<div dir="ltr"><div><div><div><div>OK, that's another edge case then.</div><br>> The use of raw type like <span style="font-family:monospace">Foo</span> "rawifies" all the methods in class Foo.<br><br></div>I can't help but think this is a weird default but I am sure there are excellent reasons why this solution was chosen, so I am not going to argue about it.<br></div>At least, this is a good nudge to make people write the right code since it's easy to work around :)<br><br></div>Thank you!<div><br></div></div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Tue, Jun 10, 2025 at 6:07 PM Archie Cobbs <<a href="mailto:archie.cobbs@gmail.com">archie.cobbs@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>Following up on what Maurizio said. There is an important difference between <span style="font-family:monospace">Foo</span> and <span style="font-family:monospace">Foo<?></span>. The use of raw type like <span style="font-family:monospace">Foo</span> "rawifies" all the methods in class Foo.</div><div><br></div><div>Here's a simpler reproducer:</div><div><br></div><div style="margin-left:40px"><span style="font-family:monospace">import java.net.http.HttpResponse;<br>import java.util.Optional;<br>import javax.net.ssl.SSLSession;<br><br>public class Main2 {<br> void m1(HttpResponse r) {<br> Optional<SSLSession> s = r.sslSession(); // unchecked warning here<br> }<br> void m2(HttpResponse<?> r) {<br> Optional<SSLSession> s = r.sslSession(); // no warning here<br> }<br>}<br></span></div><div><br></div><div>See also <a href="https://stackoverflow.com/a/11007894/263801" target="_blank">this stackoverflow answer</a>.</div><div><br></div><div>-Archie</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Jun 10, 2025 at 10:51 AM Jean-Noël Rouvignac <<a href="mailto:jean-noel.rouvignac@pingidentity.com" target="_blank">jean-noel.rouvignac@pingidentity.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>Hello,</div><div><br></div><div>When doing refactorings to take advantage of newer Java features, I hit a new and weird edge case. I trimmed down the code several times, and ended up with the following tiny reproducer, and I don't understand what javac is complaining about even with javac 24:<br><div><div><br></div><div>(Note: unlike the original code, this reproducer is very contrived,
so there's no need to make comments on how bad it is: I fully agree)</div></div><br>```java<br>1 import java.util.ArrayList;<br>import java.util.List;<br>import java.util.stream.Collectors;<br><br>public class Main {<br> private static final class Child<T> {<br> public List<String> getValues() {<br> return new ArrayList<>();<br> }<br> }<br><br> @SuppressWarnings("unchecked")<br> private static String getString1(Child c) {<br> // Compilation error:<br> // Main.java:16: error: incompatible types: Object cannot be converted to String<br> return c.getValues().stream().collect(Collectors.joining());<br> }<br><br> private static String getString2(Child c) {<br> // Compilation error:<br> // Main.java:27: warning: [unchecked] unchecked conversion<br> // List<String> values = c.getValues();<br> // ^<br> // required: List<String><br> // found: List<br> //1 warning<br> List<String> values = c.getValues();<br> return values.stream().collect(Collectors.joining());<br> }<br>}<br>```<br><br>It turns out IntelliJ is a bit more eloquent than javac, and when hovering over the warning on `c.getValues()` at the line with `List<String> values = c.getValues();`, it reports the following:<br><br>> Unchecked assignment: 'java.util.List' to
'java.util.List<java.lang.String>'. Reason: 'c' has raw type, so
result of getValues is erased <br><br></div><div>Is it possible that javac is doing early type erasure when analysing this code, erasing a bit too much? Even if the code uses `Child` without type argument, I would expect the return type of `getValues()` to be well defined as `List<String>`?<br><br></div><div>What do you think?<br></div><div>I am sure there is some rational explanation that I missed for this behaviour. I could not find a JBS issue showing the same case as here.</div><div><br></div><div>Thank you,</div><div>Jean-Noël Rouvignac</div></div>
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