[GROOVY-10096] STC: accepts incorrect program with flow typing

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Duplicate
• Affects Version/s: 4.0.0-alpha-2, 3.0.8
• Fix Version/s: 4.0.5
• Component/s: Static compilation, Static Type Checker
• Assignee: Unassigned
• Reporter: Stefanos Chaliasos
• Created: 19/May/21 08:37
• Updated: 13/Aug/22 15:20
• Resolved: 11/Jul/22 20:34

Description

I have the following Groovy program.

@groovy.transform.TypeChecked
class Main {
  public static Bar buz(Foo bux) {
    (((true || bux instanceof Bar)) ?
      bux :
       new Bar())
  }
  public static void main(String[] args) {
    buz(new Foo()).bar()
  }
}

class Foo {
  public void foo() {}
}

class Bar extends Foo {
  public void bar() {}
}

Actual Behavior

The program does not compile, and I get the following error.

Caught: org.codehaus.groovy.runtime.typehandling.GroovyCastException: Cannot cast object 'Foo@2e1792e7' with class 'Foo' to class 'Bar'
org.codehaus.groovy.runtime.typehandling.GroovyCastException: Cannot cast object 'Foo@2e1792e7' with class 'Foo' to class 'Bar'
        at Main.buz(Main.groovy:6)
        at Main.main(Main.groovy:9)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

Expected Behavior

Compile-time error.

Affected Version

This programs have been tested with the compiler from the master (commit: e33e2849e247608c5e1826b76098d3a68d16bebf), 4.0.0-alpha-2, and 3.0.8.

Issue Links

• duplicates: GROOVY-7971 @CS flow typing incorrectly casting to map at runtime