Add Never to TypeName

Author: nathanwhit

chalk-ir/src/debug.rs

@@ -167,6 +167,7 @@ impl<I: Interner> Debug for TypeName<I> {
             TypeName::FnDef(fn_def) => write!(fmt, "{:?}", fn_def),
             TypeName::Raw(mutability) => write!(fmt, "{:?}", mutability),
             TypeName::Ref(mutability) => write!(fmt, "{:?}", mutability),
+            TypeName::Never => write!(fmt, "Never"),
             TypeName::Error => write!(fmt, "{{error}}"),
         }
     }

chalk-ir/src/lib.rs

@@ -175,6 +175,9 @@ pub enum TypeName<I: Interner> {
     /// the string primitive type
     Str,
 
+    /// the never type `!`
+    Never,
+
     /// This can be used to represent an error, e.g. during name resolution of a type.
     /// Chalk itself will not produce this, just pass it through when given.
     Error,

chalk-solve/src/clauses.rs

@@ -404,20 +404,19 @@ fn match_type_name<I: Interner>(
             .db
             .associated_ty_data(type_id)
             .to_program_clauses(builder),
-        TypeName::Scalar(_) => {
-            builder.push_fact(WellFormed::Ty(application.clone().intern(interner)))
-        }
-        TypeName::Str => builder.push_fact(WellFormed::Ty(application.clone().intern(interner))),
-        TypeName::Tuple(_) => {
-            builder.push_fact(WellFormed::Ty(application.clone().intern(interner)))
-        }
-        TypeName::Slice => builder.push_fact(WellFormed::Ty(application.clone().intern(interner))),
-        TypeName::Raw(_) => builder.push_fact(WellFormed::Ty(application.clone().intern(interner))),
-        TypeName::Ref(_) => builder.push_fact(WellFormed::Ty(application.clone().intern(interner))),
         TypeName::FnDef(fn_def_id) => builder
             .db
             .fn_def_datum(fn_def_id)
             .to_program_clauses(builder),
+        TypeName::Tuple(_)
+        | TypeName::Scalar(_)
+        | TypeName::Str
+        | TypeName::Slice
+        | TypeName::Raw(_)
+        | TypeName::Ref(_)
+        | TypeName::Never => {
+            builder.push_fact(WellFormed::Ty(application.clone().intern(interner)))
+        }
     }
 }