Resolve package types in interfaces (#3658)

* Resolve package types in interfaces
* Added test for resolving of package types in interfaces

tests/svinterfaces/resolve_types.sv

@@ -0,0 +1,24 @@
+// This test checks that types, including package types, are resolved from within an interface.
+
+typedef logic [7:0] x_t;
+
+package pkg;
+    typedef logic [7:0] y_t;
+endpackage
+
+interface iface;
+    x_t x;
+    pkg::y_t y;
+endinterface
+
+module dut (input logic [7:0] x, output logic [7:0] y);
+  iface intf();
+  assign intf.x = x;
+  assign y = intf.y;
+
+  ondemand u(.intf);
+endmodule
+
+module ref (input logic [7:0] x, output logic [7:0] y);
+  assign y = ~x;
+endmodule

tests/svinterfaces/resolve_types.ys

@@ -0,0 +1,6 @@
+read_verilog -sv resolve_types.sv
+hierarchy -libdir . -check
+flatten
+equiv_make ref dut equiv
+equiv_simple
+equiv_status -assert

tests/svinterfaces/run-test.sh

@@ -4,3 +4,4 @@
 ./runone.sh  svinterface_at_top
 
 ./run_simple.sh load_and_derive
+./run_simple.sh resolve_types