use satisfies

docs/tagged_union_pattern_in_typescript.md

@@ -35,7 +35,7 @@ type ExprWithKind<Tag extends ExprTag> = Expr & { kind: { tag: Tag } };
 
 The type `ExprKind["Tag"]` is a union of each `tag` value, i.e. in this example `"Int" | "Add"`. Saying `Tag extends ExprTag` means that `Tag` (type) is either `"Int"` or `"Add"`, i.e. for `.is("Int")`, `Tag` will be `"Int"` and for `.is("Add")`, `Tag` will be `"Add"`. The *narrowed* type `ExprWithKind` is defined by saying that we want an `Expr` that specifically has the `kind.tag` value of `Tag`.
 
-Then define a methed that with a *type predicate*:
+Then define a method that with a *type predicate*:
 
 ```ts
 class Expr {
@@ -95,7 +95,7 @@ class Expr {
             case "Add":
                 return k.right.eval() + k.left.eval();
         }
-        const _: never = k; // compile time exhaustiveness check
+        k satisfies never; // compile time exhaustiveness check
     }
     // ...
 }
@@ -201,7 +201,7 @@ class Expr {
                 k.right.visit(v);
                 return
         }
-        const _: never = k;
+        k satisfies never;
     }
     // ...
 }

src/mir_interpreter.ts

@@ -134,7 +134,7 @@ export class MirInterpreter {
                     );
                     continue;
             }
-            const _: never = k;
+            k satisfies never;
         }
         return Val.Void;
     }
@@ -158,7 +158,7 @@ class Val {
             case "Fn":
                 return `<${k.fn.ty.pretty()}>`;
         }
-        const _: never = k;
+        k satisfies never;
     }
 }