The following test fails in the JDK18 CI:

jdk/javadoc/doclet/testDocTreeDiags/TestDocTreeDiags.java

----------System.out:(55/2013)----------
Running test testStdout
Starting subtest 0.1: exit
Passed: javadoc exited OK, as expected

src/p/C.java:3: warning: length: 15 mid: 7 >>>t s[e]nte<<<
 * First sentence. &quot; Second sentence.
          ^
Starting subtest 0.2: message-caret: src/p/C.java:3
Passed: src: 10 caret: 10

src/p/C.java:3: warning: length: 20 mid: 10 >>>d s[e]nte<<<
 * First sentence. &quot; Second sentence.
                                   ^
Starting subtest 0.3: message-caret: src/p/C.java:3
Passed: src: 35 caret: 35

src/p/C.java:4: warning: length: 16 mid: 8 >>>lan[g].St<<<
 * {@link java.lang.String first phrase; &quot; second phrase }
                  ^
Starting subtest 0.4: message-caret: src/p/C.java:4
Passed: src: 18 caret: 18

src/p/C.java:4: warning: length: 14 mid: 7 >>>t p[h]ras<<<
 * {@link java.lang.String first phrase; &quot; second phrase }
                                  ^
Starting subtest 0.5: message-caret: src/p/C.java:4
Passed: src: 34 caret: 34

src/p/C.java:4: warning: length: 16 mid: 8 >>>ond[ ]phr<<<
 * {@link java.lang.String first phrase; &quot; second phrase }
                                                       ^
Starting subtest 0.6: message-caret: src/p/C.java:4
Passed: src: 55 caret: 55

src/p/C.java:5: warning: length: 14 mid: 7 >>>d n[o]w .<<<
 * And now ... <!-- this is a comment --> and so it was.
        ^
Starting subtest 0.7: message-caret: src/p/C.java:5
Passed: src: 8 caret: 8

src/p/C.java:5: warning: length: 26 mid: 13 >>>is [a] co<<<
 * And now ... <!-- this is a comment --> and so it was.
                            ^
Starting subtest 0.8: message-caret: src/p/C.java:5
Passed: src: 28 caret: 28

src/p/C.java:5: warning: length: 15 mid: 7 >>> so[ ]it <<<
 * And now ... <!-- this is a comment --> and so it was.
                                                ^
Starting subtest 0.9: message-caret: src/p/C.java:5
Passed: src: 48 caret: 48

src/p/C.java:8: warning: use of default constructor, which does not provide a comment
public class C {
       ^
result: Failed. Execution failed: `main' threw exception: java.lang.IllegalArgumentException: detail pattern not found: src/p/C.java:8: warning: use of default constructor, which does not provide a comment