Parse and lower never type

Author: nathanwhit

chalk-integration/src/lowering.rs

@@ -1427,6 +1427,12 @@ impl LowerTy for Ty {
                 substitution: chalk_ir::Substitution::empty(interner),
             })
             .intern(interner)),
+
+            Ty::Never => Ok(chalk_ir::TyData::Apply(chalk_ir::ApplicationTy {
+                name: chalk_ir::TypeName::Never,
+                substitution: chalk_ir::Substitution::empty(interner),
+            })
+            .intern(interner)),
         }
     }
 }

chalk-parse/src/ast.rs

@@ -222,6 +222,7 @@ pub enum Ty {
         ty: Box<Ty>,
     },
     Str,
+    Never,
 }
 
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]

chalk-parse/src/parser.lalrpop

@@ -224,6 +224,7 @@ TyWithoutId: Ty = {
     },
     <ScalarType> => Ty::Scalar { ty: <> },
     "str" => Ty::Str,
+    "!" => Ty::Never,
     "fn" "(" <t:Ty> ")" => Ty::ForAll {
         lifetime_names: vec![],
         ty: Box::new(t)