1 files changed, 3 insertions, 1 deletions
diff --git a/src/gui/text/qfont.cpp b/src/gui/text/qfont.cpp
index f2951611ff..12761d0d3e 100644
--- a/src/gui/text/qfont.cpp
+++ b/src/gui/text/qfont.cpp
@@ -2533,7 +2533,9 @@ bool QFontInfo::fixedPitch() const
         QChar ch[2] = { QLatin1Char('i'), QLatin1Char('m') };
         QGlyphLayoutArray<2> g;
         int l = 2;
-        engine->stringToCMap(ch, 2, &g, &l, 0);
+        if (!engine->stringToCMap(ch, 2, &g, &l, 0))
+            Q_UNREACHABLE();
+        Q_ASSERT(l == 2);
         engine->fontDef.fixedPitch = g.advances[0] == g.advances[1];
         engine->fontDef.fixedPitchComputed = true;
     }