Scott Murphy Heiberg created GROOVY-12756:
---------------------------------------------
Summary: STC: since GROOVY-12714 a value that is not a Class
cannot be assigned to a parameterized Class variable
Key: GROOVY-12756
URL: https://issues.apache.org/jira/browse/GROOVY-12756
Project: Groovy
Issue Type: Bug
Components: Static Type Checker
Affects Versions: 6.0.1, 7.0.0-alpha-1
Reporter: Scott Murphy Heiberg
Anything can be assigned to a variable of type {{Class}}, {{String}} or
{{Boolean}}: the value is converted at run time, so {{Class c =
'java.lang.String'}} loads the class. That still compiles for a raw {{Class}}.
Since GROOVY-12714 (GROOVY_6_0_X and master) static type checking rejects it
when the variable's type has a type argument, even {{Class<?>}}:
{code:groovy}
import java.lang.reflect.ParameterizedType
import java.lang.reflect.Type
@groovy.transform.CompileStatic
abstract class Editor<T> {
final Class<T> targetType
Editor() {
Type[] types = ((ParameterizedType)
getClass().genericSuperclass).actualTypeArguments
targetType = types[0]
}
}
@groovy.transform.CompileStatic
void test(Type type, Object object) {
Class raw = type // compiles
Class<?> any = type // error
Class<String> string = 'java.lang.String' // error
Class<? extends Number> number = object // error
}
{code}
{noformat}
[Static type checking] - Incompatible generic argument types. Cannot assign
java.lang.reflect.Type to: java.lang.Class<T>
[Static type checking] - Incompatible generic argument types. Cannot assign
java.lang.reflect.Type to: java.lang.Class<?>
[Static type checking] - Incompatible generic argument types. Cannot assign
java.lang.String to: java.lang.Class<java.lang.String>
[Static type checking] - Incompatible generic argument types. Cannot assign
java.lang.Object to: java.lang.Class<? extends java.lang.Number>
{noformat}
All of these compiled on GROOVY_6_0_X before GROOVY-12714 (a5d10dd198). The
first is {{AbstractStructuredBindingEditor}} in Grails, which no longer
compiles against GROOVY_6_0_X.
For an assignment to a {{Class}}, {{String}} or {{Boolean}} variable,
{{getResultType}} returned the variable's type. GROOVY-12714 made it keep the
type of the value when the variable is a parameterized {{Class}}, so that
{{Class<?>}} is no longer accepted for {{Class<? extends CharSequence>}}. That
is right when the value is a {{Class}}. When it is not, there are no type
arguments to compare, and {{checkTypeGenerics}} reports the value's type as an
incompatible generic argument.
The value's type should be kept only when it is a {{Class}}.
--
This message was sent by Atlassian Jira
(v10.3.26#10030026)
