Fix calls from NET_RECEIVE.

src/codegen/codegen_neuron_cpp_visitor.cpp

@@ -2129,6 +2129,10 @@ void CodegenNeuronCppVisitor::print_net_receive() {
     printer->add_line("auto * _ppvar = _nrn_mechanism_access_dparam(_pnt->prop);");
 
     printer->fmt_line("auto inst = make_instance_{}(_lmc);", info.mod_suffix);
+    printer->fmt_line("// nocmodl has a nullptr dereference for thread variables.");
+    printer->fmt_line("// NMODL will fail to compile at a later point, because of");
+    printer->fmt_line("// missing '_thread_vars'.");
+    printer->fmt_line("Datum * _thread = nullptr;");
 
     printer->add_line("size_t id = 0;");
     printer->add_line("double t = _nt->_t;");

test/usecases/NetReceiveCalls.mod

@@ -0,0 +1,27 @@
+NEURON {
+    POINT_PROCESS NetReceiveCalls
+    RANGE c1, c2
+}
+
+ASSIGNED {
+    c1
+    c2
+}
+
+INITIAL {
+    c1 = 0
+    c2 = 0
+}
+
+FUNCTION one() {
+    one = 1
+}
+
+PROCEDURE increment_c2() {
+    c2 = c2 + 2
+}
+
+NET_RECEIVE(w) {
+    c1 = c1 + one()
+    increment_c2()
+}

test/usecases/net_receive/test_calls.py

@@ -0,0 +1,29 @@
+import numpy as np
+
+from neuron import h, gui
+from neuron.units import ms
+
+
+def test_calls():
+    nseg = 1
+
+    soma = h.Section()
+    soma.nseg = nseg
+
+    syn = h.NetReceiveCalls(soma(0.5))
+
+    stim = h.NetStim()
+    stim.interval = 0.2
+    stim.number = 3
+    stim.start = 0.1
+
+    netcon = h.NetCon(stim, syn)
+
+    h.stdinit()
+    h.run()
+
+    assert syn.c1 == 3
+    assert syn.c2 == 6
+
+if __name__ == "__main__":
+    test_calls()