* value is undefined.
     *
     * @return the location of the problem, never {@code null}
     */
    @Nonnull
    String getLocation();

    /**
     * Gets the exception that caused this problem (if any).
     *
     * @return the exception that caused this problem or {@code null} if not applicable
     */
    @Nullable

                @Override
                public Path getPath() {
                    return Paths.get("test-pom.xml");
                }

                @Override
                public String getLocation() {
                    return "test-pom.xml";
                }

                @Override
                public InputStream openStream() throws IOException {
                    return null;

                    .map(MojoExecution::getPlugin)
                    .filter(p -> p.getLocation("version") != null
                            && p.getLocation("version").getSource() != null
                            && defaulModelId.equals(
                                    p.getLocation("version").getSource().getModelId()))
                    .distinct()

            @Override
            public InputStream openStream() throws IOException {
                return Files.newInputStream(actual);
            }

            @Override
            public String getLocation() {
                return actual.toString();
            }

            @Override
            public Source resolve(String relative) {
                return Sources.buildSource(actual.resolve(relative));

                slf4jLogger.warn("{} @ {}", problem.getMessage(), problem.getLocation());
            }

            slf4jLogger.warn("");
        }
    }

    private Object getLocation(Source source, File defaultLocation) {
        if (source != null) {
            return source.getLocation();
        }
        return defaultLocation;
    }

            }
            trackingData.add(indent + plugin.getGroupId() + ":" + plugin.getArtifactId() + ":" + plugin.getVersion());
            indent.append("  ");

            InputLocation location = plugin.getLocation("");
            if (location != null && location.getSource() != null) {
                trackingData.add(indent + location.getSource().getModelId() + " (implicit)");
                indent.append("  ");
            }

        </field>
      </fields>
      <codeSegments>
        <codeSegment>
          <version>1.2.0+</version>
          <code>
    @Override
    public String toString() {
        return getLocation();
    }
          </code>
        </codeSegment>
      </codeSegments>
    </class>
  </classes>

        Source src = mock(Source.class);
        IOException ioException = new IOException("MESSAGE");
        doThrow(ioException).when(src).getInputStream();
        doReturn("LOCATION").when(src).getLocation();

        ToolchainsBuildingRequest request = new DefaultToolchainsBuildingRequest();
        request.setGlobalToolchainsSource(src);

        try {
            toolchainBuilder.build(request);

        for (CoreExtension coreExtension : coreExtensions) {
            String ga = coreExtension.getGroupId() + ":" + coreExtension.getArtifactId();
            InputLocation location = coreExtension.getLocation("");
            gasLocations.computeIfAbsent(ga, k -> new ArrayList<>()).add(location);
            // TODO: metaversions could be extensible enum with these two values out of the box

                for (BuilderProblem problem :
                        toolchainsResult.getProblems().problems().toList()) {
                    context.logger.warn(problem.getMessage() + " @ " + problem.getLocation());
                }
            }

            context.logger.info("");
        }
    }

    @Override