Fix #9824 by not warning about unused matches in pattern quotes.

compiler/rename/RnPat.lhs

@@ -203,6 +203,9 @@ matchNameMaker ctxt = LamMk report_unused
     -- i.e. when you type 'x <- e' at the GHCi prompt
     report_unused = case ctxt of
                       StmtCtxt GhciStmtCtxt -> False
+                      -- also, don't warn in pattern quotes, as there
+                      -- is no RHS where the variables can be used!
+                      ThPatQuote            -> False
                       _                     -> True
 
 rnHsSigCps :: HsWithBndrs RdrName (LHsType RdrName)

testsuite/tests/th/all.T

@@ -346,4 +346,4 @@ test('T9209', normal, compile_fail, ['-v0'])
 test('T7484', normal, compile_fail, ['-v0'])
 test('T1476', normal, compile, ['-v0'])
 test('T1476b', normal, compile_fail, ['-v0'])
-test('T9824', expect_broken(9824), compile, ['-v0'])
+test('T9824', normal, compile, ['-v0'])