diff --git a/src/Psl/Dict/map.php b/src/Psl/Dict/map.php
index 868f7912..5033b3bb 100644
--- a/src/Psl/Dict/map.php
+++ b/src/Psl/Dict/map.php
@@ -26,7 +26,7 @@
  * @param iterable<Tk, Tv> $iterable Iterable to be mapped over
  * @param (Closure(Tv): T) $function
  *
- * @return array<Tk, T>
+ * @return ($iterable is non-empty-array ? non-empty-array<Tk, T> : array<Tk, T>)
  */
 function map(iterable $iterable, Closure $function): array
 {
diff --git a/src/Psl/Dict/map_keys.php b/src/Psl/Dict/map_keys.php
index 25cb35a9..1f999179 100644
--- a/src/Psl/Dict/map_keys.php
+++ b/src/Psl/Dict/map_keys.php
@@ -26,7 +26,7 @@
  * @param iterable<Tk1, Tv> $iterable Iterable to be mapped over
  * @param (Closure(Tk1): Tk2) $function
  *
- * @return array<Tk2, Tv>
+ * @return ($iterable is non-empty-array ? non-empty-array<Tk2, Tv> : array<Tk2, Tv>)
  */
 function map_keys(iterable $iterable, Closure $function): array
 {
diff --git a/src/Psl/Dict/map_with_key.php b/src/Psl/Dict/map_with_key.php
index bf756f6c..746c5d36 100644
--- a/src/Psl/Dict/map_with_key.php
+++ b/src/Psl/Dict/map_with_key.php
@@ -26,7 +26,7 @@
  * @param iterable<Tk, Tv> $iterable Iterable to be mapped over
  * @param (Closure(Tk,Tv): T) $function
  *
- * @return array<Tk, T>
+ * @return ($iterable is non-empty-array ? non-empty-array<Tk, T> : array<Tk, T>)
  */
 function map_with_key(iterable $iterable, Closure $function): array
 {
diff --git a/src/Psl/Vec/map.php b/src/Psl/Vec/map.php
index b9f404b7..d7e2a8f4 100644
--- a/src/Psl/Vec/map.php
+++ b/src/Psl/Vec/map.php
@@ -28,7 +28,7 @@
  * @param iterable<Tk, Tv> $iterable Iterable to be mapped over
  * @param (Closure(Tv): T) $function
  *
- * @return list<T>
+ * @return ($iterable is non-empty-array ? non-empty-list<T> : list<T>)
  */
 function map(iterable $iterable, Closure $function): array
 {
diff --git a/src/Psl/Vec/map_with_key.php b/src/Psl/Vec/map_with_key.php
index 5f11a095..e4c97780 100644
--- a/src/Psl/Vec/map_with_key.php
+++ b/src/Psl/Vec/map_with_key.php
@@ -24,7 +24,7 @@
  * @param iterable<Tk, Tv> $iterable Iterable to be mapped over
  * @param (Closure(Tk,Tv): T) $function
  *
- * @return list<T>
+ * @return ($iterable is non-empty-array ? non-empty-list<T> : list<T>)
  */
 function map_with_key(iterable $iterable, Closure $function): array
 {