sip-2.18.1-cast-fix_from-8e9e02f1bea0.diff

diff --git a/sipgen/gencode.c b/sipgen/gencode.c
index c5707ef..7b477a8 100644
--- a/sipgen/gencode.c
+++ b/sipgen/gencode.c
@@ -5913,15 +5913,20 @@ static void generateClassFunctions(sipSpec *pt, moduleDef *mod, classDef *cd,
         else if (md->slot != no_slot)
             generateSlot(mod, cd, NULL, md, fp);
 
-    /* The cast function. */
-    if (needsCastFunction(cd))
+    /*
+     * The cast function.  Note that we used to try and work out if the cast
+     * function was really needed (eg. only for multiple inheritance) but there
+     * are subtle cases where, even for single inheritance, it is needed.  We
+     * take the conservative approach and generate it for all derived classes.
+     */
+    if (cd->supers != NULL)
     {
         mroDef *mro;
 
         prcode(fp,
 "\n"
 "\n"
-"/* Cast a pointer to a type somewhere in its multiple inheritance hierarchy. */\n"
+"/* Cast a pointer to a type somewhere in its inheritance hierarchy. */\n"
 "extern \"C\" {static void *cast_%L(void *, const sipTypeDef *);}\n"
 "static void *cast_%L(void *sipCppV, const sipTypeDef *targetType)\n"
 "{\n"
@@ -5935,9 +5940,10 @@ static void generateClassFunctions(sipSpec *pt, moduleDef *mod, classDef *cd,
 "\n"
             );
 
-        for (mro = cd->mro; mro != NULL; mro = mro->next)
+        /* Skip the the class itself. */
+        for (mro = cd->mro->next; mro != NULL; mro = mro->next)
         {
-            if (needsCast(mro) && !isDuplicateSuper(mro) && !hasDuplicateSuper(mro))
+            if (!isDuplicateSuper(mro) && !hasDuplicateSuper(mro))
             {
                 prcode(fp,
 "    if (targetType == sipType_%C)\n"
@@ -10446,7 +10452,7 @@ static void generateTypeDefinition(sipSpec *pt, classDef *cd, FILE *fp)
 "    release_%L,\n"
             , cd->iff);
 
-    if (needsCastFunction(cd))
+    if (cd->supers != NULL)
         prcode(fp,
 "    cast_%L,\n"
             , cd->iff);
diff --git a/sipgen/sip.h b/sipgen/sip.h
index 562058d..a5ed8a4 100644
--- a/sipgen/sip.h
+++ b/sipgen/sip.h
@@ -205,7 +205,6 @@
 #define CLASS2_TMPL_ARG     0x01        /* The class is a template argument. */
 #define CLASS2_MIXIN        0x02        /* The class is a mixin. */
 #define CLASS2_EXPORT_DERIVED   0x04    /* Export the derived class declaration. */
-#define CLASS2_NEEDS_CAST_FUNC  0x08    /* The class needs a cast function. */
 
 #define isTemplateArg(cd)   ((cd)->classflags2 & CLASS2_TMPL_ARG)
 #define setTemplateArg(cd)  ((cd)->classflags2 |= CLASS2_TMPL_ARG)
@@ -213,8 +212,6 @@
 #define setMixin(cd)        ((cd)->classflags2 |= CLASS2_MIXIN)
 #define isExportDerived(cd) ((cd)->classflags2 & CLASS2_EXPORT_DERIVED)
 #define setExportDerived(cd)    ((cd)->classflags2 |= CLASS2_EXPORT_DERIVED)
-#define needsCastFunction(cd)   ((cd)->classflags2 & CLASS2_NEEDS_CAST_FUNC)
-#define setNeedsCastFunction(cd)    ((cd)->classflags2 |= CLASS2_NEEDS_CAST_FUNC)
 
 
 /* Handle ctor flags.  These are combined with the section flags. */
@@ -293,7 +290,6 @@
 #define HIER_IS_DUPLICATE   0x0001      /* It is a super class duplicate. */
 #define HIER_HAS_DUPLICATE  0x0002      /* It has a super class duplicate. */
 #define HIER_BEING_SET      0x0004      /* The MRO is being set. */
-#define HIER_NEEDS_CAST     0x0008      /* The class needs an explicit cast. */
 
 #define isDuplicateSuper(m) ((m)->mroflags & HIER_IS_DUPLICATE)
 #define setIsDuplicateSuper(m)  ((m)->mroflags |= HIER_IS_DUPLICATE)
@@ -302,8 +298,6 @@
 #define hierBeingSet(m)     ((m)->mroflags & HIER_BEING_SET)
 #define setHierBeingSet(m)  ((m)->mroflags |= HIER_BEING_SET)
 #define resetHierBeingSet(m)    ((m)->mroflags &= ~HIER_BEING_SET)
-#define needsCast(m)        ((m)->mroflags & HIER_NEEDS_CAST)
-#define setNeedsCast(m)     ((m)->mroflags |= HIER_NEEDS_CAST)
 
 
 /* Handle overload flags.  These are combined with the section flags. */
diff --git a/sipgen/transform.c b/sipgen/transform.c
index 775c98f..0d88af9 100644
--- a/sipgen/transform.c
+++ b/sipgen/transform.c
@@ -1237,24 +1237,11 @@ static void setHierarchy(sipSpec *pt, classDef *base, classDef *cd,
             /* Make sure the super-class's hierarchy has been done. */
             setHierarchy(pt, base, cl->cd, head);
 
-            if (needsCastFunction(cl->cd))
-                setNeedsCastFunction(cd);
-
             /* Append the super-classes hierarchy. */
             for (mro = cl->cd->mro; mro != NULL; mro = mro->next)
             {
                 mroDef *new_mro = appendToMRO(cd->mro, &tailp, mro->cd);
 
-                if (cl != cd->supers || needsCast(mro))
-                {
-                    /*
-                     * It's not the class's first super-class so it will need a
-                     * cast function.
-                     */
-                    setNeedsCast(new_mro);
-                    setNeedsCastFunction(cd);
-                }
-
                 if (isDeprecatedClass(mro->cd))
                     setIsDeprecatedClass(cd);