Java8: method reference to a non-static method fails to compile

NOT REPRODUCIBLE

In this code sample:

return map.entrySet().stream()
			.collect(Collectors.toMap(
				Map.Entry::getKey,
				e -> e.getValue().getAverage()
			));

the Collectors.toMap() takes a "Map.Entry::getKey" method reference as input argument. However, the getKey method is not static.

Wrapping it by Clover's lambdaInc() method leads to a compilation error like this:

    [javac]   symbol:   method lambdaInc(int,Map.Entry::getKey,int)
    [javac]   location: class __CLR4_0_22ci2cii4lxhoaj
    [javac]  Foo.java:33: error: invalid method reference
    [javac] 					__CLR4_0_22ci2cii4lxhoaj.lambdaInc(3045,Map.Entry::getKey,3046),
    [javac] 					                                           ^
    [javac]   non-static method getKey() cannot be referenced from a static context
    [javac]   where K is a type-variable:
    [javac]     K extends Object declared in interface Entry

Possible workarounds ??

1) Disable instrumentation of expression-like lambda functions (method references are treated as expression-like lambda) - use instrumentLambda="block" or "none".

2) Wrap such method reference with ///CLOVER:OFF and ///CLOVER:ON keywords, e.g.:

return map.entrySet().stream()
			.collect(Collectors.toMap(
///CLOVER:OFF
				Map.Entry::getKey,
///CLOVER:ON
				e -> e.getValue().getAverage()
			));

3) Use a variable with a non-static method reference or change to a lambda expression.

return map.entrySet().stream()
			.collect(Collectors.toMap(
				e -> e.getKey(), // unfortunately IDEA suggests to change it back
				e -> e.getValue().getAverage()
			));