fix

Author: KiaraGrouwstra

src/compiler/types.ts

@@ -3395,7 +3395,7 @@ namespace ts {
     }
 
     // type spread types (TypeFlags.TypeSpread)
-    export interface TypeSpreadType extends TypeVariable {
+    export interface TypeSpreadType extends Type {
         type: Type;
     }
 

tests/cases/compiler/tupleTypeSpreadErrors.ts

@@ -0,0 +1 @@
+type Boom<T extends string> = [...T];