Fix reference counting in cypclass locks

Cython/Compiler/ExprNodes.py

@@ -14329,9 +14329,8 @@ class CoerceToLockedNode(CoercionNode):
     def generate_disposal_code(self, code):
         # Close the scope to release the lock.
         code.putln("}")
-        # Dispose of and free subexpressions.
-        self.arg.generate_subexpr_disposal_code(code)
-        self.arg.free_subexpr_temps(code)
+        # Dispose of the temporary without decrefing.
+        self.arg.generate_post_assignment_code(code)
 
 
 class CoerceToArgAssmtNode(CoercionNode):

Cython/Compiler/Nodes.py

@@ -8630,7 +8630,8 @@ class LockCypclassNode(StatNode):
         self.obj.analyse_declarations(env)
 
     def analyse_expressions(self, env):
-        self.obj = obj = self.obj.analyse_types(env)
+        obj = self.obj.analyse_types(env)
+        self.obj = obj.coerce_to_temp(env)
         self.body = self.body.analyse_expressions(env)
         if not obj.type.is_cyp_class:
             error(obj.pos, "Locking non-cypclass reference")
@@ -8666,6 +8667,11 @@ class LockCypclassNode(StatNode):
         # Close the scope to release the lock.
         code.putln("}")
 
+        # Dispose of the temporary without decrefing.
+        self.obj.generate_post_assignment_code(code)
+        # Free the temporary.
+        self.obj.free_temps(code)
+
 
 def cython_view_utility_code():
     from . import MemoryView

Cython/Utility/CyObjects.cpp

@@ -320,6 +320,7 @@
                 ~Cy_rlock_guard() {
                     if (this->o != NULL) {
                         this->o->CyObject_UNRLOCK();
+                        this->o->CyObject_DECREF();
                     }
                     else {
                         fprintf(stderr, "ERROR: trying to unrlock NULL !\n");
@@ -341,6 +342,7 @@
                 ~Cy_wlock_guard() {
                     if (this->o != NULL) {
                         this->o->CyObject_UNWLOCK();
+                        this->o->CyObject_DECREF();
                     }
                     else {
                         fprintf(stderr, "ERROR: trying to unwlock NULL !\n");