Add parse rules for GATs

Author: tmandry

chalk-parse/src/ast.rs

@@ -54,6 +54,8 @@ pub struct TraitFlags {
 pub struct AssocTyDefn {
     pub name: Identifier,
     pub parameter_kinds: Vec<ParameterKind>,
+    pub bound: Option<TraitRef>,
+    pub where_clauses: Vec<QuantifiedWhereClause>,
 }
 
 pub enum ParameterKind {

chalk-parse/src/parser.lalrpop

@@ -72,9 +72,26 @@ TraitDefn: TraitDefn = {
 };
 
 AssocTyDefn: AssocTyDefn = {
-    "type" <name:Id> <p:Angle<ParameterKind>> ";" => AssocTyDefn {
-        name: name,
-        parameter_kinds: p
+    "type" <name:Id> <p:Angle<ParameterKind>> <b:(":" <Id> <Angle<Parameter>>)?>
+        <w:QuantifiedWhereClauses> ";" =>
+    {
+        let bound = match b {
+            Some((t, a)) => {
+                let mut args = vec![Parameter::Ty(Ty::Id{ name })];
+                args.extend(a);
+                Some(TraitRef {
+                    trait_name: t,
+                    args: args,
+                })
+            }
+            None => None
+        };
+        AssocTyDefn {
+            name: name,
+            parameter_kinds: p,
+            where_clauses: w,
+            bound,
+        }
     }
 };
 

src/ir/lowering/test.rs

@@ -302,3 +302,34 @@ fn check_parameter_kinds() {
         }
     }
 }
+
+#[test]
+fn gat_parse() {
+    let program = Arc::new(
+        parse_and_lower_program(
+            "
+            trait Sized {}
+
+            trait Foo {
+                type Item<'a, T>: Clone where Self: Sized;
+            }
+
+            trait Bar {
+                type Item<'a, T> where Self: Sized;
+            }
+
+            trait Baz {
+                type Item<'a, T>: Clone;
+            }
+
+            trait Quux {
+                type Item<'a, T>;
+            }
+            ",
+            SolverChoice::slg()
+        ).unwrap()
+    );
+    tls::set_current_program(&program, || {
+        println!("{:#?}", program.associated_ty_data.values());
+    });
+}