[GROOVY-10720] Resolving wrong overloaded method?

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 4.0.5, 2.5.19, 3.0.13
• Component/s: Static Type Checker
• Assignee: Eric Milles
• Reporter: Thodoris Sotiropoulos
• Created: 08/Aug/22 07:44
• Updated: 29/May/23 15:39
• Resolved: 08/Aug/22 16:08

Description

I have the following program

import java.util.Arrays;

class Test {
    void test() {
      Double[] x = null;
      var y = Arrays.stream(x).map(d -> "fda").findFirst();
    }
}

Actual behavior

org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
test.groovy: 7: [Static type checking] - Cannot return value of type java.lang.String for lambda expecting double
 @ line 7, column 41.
   y = Arrays.stream(x).map(d -> "fda").fin
                                 ^

1 error

Expected behavior

Compile successfully

This issue stems from the fact that there are two relevant overloaded `stream()` methods in the class `java.utils.Arrays`. See the corresponding signatures below:

• static DoubleStream stream​(double[] array)
• static <T> Stream<T> stream​(T[] array)

So the compiler chooses to call the first method, because it thinks that the first method is more specific than the second one. I don't know if this is a bug or a feature. FYI, javac resolves the second method.

Issue Links

• relates to: GROOVY-11053 Method ambiguity error when having methods with primitive arrays and varargs