Fixes

src/Psalm/Internal/Analyzer/Statements/Expression/Assignment/ArrayAssignmentAnalyzer.php

@@ -612,6 +612,7 @@ class ArrayAssignmentAnalyzer
                             $prop_count
                         );
                     } else if ($prop_count !== null) {
+                        assert($array_atomic_type_list !== null);
                         $array_atomic_type = new TKeyedArray(
                             array_fill(
                                 0,
@@ -640,6 +641,7 @@ class ArrayAssignmentAnalyzer
                             'parent_nodes' => $root_type->parent_nodes
                         ]);
                     } else {
+                        assert($array_atomic_type_list !== null);
                         $array_atomic_type = new TKeyedArray(
                             array_fill(
                                 0,
@@ -660,6 +662,7 @@ class ArrayAssignmentAnalyzer
                         $array_atomic_type_list
                     );
                 } else {
+                    assert($array_atomic_type_array !== null);
                     $array_atomic_type = new TNonEmptyArray(
                         $array_atomic_type_array
                     );
@@ -671,7 +674,12 @@ class ArrayAssignmentAnalyzer
             ?? ($array_atomic_type_list !== null
                 ? Type::getNonEmptyList($array_atomic_type_list)
                 : null
-            ) ?? new TNonEmptyArray($array_atomic_type_array);
+            ) ?? ($array_atomic_type_array !== null
+                ? new TNonEmptyArray($array_atomic_type_array)
+                : null
+            )
+        ;
+        assert($array_atomic_type !== null);
 
         $array_assignment_type = new Union([$array_atomic_type]);
 

src/Psalm/Internal/Provider/ReturnTypeProvider/ArrayMergeReturnTypeProvider.php

@@ -109,7 +109,10 @@ class ArrayMergeReturnTypeProvider implements FunctionReturnTypeProviderInterfac
                             } elseif (!$is_replace) {
                                 if ($unpacking_indefinite_number_of_args) {
                                     $added_inner_values = true;
-                                    $inner_value_types[] = $type;
+                                    $inner_value_types = array_merge(
+                                        $inner_value_types,
+                                        array_values($type->getAtomicTypes())
+                                    );
                                 } else {
                                     $generic_properties[] = $type;
                                 }

src/Psalm/Internal/Provider/ReturnTypeProvider/ArrayReverseReturnTypeProvider.php

@@ -45,7 +45,7 @@ class ArrayReverseReturnTypeProvider implements FunctionReturnTypeProviderInterf
         ? $array_atomic_type
         : null;
 
-        if (!$first_arg_array) {
+        if (!$first_arg_array || !$first_arg_type) {
             return Type::getArray();
         }
 

src/Psalm/Type/Atomic/TKeyedArray.php

@@ -341,6 +341,7 @@ class TKeyedArray extends Atomic
             return new TArray([$key_type, $value_type]);
         }
 
+        assert($key_types !== []);
         $key_type = TypeCombiner::combine($key_types);
 
         if ($this->fallback_params !== null) {