Add test case for false positive

But this commit doesn't actually fix the problem.

The problem is that the try statements aren't handled yet and simple
continue with the next block, which in the case of a `while True` loop
creates an infinite loop. Thus the rule triggers on any statements after
the while loop, but this is incorrect.

crates/ruff/resources/test/fixtures/control-flow-graph/while.py

@@ -98,3 +98,24 @@ def func():
     while True:
         if True:
             break
+
+'''
+TODO: because `try` statements aren't handled this triggers a false positive as
+the last statement is reached, but the rules thinks it isn't (it doesn't
+see/process the break statement).
+
+# Test case found in the Bokeh repository that trigger a false positive.
+def bokeh2(self, host: str = DEFAULT_HOST, port: int = DEFAULT_PORT) -> None:
+    self.stop_serving = False
+    while True:
+        try:
+            self.server = HTTPServer((host, port), HtmlOnlyHandler)
+            self.host = host
+            self.port = port
+            break
+        except OSError:
+            log.debug(f"port {port} is in use, trying to next one")
+            port += 1
+
+    self.thread = threading.Thread(target=self._run_web_server)
+'''

crates/ruff/resources/test/fixtures/ruff/RUF014.py

@@ -162,3 +162,24 @@ def bokeh1(self, obj: BytesRep) -> bytes:
             self.error(f"can't resolve buffer '{id}'")
 
     return buffer.data
+
+'''
+TODO: because `try` statements aren't handled this triggers a false positive as
+the last statement is reached, but the rules thinks it isn't (it doesn't
+see/process the break statement).
+
+# Test case found in the Bokeh repository that trigger a false positive.
+def bokeh2(self, host: str = DEFAULT_HOST, port: int = DEFAULT_PORT) -> None:
+    self.stop_serving = False
+    while True:
+        try:
+            self.server = HTTPServer((host, port), HtmlOnlyHandler)
+            self.host = host
+            self.port = port
+            break
+        except OSError:
+            log.debug(f"port {port} is in use, trying to next one")
+            port += 1
+
+    self.thread = threading.Thread(target=self._run_web_server)
+'''

crates/ruff/src/rules/ruff/rules/unreachable.rs

@@ -923,7 +923,12 @@ mod tests {
             .body;
 
         for (i, stmts) in stmts.into_iter().enumerate() {
-            let func = stmts.function_def_stmt().expect("statement not a function");
+            let Some(func) = stmts.function_def_stmt() else {
+                // Shouldn't happen, but if it does it helps with debugging.
+                #[allow(clippy::print_stderr)]
+                eprintln!("unexpected statement kind, ignoring");
+                continue;
+            };
 
             let got = BasicBlocks::from(&*func.body);
             // Basic sanity checks.