Index: b/src/widgets/NumericTextCtrl.cpp
===================================================================
--- a/src/widgets/NumericTextCtrl.cpp	2021-03-09 12:19:38.000000000 +0200
+++ b/src/widgets/NumericTextCtrl.cpp	2021-04-08 10:00:19.126519391 +0200
@@ -677,6 +677,7 @@ static const BuiltinFormatString Bandwid
          case NumericConverter::BANDWIDTH:
             return WXSIZEOF(BandwidthConverterFormats_);
       }
+      return WXSIZEOF(BandwidthConverterFormats_);
    }
 }
 
Index: b/lib-src/libnyquist/nyquist/xlisp/xlbfun.c
===================================================================
--- a/lib-src/libnyquist/nyquist/xlisp/xlbfun.c	2021-03-09 12:19:38.000000000 +0200
+++ b/lib-src/libnyquist/nyquist/xlisp/xlbfun.c	2021-04-08 10:00:19.174520965 +0200
@@ -603,7 +603,10 @@ LVAL xcleanup(void)
 {
     xllastarg();
     xlcleanup();
-    /* compiler might (wrongly) complain there is no return value */
+    /* this point will never be reached because xlcleanup() does a
+    longjmp(). The return is added to avoid false positive
+    error messages from static analyzers and compilers */
+    return (NIL);
 }
 
 /* xtoplevel - special form 'top-level' */
Index: b/lib-src/portsmf/allegro.cpp
===================================================================
--- a/lib-src/portsmf/allegro.cpp	2021-03-09 12:19:38.000000000 +0200
+++ b/lib-src/portsmf/allegro.cpp	2021-04-08 10:00:19.186521359 +0200
@@ -2885,6 +2885,9 @@ Alg_event_ptr &Alg_seq::operator[](int i
         tr++;
     }
     assert(false); // out of bounds
+    Alg_event_ptr ab_track;
+    return ab_track; // Fix false positive error: control reaches end of non-void function [-Werror=return-type]
+    // Ignores the assert A gcc bug?
 }
 #pragma warning(default: 4715)
 
Index: b/lib-src/libnyquist/nyquist/cmupv/src/cmupv.c
===================================================================
--- a/lib-src/libnyquist/nyquist/cmupv/src/cmupv.c	2021-03-09 12:19:38.000000000 +0200
+++ b/lib-src/libnyquist/nyquist/cmupv/src/cmupv.c	2021-04-08 11:22:54.394897011 +0200
@@ -600,6 +600,7 @@ double pv_get_effective_pos(Phase_vocode
         return -(pv->ratio * pv->fftsize / 2.0);
     } // I can't think of any other case.
     assert(FALSE);
+    return(0);
 }