doc-comment tests: add counterexamples for issue186

Issue 186 relates to symbols that are not documented.  Add tests for
symbols that are documented in a file of the same structure.

t/300-doc-comments.t

@@ -170,4 +170,23 @@ run_produces_ok('No warnings on macro, #186',
     [ ],
     MUST_SUCCEED);  # warnings appear on stderr, failing the MUST_SUCCEED checks
 
+# #186 counterexamples
+run_produces_ok('ident query (existent, documented as function), #186 counterexample',
+    [$tenv->query_py, qw(v5.4 ident i186c_fn1 C)],
+    [
+        qr{^Documented in:},
+        {doc => qr{\bissue186-counterexamples\.c.+\b5\b}},
+    ],
+    MUST_SUCCEED);
+
+run_produces_ok('ident query (existent, documented as macro), #186 counterexample',
+    [$tenv->query_py, qw(v5.4 ident i186c_fn2 C)],
+    [
+        qr{^Documented in:},
+        {doc => qr{\bissue186-counterexamples\.c.+\b20\b}},
+    ],
+    MUST_SUCCEED);
+
+#########################################################################
+
 done_testing;

t/tree/issue186-counterexamples.c

@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: CC0-1.0
+// This file is the situation of #186, but with documentation.
+
+#ifdef SOMETHING
+/**
+ * i186c_fn1 - do something
+ */
+static int i186c_fn1(struct platform_device *pdev)
+{
+}
+#else
+#define i186c_fn1	NULL
+#endif
+
+#ifdef SOMETHING
+static int i186c_fn2(struct platform_device *pdev)
+{
+}
+#else
+/**
+ * i186c_fn2 - do something
+ */
+#define i186c_fn2	NULL
+#endif