = {
-    Ty => TraitBoundParameter::Ty(<>),
-    Lifetime => TraitBoundParameter::Lifetime(<>),
-    ProjectionEqBound => TraitBoundParameter::ProjectionEq(<>),
-};
-
 ProjectionEqBound: ProjectionEqBound = {
-    <name:Id> <parameters:Angle<Parameter>> "=" <value:Ty> => ProjectionEqBound {
-        name, parameters, value
-    },
+    <t:Id> "<" <a:(<Comma<Parameter>> ",")?> <name:Id> <a2:Angle<Parameter>>
+        "=" <ty:Ty> ">" => ProjectionEqBound
+    {
+        trait_bound: TraitBound {
+            trait_name: t,
+            args_no_self: a.unwrap_or(vec![]),
+        },
+        name,
+        parameters: a2,
+        value: ty,
+    }
 };
 
 Impl: Impl = {

src/ir/lowering/mod.rs

@@ -70,7 +70,7 @@ impl<'k> Env<'k> {
     /// Introduces new parameters, shifting the indices of existing
     /// parameters to accommodate them. The indices of the new binders
     /// will be assigned in order as they are iterated.
-    fn introduce<I>(&self, binders: I) -> Self
+    fn introduce<I>(&self, binders: I) -> Result<Self>
     where
         I: IntoIterator<Item = ir::ParameterKind<ir::Identifier>>,
         I::IntoIter: ExactSizeIterator,
@@ -82,10 +82,13 @@ impl<'k> Env<'k> {
             .map(|(&k, &v)| (k, v + len))
             .chain(binders)
             .collect();
-        Env {
+        if parameter_map.len() != self.parameter_map.len() + len {
+            bail!("duplicate parameters");
+        }
+        Ok(Env {
             parameter_map,
             ..*self
-        }
+        })
     }
 
     fn in_binders<I, T, OP>(&self, binders: I, op: OP) -> Result<ir::Binders<T>>
@@ -95,7 +98,7 @@ impl<'k> Env<'k> {
         OP: FnOnce(&Self) -> Result<T>,
     {
         let binders: Vec<_> = binders.into_iter().collect();
-        let env = self.introduce(binders.iter().cloned());
+        let env = self.introduce(binders.iter().cloned())?;
         Ok(ir::Binders {
             binders: binders.anonymize(),
             value: op(&env)?,
@@ -178,6 +181,7 @@ impl LowerProgram for Program {
 
                         let mut parameter_kinds = defn.all_parameters();
                         parameter_kinds.extend(d.all_parameters());
+                        let env = empty_env.introduce(parameter_kinds.clone())?;
 
                         associated_ty_data.insert(
                             info.id,
@@ -186,7 +190,7 @@ impl LowerProgram for Program {
                                 id: info.id,
                                 name: defn.name.str,
                                 parameter_kinds: parameter_kinds,
-                                where_clauses: vec![],
+                                where_clauses: defn.where_clauses.lower(&env)?,
                             },
                         );
                     }
@@ -757,7 +761,7 @@ impl LowerTy for Ty {
                     lifetime_names
                         .iter()
                         .map(|id| ir::ParameterKind::Lifetime(id.str)),
-                );
+                )?;
 
                 let ty = ty.lower(&quantified_env)?;
                 let quantified_ty = ir::QuantifiedTy {

src/ir/lowering/test.rs

@@ -305,9 +305,8 @@ fn check_parameter_kinds() {
 
 #[test]
 fn gat_parse() {
-    let program = Arc::new(
-        parse_and_lower_program(
-            "
+    lowering_success! {
+        program {
             trait Sized {}
 
             trait Foo {
@@ -323,17 +322,51 @@ fn gat_parse() {
             }
 
             trait Baz {
-                type Item<'a, 'b, T>: Foo<Item<'b, T> = Containter<T>> + Clone;
+                type Item<'a, 'b, T>: Foo<Item<'b, T> = Container<T>> + Clone;
             }
 
             trait Quux {
                 type Item<'a, T>;
             }
-            ",
-            SolverChoice::slg()
-        ).unwrap()
-    );
-    tls::set_current_program(&program, || {
-        println!("{:#?}", program.associated_ty_data.values());
-    });
+        }
+    }
+
+    lowering_error! {
+        program {
+            trait Sized { }
+
+            trait Foo {
+                type Item where K: Sized;
+            }
+        }
+
+        error_msg {
+            "invalid type name `K`"
+        }
+    }
+}
+
+#[test]
+fn duplicate_parameters() {
+    lowering_error! {
+        program {
+            trait Foo<T, T> { }
+        }
+
+        error_msg {
+            "duplicate parameters"
+        }
+    }
+
+    lowering_error! {
+        program {
+            trait Foo<T> {
+                type Item<T>;
+            }
+        }
+
+        error_msg {
+            "duplicate parameters"
+        }
+    }
 }

src/ir/mod.rs

@@ -273,8 +273,10 @@ pub struct AssociatedTyDatum {
     /// but possibly including more.
     crate parameter_kinds: Vec<ParameterKind<Identifier>>,
 
+    // FIXME: inline bounds on the associated ty need to be implemented
+
     /// Where clauses that must hold for the projection be well-formed.
-    crate where_clauses: Vec<DomainGoal>,
+    crate where_clauses: Vec<QuantifiedDomainGoal>,
 }
 
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]

src/lib.rs

@@ -3,13 +3,11 @@
 #![feature(catch_expr)]
 #![feature(crate_in_paths)]
 #![feature(crate_visibility_modifier)]
-#![feature(dyn_trait)]
 #![feature(in_band_lifetimes)]
 #![feature(macro_at_most_once_rep)]
 #![feature(macro_vis_matcher)]
 #![feature(specialization)]
 #![feature(step_trait)]
-#![feature(underscore_lifetimes)]
 
 extern crate chalk_parse;
 #[macro_use]