From b6d791a79bc38846dc8d150a867007c084306862 Mon Sep 17 00:00:00 2001
From: gvergnaud <gabriel.vergnaud@gmail.com>
Date: Sat, 14 Dec 2024 18:30:39 -0500
Subject: [PATCH] feat(P.infer): Remove inference point

---
 package-lock.json         | 14 +++++++-------
 package.json              |  2 +-
 src/patterns.ts           | 10 +++-------
 src/types/FindSelected.ts |  2 +-
 tests/infer.test.ts       | 17 +++++++++++++++++
 tests/not.test.ts         |  4 +++-
 6 files changed, 32 insertions(+), 17 deletions(-)

diff --git a/package-lock.json b/package-lock.json
index 4aaf7230..7abd1429 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -15,7 +15,7 @@
         "prettier": "^2.8.8",
         "rimraf": "^5.0.1",
         "ts-jest": "^29.1.2",
-        "typescript": "^5.3.3"
+        "typescript": "^5.7.2"
       }
     },
     "node_modules/@babel/code-frame": {
@@ -8230,9 +8230,9 @@
       }
     },
     "node_modules/typescript": {
-      "version": "5.3.3",
-      "resolved": "https://registry.npmjs.org/typescript/-/typescript-5.3.3.tgz",
-      "integrity": "sha512-pXWcraxM0uxAS+tN0AG/BF2TyqmHO014Z070UsJ+pFvYuRSq8KH8DmWpnbXe0pEPDHXZV3FcAbJkijJ5oNEnWw==",
+      "version": "5.7.2",
+      "resolved": "https://registry.npmjs.org/typescript/-/typescript-5.7.2.tgz",
+      "integrity": "sha512-i5t66RHxDvVN40HfDd1PsEThGNnlMCMT3jMUuoh9/0TaqWevNontacunWyN02LA9/fIbEWlcHZcgTKb9QoaLfg==",
       "dev": true,
       "bin": {
         "tsc": "bin/tsc",
@@ -14487,9 +14487,9 @@
       }
     },
     "typescript": {
-      "version": "5.3.3",
-      "resolved": "https://registry.npmjs.org/typescript/-/typescript-5.3.3.tgz",
-      "integrity": "sha512-pXWcraxM0uxAS+tN0AG/BF2TyqmHO014Z070UsJ+pFvYuRSq8KH8DmWpnbXe0pEPDHXZV3FcAbJkijJ5oNEnWw==",
+      "version": "5.7.2",
+      "resolved": "https://registry.npmjs.org/typescript/-/typescript-5.7.2.tgz",
+      "integrity": "sha512-i5t66RHxDvVN40HfDd1PsEThGNnlMCMT3jMUuoh9/0TaqWevNontacunWyN02LA9/fIbEWlcHZcgTKb9QoaLfg==",
       "dev": true
     },
     "unbox-primitive": {
diff --git a/package.json b/package.json
index 06aabb0e..46abf550 100644
--- a/package.json
+++ b/package.json
@@ -75,6 +75,6 @@
     "prettier": "^2.8.8",
     "rimraf": "^5.0.1",
     "ts-jest": "^29.1.2",
-    "typescript": "^5.3.3"
+    "typescript": "^5.7.2"
   }
 }
diff --git a/src/patterns.ts b/src/patterns.ts
index b08d8dfd..9f04b2e3 100644
--- a/src/patterns.ts
+++ b/src/patterns.ts
@@ -92,10 +92,7 @@ export type unstable_Matcher<
  * const userPattern = { name: P.string }
  * type User = P.infer<typeof userPattern>
  */
-export type infer<pattern extends Pattern<any>> = InvertPattern<
-  pattern,
-  unknown
->;
+export type infer<pattern> = InvertPattern<NoInfer<pattern>, unknown>;
 
 /**
  * `P.narrow<Input, Pattern>` will narrow the input type to only keep
@@ -110,9 +107,8 @@ export type infer<pattern extends Pattern<any>> = InvertPattern<
  * type Narrowed = P.narrow<Input, typeof Pattern>
  * //     ^? ['a', 'a' | 'b']
  */
-export type narrow<input, pattern extends Pattern<any>> = ExtractPreciseValue<
-  input,
-  InvertPattern<pattern, input>
+export type narrow<input, pattern extends Pattern<any>> = NoInfer<
+  ExtractPreciseValue<input, InvertPattern<pattern, input>>
 >;
 
 function chainable<pattern extends Matcher<any, any, any, any, any>>(
diff --git a/src/types/FindSelected.ts b/src/types/FindSelected.ts
index c2ac5b92..67603554 100644
--- a/src/types/FindSelected.ts
+++ b/src/types/FindSelected.ts
@@ -166,4 +166,4 @@ export type FindSelected<i, p> =
   // This happens if the provided pattern didn't extend Pattern<i>,
   // Because the type checker falls back on the general `Pattern<i>` type
   // in this case.
-  Equal<p, Pattern<i>> extends true ? i : Selections<i, p>;
+  NoInfer<Equal<p, Pattern<i>> extends true ? i : Selections<i, p>>;
diff --git a/tests/infer.test.ts b/tests/infer.test.ts
index 3a2c9c6e..8ba255fa 100644
--- a/tests/infer.test.ts
+++ b/tests/infer.test.ts
@@ -22,4 +22,21 @@ describe('P.infer', () => {
       type test2 = Expect<Equal<QuizState, expected2>>;
     });
   });
+
+  it("P.infer shouldn't count as an inference point of the pattern", () => {
+    const getValueOfType = <T extends P.Pattern<unknown>>(
+      obj: unknown,
+      path: string,
+      pattern: T,
+      defaultValue: P.infer<T>
+    ): P.infer<T> => defaultValue;
+
+    getValueOfType(
+      null,
+      'a.b.c',
+      { x: P.string },
+      // @ts-expect-error 👇 error should be here
+      'oops'
+    );
+  });
 });
diff --git a/tests/not.test.ts b/tests/not.test.ts
index 4accb525..283115f9 100644
--- a/tests/not.test.ts
+++ b/tests/not.test.ts
@@ -110,7 +110,9 @@ describe('not', () => {
         .exhaustive()
     ).toBe('hello');
 
-    const untypedNullable = P.when((x) => x === null || x === undefined);
+    const untypedNullable = P.when(
+      (x): boolean => x === null || x === undefined
+    );
 
     expect(
       match<{ str: string }>({ str: 'hello' })