Bug 475018

Description Lukas Eder 2015-08-15 04:20:20 EDT

Consider the following code:

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import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;


class Person {
    int id;
    String name;

    void x() {
        List<Person> people = Collections.emptyList();
        Map<Integer, List<String>> namesPerId =
        people.stream()
              .collect(Collectors.groupingBy(
                  p -> p.id,
                  Collectors.mapping(p -> p.name, Collectors.toList()
              ));
              
        System.out.println("test");
    }
}

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The call to Collectors.mapping() is missing a closing parenthesis. This, however is not reported by the Eclipse compiler, which reports a very generic error on "p -> p.name":

Syntax error on token(s), misplaced construct(s)

Note that when leaving out the "System.out.println("test") call ...

--------------------------------------------------------------------
    void x() {
        List<Person> people = Collections.emptyList();
        Map<Integer, List<String>> namesPerId =
        people.stream()
              .collect(Collectors.groupingBy(
                  p -> p.id,
                  Collectors.mapping(p -> p.name, Collectors.toList()
              ));
    }
--------------------------------------------------------------------

... the compiler now reports two errors. One on "p.name" (1), and one on the missing parenthesis (2):

1) Syntax error on tokens, LambdaBody expected instead
2) Syntax error, insert ")" to complete Expression