False positive compilation of a method reference with type parameters

Ешкеев Никита kastolom at gmail.com
Mon Jan 6 21:07:56 UTC 2020


I expect the compilation of the following code should fail, but the
compilation is successful:

public class Demo {
    static <T> void cons(T c) { System.out.println(c.getClass()); }
    static void cons(int var) { System.out.println("int"); }

    public static void main(String[] args) {
        java.util.function.IntConsumer cons1 = Demo::<String>cons; // <--
the type parameter is ignored
        java.util.function.Consumer<Integer> cons2 = Demo::<String>cons; //
<-- wrong type parameter for the consumer

$ javac Demo.java ; java Demo

I checked for both java-8
$ java -version
openjdk version "1.8.0_232"
OpenJDK Runtime Environment (build 1.8.0_232-b09)
OpenJDK 64-Bit Server VM (build 25.232-b09, mixed mode)

and java-11:
$ java -version
openjdk version "11.0.5" 2019-10-15
OpenJDK Runtime Environment (build 11.0.5+10)
OpenJDK 64-Bit Server VM (build 11.0.5+10, mixed mode)

My OS: Arch Linux funcs 5.4.8-arch1-1 #1 SMP PREEMPT Sat, 04 Jan 2020
23:46:18 +0000 x86_64 GNU/Linux

Best Regards,
Eshkeev Nikita

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