loplugin:implicitboolconversion workaround

after
    commit eb6819e74a
    Date:   Sat May 1 22:13:37 2021 +0900
    change usage of boost::hash_combine to o3tl::hash_combine

Change-Id: Idc70726f7e762b49111e6505ba3f978370d7cf7c
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/115399
Reviewed-by: Tor Lillqvist <tml@collabora.com>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
Tested-by: Jenkins

compilerplugins/clang/implicitboolconversion.cxx

@@ -907,6 +907,12 @@ void ImplicitBoolConversion::reportWarning(ImplicitCastExpr const * expr) {
                 }
             }
         }
+
+        // ignore template magic
+        StringRef aFileName = getFilenameOfLocation(compiler.getSourceManager().getSpellingLoc(compat::getBeginLoc(expr)));
+        if (loplugin::hasPathnamePrefix(aFileName, SRCDIR "/include/o3tl/hash_combine.hxx"))
+            return;
+
         report(
             DiagnosticsEngine::Warning,
             "implicit conversion (%0) from %1 to %2", compat::getBeginLoc(expr))