Summary

Define ElementScanner14 to visit type parameters; surprisingly, type parameters and not visited by the previously available scanners.

Problem

Surprising behavior in javax.lang.model utility classes. At least one scanner class with the new functionality was written as part of the javac implementation.

Solution

Add overrides for the methods visiting executables and types to visit type parameters, if present.

Specification

--- old/src/java.compiler/share/classes/javax/lang/model/util/ElementScanner14.java 2019-12-04 19:16:42.857000999 -0800
+++ new/src/java.compiler/share/classes/javax/lang/model/util/ElementScanner14.java 2019-12-04 19:16:42.601000999 -0800
@@ -121,6 +123,48 @@
     }

     /**
+     * {@inheritDoc}
+     *
+     * @implSpec This implementation scans the type parameters, if
+     * any, and then the enclosed elements.
+     * 
+     *
+     * @param e  {@inheritDoc}
+     * @param p  {@inheritDoc}
+     * @return the result of scanning
+     */
+    @Override
+    public R visitType(TypeElement e, P p) {
+        return scan(createScanningList(e, e.getEnclosedElements()), p);
+    }
+
+    /**
+     * {@inheritDoc}
+     *
+     * @implSpec This implementation first scans the type parameters, if any, and then
+     * the parameters.
+     *
+     * @param e  {@inheritDoc}
+     * @param p  {@inheritDoc}
+     * @return the result of scanning
+     */
+    public R visitExecutable(ExecutableElement e, P p) {
+        return scan(createScanningList(e, e.getParameters()), p);
+    }
+