8334757: AssertionError: Missing type variable in where clause

Reviewed-by: jlahoda, vromero

src/jdk.compiler/share/classes/com/sun/tools/javac/util/RichDiagnosticFormatter.java

@@ -184,6 +184,9 @@ protected void preprocessArgument(Object arg) {
         if (arg instanceof Type type) {
             preprocessType(type);
         }
+        else if (arg instanceof JCDiagnostic.AnnotatedType type) {
+            preprocessType(type.type());
+        }
         else if (arg instanceof Symbol symbol) {
             preprocessSymbol(symbol);
         }

test/langtools/tools/javac/annotations/typeAnnotations/failures/CantAnnotateClassWithTypeVariable.java

@@ -0,0 +1,19 @@
+/*
+ * @test /nodynamiccopyright/
+ * @bug 8334757
+ * @compile/fail/ref=CantAnnotateClassWithTypeVariable.out -XDrawDiagnostics CantAnnotateClassWithTypeVariable.java
+ */
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Target;
+
+public class CantAnnotateClassWithTypeVariable {
+  @Target(ElementType.TYPE_USE)
+  @interface TA {}
+
+  static class A {
+    static class B<T> {}
+  }
+
+  <T> @TA A.B<T> f() {}
+}

test/langtools/tools/javac/annotations/typeAnnotations/failures/CantAnnotateClassWithTypeVariable.out

@@ -0,0 +1,2 @@
+CantAnnotateClassWithTypeVariable.java:18:14: compiler.err.type.annotation.inadmissible: (compiler.misc.type.annotation.1: @CantAnnotateClassWithTypeVariable.TA), CantAnnotateClassWithTypeVariable.A, @CantAnnotateClassWithTypeVariable.TA CantAnnotateClassWithTypeVariable.A.B<T>
+1 error