driver: Include debug level in the recompilation check hash

Fixes #17586.

compiler/iface/FlagChecker.hs

@@ -61,7 +61,7 @@ fingerprintDynFlags dflags@DynFlags{..} this_mod nameio =
         ticky =
           map (`gopt` dflags) [Opt_Ticky, Opt_Ticky_Allocd, Opt_Ticky_LNE, Opt_Ticky_Dyn_Thunk]
 
-        flags = (mainis, safeHs, lang, cpp, paths, prof, ticky)
+        flags = ((mainis, safeHs, lang, cpp), (paths, prof, ticky, debugLevel))
 
     in -- pprTrace "flags" (ppr flags) $
        computeFingerprint nameio flags

testsuite/tests/driver/T17586/Makefile

+TOP=../..
+include $(TOP)/mk/boilerplate.mk
+include $(TOP)/mk/test.mk
+
+T17586:
+	"$(TEST_HC)" $(TEST_HC_OPTS) -o T17586 ./T17586.hs
+	./T17586
+	"$(TEST_HC)" $(TEST_HC_OPTS) -o T17586 ./T17586.hs -g3
+	./T17586

testsuite/tests/driver/T17586/T17586.hs

+main :: IO ()
+main = putStrLn "hello world"

testsuite/tests/driver/T17586/T17586.stdout

+[1 of 1] Compiling Main             ( T17586.hs, T17586.o )
+Linking T17586 ...
+hello world
+[1 of 1] Compiling Main             ( T17586.hs, T17586.o ) [flags changed]
+Linking T17586 ...
+hello world

testsuite/tests/driver/T17586/all.T

+test('T17586', normal, makefile_test, [])