Revert "Fix array_count_values key type for general string input"

This reverts commit 4c7aa46.

Author: ondrejmirtes

CLAUDE.md

@@ -323,10 +323,6 @@ Many built-in PHP functions need `DynamicFunctionReturnTypeExtension` implementa
 - Extensions live in `src/Type/Php/` and are registered in `conf/services.neon`
 - Each reads the argument types from `Scope::getType()` and returns a more precise `Type`
 
-### toArrayKey() and numeric string coercion
-
-`Type::toArrayKey()` converts a value type to its array key representation. `StringType::toArrayKey()` returns `string`, but PHP casts numeric strings (like `'123'`) to integer keys. `ConstantStringType::toArrayKey()` correctly handles this (e.g. `'1'` → `int(1)`), and `AccessoryNumericStringType::toArrayKey()` returns `int|numeric-string`. However, a general `string` where `isNumericString()` returns `maybe` needs special handling in extensions that create arrays from values — the key type should be `int|string` (array-key), not just `string`. This applies to `array_count_values`, `array_flip`, and similar functions where input values become output keys.
-
 ### Function signature corrections (`src/Reflection/SignatureMap/`)
 
 PHPStan maintains its own signature map for built-in PHP functions in `functionMap.php` and delta files. Fixes involve:

src/Type/Php/ArrayCountValuesDynamicReturnTypeExtension.php

@@ -54,16 +54,8 @@ public function getTypeFromFunctionCall(
 				continue;
 			}
 
-			$keyType = $itemType->toArrayKey();
-
-			// PHP casts numeric strings to integer keys, so a general string
-			// that might be numeric should produce int|string keys
-			if ($itemType->isString()->yes() && $itemType->isNumericString()->maybe()) {
-				$keyType = TypeCombinator::union($keyType, new IntegerType());
-			}
-
 			$outputTypes[] = new IntersectionType([
-				new ArrayType($keyType, IntegerRangeType::fromInterval(1, null)),
+				new ArrayType($itemType->toArrayKey(), IntegerRangeType::fromInterval(1, null)),
 				new NonEmptyArrayType(),
 			]);
 		}

tests/PHPStan/Analyser/nsrt/array-count-values.php

@@ -25,7 +25,7 @@ function returnsStringOrObjectArray(): array
 }
 
 // Objects are ignored by array_count_values, with a warning emitted.
-assertType('non-empty-array<int|string, int<1, max>>', array_count_values(returnsStringOrObjectArray()));
+assertType('non-empty-array<string, int<1, max>>', array_count_values(returnsStringOrObjectArray()));
 
 class StringableObject
 {