[GROOVY-9769] STC: UnionTypeClassNode created for simple instanceof scenarios

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 3.0.7, 4.0.0-alpha-2, 2.5.15
• Assignee: Eric Milles
• Reporter: Eric Milles
• Created: 03/Oct/20 16:05
• Updated: 23/Jan/24 17:15
• Resolved: 06/Oct/20 11:57

Description

Consider the following:

interface A {
  def foo() {}
}
interface B extends A {
  def bar() {}
}
@groovy.transform.CompileStatic
void test(A a) {
  if (a instanceof B) {
    a.foo()
    a.bar()
  }
}

Variable expression "a" infers to "<UnionType:A+B>" due to instanceof screening. Since B extends A, a simple ClassNode for B should be sufficient.

The union types are harder to deal with for consumers. This is a variant of GROOVY-7333.

Issue Links

• relates to: GROOVY-11290 STC: multiple instanceof checks produce different results
• relates to: GROOVY-11137 Improve support for union and intersection types