[GROOVY-11335] STC: for loop element type inference with multiple instanceof

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 5.0.0-alpha-7, 4.0.20, 3.0.22
• Component/s: Static Type Checker

Language

groovy

• Assignee: Eric Milles
• Reporter: Eric Milles
• Created: 08/Mar/24 17:47
• Updated: 24/Mar/24 23:12
• Resolved: 09/Mar/24 01:13

Description

Consider the following:

@groovy.transform.TypeChecked
void test(obj) {
  if (obj instanceof Collection) {
    if (obj instanceof Serializable) {
      for (item in obj) {
        println item
      }
    }
  }
}

The inferred type of "obj" is (Collection & Serializable). The loop element check fails with:

java.lang.UnsupportedOperationException
	at org.codehaus.groovy.transform.stc.UnionTypeClassNode.getComponentType(UnionTypeClassNode.java:232)
	at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.inferLoopElementType(StaticTypeCheckingVisitor.java:2042)
	at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.visitForLoop(StaticTypeCheckingVisitor.java:2008)
	at org.codehaus.groovy.ast.stmt.ForStatement.visit(ForStatement.java:47)

Issue Links

• is related to: GROOVY-11305 STC: support for-each or for-in loop for implicitly-Iterable type