From 76e6ece55b21394d4d16ed8718b6212e34c3b9cd Mon Sep 17 00:00:00 2001
From: Misha Kaletsky <mmkal@users.noreply.github.com>
Date: Tue, 3 Oct 2023 09:07:57 -0400
Subject: [PATCH] improve vanilla array handling

---
 src/index.ts                           | 14 ++++++++------
 test/__snapshots__/errors.test.ts.snap |  5 ++---
 2 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/src/index.ts b/src/index.ts
index 90534bf..ad08932 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -54,12 +54,14 @@ export type UsefulKeys<T> = T extends any[]
 // This swaps "leaf" types with a literal message about what the actual and expected types are.
 // Needs to check for Not<IsAny<Actual>> because otherwise LeafTypeOf<Actual> returns never, which extends everything 🤔
 export type MismatchInfo<Actual, Expected> = And<[Extends<PrintType<Actual>, '...'>, Not<IsAny<Actual>>]> extends true
-  ? {
-      [K in UsefulKeys<Actual> | UsefulKeys<Expected>]: MismatchInfo<
-        K extends keyof Actual ? Actual[K] : never,
-        K extends keyof Expected ? Expected[K] : never
-      >
-    }
+  ? And<[Extends<any[], Actual>, Extends<any[], Expected>]> extends true
+    ? Array<MismatchInfo<Extract<Actual, any[]>[number], Extract<Expected, any[]>[number]>>
+    : {
+        [K in UsefulKeys<Actual> | UsefulKeys<Expected>]: MismatchInfo<
+          K extends keyof Actual ? Actual[K] : never,
+          K extends keyof Expected ? Expected[K] : never
+        >
+      }
   : StrictEqualUsingBranding<Actual, Expected> extends true
   ? Actual
   : `Expected: ${PrintType<Expected>}, Actual: ${PrintType<Exclude<Actual, Expected>>}`
diff --git a/test/__snapshots__/errors.test.ts.snap b/test/__snapshots__/errors.test.ts.snap
index de54d98..5c2563d 100644
--- a/test/__snapshots__/errors.test.ts.snap
+++ b/test/__snapshots__/errors.test.ts.snap
@@ -148,9 +148,8 @@ test/usage.test.ts:999:999 - error TS2349: This expression is not callable.
 
 999   expectTypeOf([1, 2, 3]).items.toBeString()
                                     ~~~~~~~~~~
-test/usage.test.ts:999:999 - error TS2344: Type 'number[]' does not satisfy the constraint '{ [x: number]: never; }'.
-  'number' index signatures are incompatible.
-    Type 'number' is not assignable to type 'never'.
+test/usage.test.ts:999:999 - error TS2344: Type 'number[]' does not satisfy the constraint 'never[]'.
+  Type 'number' is not assignable to type 'never'.
 
 999   expectTypeOf<any[]>().toEqualTypeOf<number[]>()
                                           ~~~~~~~~