Fix STM unification (#4412)

Effect-TS · Feb 6, 2025 · e30f132 · e30f132
1 parent 58a6f9d
commit e30f132
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Showing 3 changed files with 17 additions and 2 deletions.
diff --git a/.changeset/beige-rules-play.md b/.changeset/beige-rules-play.md
@@ -0,0 +1,5 @@
+---
+"effect": patch
+---
+
+Fix STM unification
diff --git a/packages/effect/dtslint/Unify.ts b/packages/effect/dtslint/Unify.ts
@@ -14,6 +14,7 @@ import type * as RcRef from "effect/RcRef"
 import type * as Ref from "effect/Ref"
 import type * as Resource from "effect/Resource"
 import type * as ScopedRef from "effect/ScopedRef"
+import type * as STM from "effect/STM"
 import type * as Stream from "effect/Stream"
 import type * as SubscriptionRef from "effect/SubscriptionRef"
 import type * as SynchronizedRef from "effect/SynchronizedRef"
@@ -62,6 +63,13 @@ hole<
     | Effect.Effect<"a", "b", "c">
   >
 >()
+// $ExpectType STM<0 | "a", "b" | 1, "c" | 2>
+hole<
+  Unify.Unify<
+    | STM.STM<0, 1, 2>
+    | STM.STM<"a", "b", "c">
+  >
+>()
 
 // $ExpectType Exit<0 | "a", "b" | 1>
 hole<
@@ -182,7 +190,7 @@ hole<
   >
 >()
 
-// $ExpectType 0 | Option<string | number> | Ref<1> | Ref<"a"> | SynchronizedRef<1> | SynchronizedRef<"a"> | SubscriptionRef<1> | SubscriptionRef<"a"> | Deferred<"a", "b"> | FiberRef<1> | FiberRef<"a"> | ManagedRuntime<"a", "b"> | Queue<1> | Queue<"a"> | Dequeue<"a" | 1> | Pool<1, 2> | Pool<"a", "b" | "c"> | ScopedRef<1> | ScopedRef<"a"> | Resource<"a", "b"> | Deferred<1, 0> | Resource<1, 0> | Latch | ManagedRuntime<1, 0> | RcRef<"a" | 1, 0 | "b"> | Fiber<"a" | 1, 0 | "b"> | RuntimeFiber<"a" | 1, 0 | "b"> | Either<"a" | 1, 0 | "b"> | Effect<"a" | 1, 0 | "b", "R" | "R1">
+// $ExpectType 0 | Option<string | number> | STM<0 | "a", "b" | 1, "c" | 2> | Ref<1> | Ref<"a"> | SynchronizedRef<1> | SynchronizedRef<"a"> | SubscriptionRef<1> | SubscriptionRef<"a"> | Deferred<"a", "b"> | FiberRef<1> | FiberRef<"a"> | ManagedRuntime<"a", "b"> | Queue<1> | Queue<"a"> | Dequeue<"a" | 1> | Pool<1, 2> | Pool<"a", "b" | "c"> | ScopedRef<1> | ScopedRef<"a"> | Resource<"a", "b"> | Deferred<1, 0> | Resource<1, 0> | Latch | ManagedRuntime<1, 0> | RcRef<"a" | 1, 0 | "b"> | Fiber<"a" | 1, 0 | "b"> | RuntimeFiber<"a" | 1, 0 | "b"> | Either<"a" | 1, 0 | "b"> | Effect<"a" | 1, 0 | "b", "R" | "R1">
 hole<
   Unify.Unify<
     | Either.Either<1, 0>
@@ -191,6 +199,8 @@ hole<
     | Option.Option<string>
     | Effect.Effect<"a", "b", "R">
     | Effect.Effect<1, 0, "R1">
+    | STM.STM<0, 1, 2>
+    | STM.STM<"a", "b", "c">
     | Ref.Ref<1>
     | Ref.Ref<"a">
     | SynchronizedRef.SynchronizedRef<1>

diff --git a/packages/effect/src/STM.ts b/packages/effect/src/STM.ts
@@ -81,7 +81,7 @@ export interface STM<out A, out E = never, out R = never>
  * @category models
  */
 export interface STMUnify<A extends { [Unify.typeSymbol]?: any }> extends Effect.EffectUnify<A> {
-  STM?: () => A[Unify.typeSymbol] extends STM<infer A0, infer E0, infer R0> | infer _ ? STM<R0, E0, A0> : never
+  STM?: () => A[Unify.typeSymbol] extends STM<infer A0, infer E0, infer R0> | infer _ ? STM<A0, E0, R0> : never
 }
 
 /**