Class PHPStan\Type\UnionType

Returns all class names referenced anywhere in this type, recursively (including generic arguments, callable signatures, etc.).

Returns class names of the object types this type directly represents. Unlike getReferencedClasses(), excludes classes in generic arguments, etc.

Only ConstantArrayType instances (array shapes with known keys).

Unlike isSuperTypeOf(), accepts() takes into account PHP's implicit type coercion. With $strictTypes = false, int is accepted by float, and Stringable objects are accepted by string.

"Does every value of $type belong to $this type?" Preferable to instanceof checks because it correctly handles union types, intersection types, and all other composite types.

Answers "is this compound type a subtype of $otherType?" from the compound type's perspective. Called by simple types when they encounter a CompoundType argument in their isSuperTypeOf() method. The compound type decomposes itself and calls $otherType->isSuperTypeOf() for each component. For example, UnionType(string|int)::isSubTypeOf(MixedType) asks MixedType whether it is a supertype of string and int separately, then combines with extremeIdentity (all must pass).

Answers "is this compound type accepted by $acceptingType?" from the compound type's perspective. Called by simple types when they encounter a CompoundType argument in their accepts() method. The compound type decomposes itself and calls $acceptingType->accepts() for each component. For example, UnionType(string|int)::isAcceptedBy(StringType) asks StringType to accept string and int separately, then combines results with extremeIdentity (all must pass).

Returns actual template type for a given object. Example: @-template T class Foo {} // $fooType is Foo $t = $fooType->getTemplateType(Foo::class, 'T'); $t->isInteger(); // yes Returns ErrorType in case of a missing type.

Unlike getInstanceProperty(), this defers template type resolution. Use getInstanceProperty() in most rule implementations.

Unlike getMethod(), this defers template type and static type resolution. Use getMethod() in most rule implementations.

Returns the count of elements as a Type (typically IntegerRangeType).

Works for both arrays and Traversable objects.

An oversized array is a constant array shape that grew too large to track precisely and was degraded to a generic array type.

A list is an array with sequential integer keys starting from 0 with no gaps.

Non-falsy string is a non-empty string that is also not '0'. Stricter subset of non-empty-string.

A literal-string is a string composed entirely from string literals in the source code (not from user input). Used for SQL injection prevention.

Returns the object type for a class-string or literal class name string. For non-class-string types, returns ErrorType.

Like getClassStringObjectType(), but also returns object types as-is. Used for $classOrObject::method() where the left side can be either.

Whether accessing a non-existent offset is safe (won't cause errors). Unlike isOffsetAccessible() which checks if offset access is supported at all.

May add a new key. When $offsetType is null, appends (like $a[] = $value).

Unlike setOffsetValueType(), assumes the key already exists. Preserves the array shape and list type.

Models array_keys($array, $searchValue, $strict).

Models array_keys($array).

Models array_values($array).

Models array_chunk($array, $length, $preserveKeys).

Models array_fill_keys($keys, $value).

Models array_flip($array).

Models array_intersect_key($array, ...$otherArrays).

Models array_pop() effect on the array.

Models array_reverse($array, $preserveKeys).

Models array_search($needle, $array, $strict).

Models array_shift() effect on the array.

Models shuffle() effect on the array. Result is always a list.

Models array_slice($array, $offset, $length, $preserveKeys).

Models array_splice() effect on the array (the modified array, not the removed portion).

Returns the single enum case this type represents, or null if not exactly one case.

Is Type of a known constant value? Includes literal strings, integers, floats, true, false, null, and array shapes. Unlike isConstantScalarValue(), this also returns yes for constant array types (array shapes with known keys and values). Use this when you need to detect any constant value including arrays.

Is Type of a known constant scalar value? Includes literal strings, integers, floats, true, false, and null. Unlike isConstantValue(), this does NOT return yes for array shapes. Use this when you specifically need scalar constants only.

Type narrowing methods for comparison operators. For example, for ConstantIntegerType(5), getSmallerType() returns int<min, 4>.

Compares this compound type against $otherType using greater-than semantics. Used for comparison operators (>). Each compound type decomposes the comparison across its members (e.g., IntegerRangeType checks whether all values in the range are greater than the other type).

Compares this compound type against $otherType using greater-than-or-equal semantics. Used for comparison operators (>=). Same decomposition strategy as isGreaterThan().

Models the (bool) cast.

Models numeric coercion for arithmetic operators.

Models abs().

Models the (string) cast.

Models the (int) cast.

Models the (float) cast.

Models the (array) cast.

Models PHP's implicit array key coercion: floats truncated to int, booleans become 0/1, null becomes '', numeric strings become int.

Returns how this type might change when passed to a typed parameter or assigned to a typed property. With $strictTypes = true: int widens to int|float (since int is accepted by float parameters in strict mode). With $strictTypes = false: additional coercions apply, e.g. Stringable objects are accepted by string parameters. Used internally to determine what types a value might be coerced to when checking parameter acceptance.

Infers the real types of TemplateTypes found in $this, based on the received Type. E.g. if $this is array<T> and $receivedType is array, infers T = int.

Returns the template types referenced by this Type, recursively. The return value is a list of TemplateTypeReferences, who contain the referenced template type as well as the variance position in which it was found. For example, calling this on array<Foo<T>,Bar> (with T a template type) will return one TemplateTypeReference for the type T.

Returns a new instance with all inner types mapped through $cb. Returns the same instance if inner types did not change. Not used directly — use TypeTraverser::map() instead.

Like traverse(), but walks two types simultaneously. Not used directly — use SimultaneousTypeTraverser::map() instead.

Models the ** operator.

Returns a list of finite values this type can take. Examples: - for bool: [true, false]

• for int<0, 3>: [0, 1, 2, 3]
• for enums: list of enum cases
• for scalars: the scalar itself For infinite types it returns an empty array.

Performance optimization to skip template resolution when no templates are present.