⚡ Sangsakala Proxy 🏠 Home
Skip to content

java/local-shadows-field: a local declared inside a lambda or anonymous class body is not reported #22969

Open

Description

@MarkLee131

Description of the issue

The query reports the local String[] arr in ShadowSeed.getArr(), which has the same name as the field the method reads as this.arr. Declare the same local inside a lambda in that method (ShadowVariant) or inside an anonymous class (ShadowControl) and nothing is reported, though it still shadows the field and the method still reads this.arr.

Probably the shadows predicate in Shadowing.qll: it requires the local's callable to be declared by the class that declares the field (method.getDeclaringType() = c). Inside a lambda the callable is the lambda's own method, and inside an anonymous class it's that class's method.

Query: java/local-shadows-field (codeql/java-queries 1.1.10)

CodeQL CLI: 2.27.2

Code samples

seed/ShadowSeed.java:

public class ShadowSeed {
    String[] arr;
    String[] getArr() {
        String[] arr;                      // shadows the field; the query fires here
        return this.arr;
    }
}

variant/ShadowVariant.java:

public class ShadowVariant {
    String[] arr;
    String[] getArr() {
        Runnable r = () -> {
            String[] arr;                  // the same local inside a lambda body; not reported
        };
        r.run();
        return this.arr;
    }
}

control/ShadowControl.java:

public class ShadowControl {
    String[] arr;
    String[] getArr() {
        Runnable r = new Runnable() {
            public void run() {
                String[] arr;              // inside an anonymous class; not reported either
            }
        };
        r.run();
        return this.arr;
    }
}

How to reproduce

codeql database create db --language=java --build-mode=none \
    --source-root=<one directory> --overwrite
codeql database analyze db \
    codeql/java-queries:codeql-suites/java-security-and-quality.qls \
    --format=csv --output=out.csv
# one database per directory

Expected result

"Potentially confusing name: method ... also refers to field arr (as this.arr)" on the local in ShadowVariant.java (line 5) and in ShadowControl.java (line 6), as on ShadowSeed.java (line 4).

Output of the commands above:

### CodeQL 2.27.2  query: java/local-shadows-field
### suite: java-security-and-quality.qls, --build-mode=none, per-file isolated databases
### extraction JDK: openjdk version "21.0.11" 2026-04-21 LTS

--- SEED -- expected: query fires (seed/)
"Possible confusion of local and field","A method in which a variable is declared with the same name as a fiel

--- VARIANT -- expected: query fires, actual: not reported (the bug) (variant/)
    (query reported nothing)

--- CONTROL -- the same construct in an anonymous class, expected: query fires (control/)
    (query reported nothing)

Activity

  1. sam-robson commented on Nov 3, 2026

    @sam-robson
    Contributor

    Hi @MarkLee131, thanks for the detailed report. We'll take a look into this and follow up.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Metadata

Metadata

Assignees

No one assigned

    Labels

    Type

    No type

    Projects

    No projects

      Milestone

      No milestone

      Relationships

      None yet

      Development

      No branches or pull requests

      Issue actions