If the test jdk/javadoc/doclet/testValueTag/TestValueTagInModule.java is run on its own, it fails with:

/home/erik/hg/jdk/open/test/langtools/tools/lib/toolbox/JavacTask.java:46: error: package com.sun.tools.javac.api is not visible
import com.sun.tools.javac.api.JavacTaskImpl;
                          ^
  (package com.sun.tools.javac.api is declared in module jdk.compiler, which does not export it to the unnamed module)
/home/erik/hg/jdk/open/test/langtools/tools/lib/toolbox/JavacTask.java:47: error: package com.sun.tools.javac.api is not visible
import com.sun.tools.javac.api.JavacTool;
                          ^
  (package com.sun.tools.javac.api is declared in module jdk.compiler, which does not export it to the unnamed module)
Note: Some input files use unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
2 errors

This is because a test lib it uses needs the jdk.compiler module to compile. The reason this works in langtools/:tier1 is that this test is rarely the first test to use this lib, so the lib is already compiled when it's time for this test.

I discovered this while experimenting with concurrency settings for testing and this test started failing with higher concurrency.

Suggested fix:

diff -r fad3614d1f0f test/langtools/jdk/javadoc/doclet/testValueTag/TestValueTagInModule.java
--- a/test/langtools/jdk/javadoc/doclet/testValueTag/TestValueTagInModule.java
+++ b/test/langtools/jdk/javadoc/doclet/testValueTag/TestValueTagInModule.java
@@ -27,6 +27,8 @@
  * @summary {@value} should be permitted in module documentation
  * @library /tools/lib ../lib
  * @modules jdk.javadoc/jdk.javadoc.internal.tool
+ * jdk.compiler/com.sun.tools.javac.api
+ * jdk.compiler/com.sun.tools.javac.main
  * @build JavadocTester
  * @run main TestValueTagInModule
  */