Add regression tests for class compatibility

Check that it is possible to assign an object to another object that is of
a type of any of its base classes. Also check that an error is reported if
this is not the case.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>

ivtest/ivltests/sv_class_compat1.v

@@ -0,0 +1,31 @@
+// Check that an object can be assigned to a variable of its base class type
+
+module test;
+
+  class B;
+    int x;
+
+    task t;
+      $display("PASSED");
+    endtask
+  endclass
+
+  class C extends B;
+    int y;
+
+    task t;
+      $display("FAILED");
+    endtask
+  endclass
+
+  B b;
+  C c;
+
+  initial begin
+    c = new;
+    b = c;
+
+    b.t;
+  end
+
+endmodule

ivtest/ivltests/sv_class_compat2.v

@@ -0,0 +1,40 @@
+// Check that an object can be assigned to a variable of base class across more
+// than one hierarchy level
+
+module test;
+
+  class B;
+    int x;
+
+    task t;
+      $display("PASSED");
+    endtask
+  endclass
+
+  class C extends B;
+    int y;
+
+    task t;
+      $display("FAILED");
+    endtask
+  endclass
+
+  class D extends C;
+    int z;
+
+    task t;
+      $display("FAILED");
+    endtask
+  endclass
+
+  B b;
+  D d;
+
+  initial begin
+    d = new;
+    b = d;
+
+    b.t;
+  end
+
+endmodule

ivtest/ivltests/sv_class_compat_fail1.v

@@ -0,0 +1,22 @@
+// Check that an error is reported when trying to assign an object to variable
+// of an unrelated class type
+
+module test;
+
+  class B;
+    int x;
+  endclass
+
+  class C;
+    int y;
+  endclass
+
+  B b;
+  C c;
+
+  initial begin
+    c = new;
+    b = c; // This should fail, both classes are unrelated
+  end
+
+endmodule

ivtest/ivltests/sv_class_compat_fail2.v

@@ -0,0 +1,22 @@
+// Check that an error is reported when trying when trying to assign an object
+// of a base class to a variable of a inherited class.
+
+module test;
+
+  class B;
+    int x;
+  endclass
+
+  class C extends B;
+    int y;
+  endclass
+
+  B b;
+  C c;
+
+  initial begin
+    b = new;
+    c = b; // This should fail, B is a base class of C
+  end
+
+endmodule

ivtest/ivltests/sv_class_compat_fail3.v

@@ -0,0 +1,27 @@
+// Check that an error is reported when trying to assign an object to a variable
+// that shares a common base class but is not directly related.
+
+module test;
+
+  class B;
+    int x;
+  endclass
+
+  class C extends B;
+    int y;
+  endclass
+
+  class D extends B;
+    int z;
+  endclass
+
+  C c;
+  D d;
+
+  initial begin
+    c = new;
+    d = c; // This should fail, both C and D inherit from B, but there is no
+           // direct relationship.
+  end
+
+endmodule

ivtest/regress-sv.list

@@ -531,6 +531,11 @@ sv_class21		normal,-g2009		ivltests
 sv_class22		normal,-g2009		ivltests
 sv_class23		normal,-g2009		ivltests
 sv_class24		normal,-g2009		ivltests
+sv_class_compat1	normal,-g2009		ivltests
+sv_class_compat2	normal,-g2009		ivltests
+sv_class_compat_fail1	CE,-g2009		ivltests
+sv_class_compat_fail2	CE,-g2009		ivltests
+sv_class_compat_fail3	CE,-g2009		ivltests
 sv_class_constructor1	normal,-g2009		ivltests
 sv_class_constructor_fail   CE,-g2009		ivltests
 sv_class_empty_item	normal,-g2009		ivltests

ivtest/regress-vlog95.list

@@ -404,6 +404,8 @@ sv_class21		CE,-g2009		ivltests
 sv_class22		CE,-g2009		ivltests
 sv_class23		CE,-g2009		ivltests
 sv_class24		CE,-g2009		ivltests
+sv_class_compat1	CE,-g2009		ivltests
+sv_class_compat2	CE,-g2009		ivltests
 sv_class_constructor1	CE,-g2009		ivltests
 sv_class_empty_item	CE,-g2009		ivltests
 sv_class_extends_scoped	CE,-g2009		ivltests