checker/tests/nullness-stubfile/NullnessStubfileMerge.java

// warning: stubfile1.astub:(line 16,col 6): Package-private method notReal(String) not found in
// type java.lang.String
// warning: stubfile1.astub:(line 19,col 1): Type not found: java.lang.NotARealClass
// warning: stubfile1.astub:(line 21,col 1): Type not found: not.real.NotARealClassInNotRealPackage

import org.checkerframework.checker.nullness.qual.*;

/*
 * This test reads two stub files:
 * tests/nullness-stubfile/stubfile1.astub
 * tests/nullness-stubfile/stubfile2.astub
 *
 * The annotations on the methods are merged such that reading the two
 * stub files is equavlent to the following stubfile:
 *
public final class  String {
     public @Nullable String intern();
     public @NonNull String substring(@Nullable int beginIndex) @Nullable;
     String(@Nullable String arg0);
     void getChars(@Nullable int arg0, @NonNull int arg1, @NonNull char @NonNull [] arg2, @NonNull int arg3) @NonNull;
}
*/
public class NullnessStubfileMerge {
  @Nullable String nullString = null;
  @NonNull String nonNull = "Hello!";

  void method() {
    // below fails because of stub file overruling annotated JDK
    // :: error: (type.argument)
    java.util.List<@NonNull String> l;

    // :: error: (assignment)
    @NonNull String error1 = nonNull.intern();

    nonNull.substring('!');

    @NonNull String y = nonNull.substring('!');

    char[] nonNullChars = {'1', '1'};
    char[] nullChars = null;
    nonNull.getChars(1, 1, nonNullChars, 1);

    // :: error: (argument)
    nonNull.getChars(1, 1, nullChars, 1);
  }
}