verilog: fix multiple AST_PREFIX scope resolution issues

- Root AST_PREFIX nodes are now subject to genblk expansion to allow
  them to refer to a locally-visible generate block
- Part selects on AST_PREFIX member leafs can now refer to generate
  block items (previously would not resolve and raise an error)
- Add source location information to AST_PREFIX nodes

tests/verilog/prefix.sv

@@ -0,0 +1,95 @@
+module top;
+    genvar i, j;
+    if (1) begin : blk1
+        integer a = 1;
+        for (i = 0; i < 2; i = i + 1) begin : blk2
+            integer b = i;
+            for (j = 0; j < 2; j = j + 1) begin : blk3
+                integer c = j;
+                localparam x = i;
+                localparam y = j;
+                always @* begin
+                    assert (1 == a);
+                    assert (1 == blk1.a);
+                    assert (1 == top.blk1.a);
+                    assert (i == b);
+                    assert (i == blk2[i].b);
+                    assert (i == blk1.blk2[i].b);
+                    assert (i == top.blk1.blk2[i].b);
+                    assert (i == blk2[x].b);
+                    assert (i == blk1.blk2[x].b);
+                    assert (i == top.blk1.blk2[x].b);
+                    assert (j == c);
+                    assert (j == blk3[j].c);
+                    assert (j == blk2[x].blk3[j].c);
+                    assert (j == blk1.blk2[x].blk3[j].c);
+                    assert (j == top.blk1.blk2[x].blk3[j].c);
+                    assert (j == c);
+                    assert (j == blk3[y].c);
+                    assert (j == blk2[x].blk3[y].c);
+                    assert (j == blk1.blk2[x].blk3[y].c);
+                    assert (j == top.blk1.blk2[x].blk3[y].c);
+                    assert (j == top.blk1.blk2[x].blk3[y].c[0]);
+                    assert (0 == top.blk1.blk2[x].blk3[y].c[1]);
+                    assert (0 == top.blk1.blk2[x].blk3[y].c[j]);
+                end
+            end
+            always @* begin
+                assert (1 == a);
+                assert (1 == blk1.a);
+                assert (1 == top.blk1.a);
+                assert (i == b);
+                assert (i == blk2[i].b);
+                assert (i == blk1.blk2[i].b);
+                assert (i == top.blk1.blk2[i].b);
+                assert (0 == blk3[0].c);
+                assert (0 == blk2[i].blk3[0].c);
+                assert (0 == blk1.blk2[i].blk3[0].c);
+                assert (0 == top.blk1.blk2[i].blk3[0].c);
+                assert (1 == blk3[1].c);
+                assert (1 == blk2[i].blk3[1].c);
+                assert (1 == blk1.blk2[i].blk3[1].c);
+                assert (1 == top.blk1.blk2[i].blk3[1].c);
+            end
+        end
+        always @* begin
+            assert (1 == a);
+            assert (1 == blk1.a);
+            assert (1 == top.blk1.a);
+            assert (0 == blk2[0].b);
+            assert (0 == blk1.blk2[0].b);
+            assert (0 == top.blk1.blk2[0].b);
+            assert (1 == blk2[1].b);
+            assert (1 == blk1.blk2[1].b);
+            assert (1 == top.blk1.blk2[1].b);
+            assert (0 == blk2[0].blk3[0].c);
+            assert (0 == blk1.blk2[0].blk3[0].c);
+            assert (0 == top.blk1.blk2[0].blk3[0].c);
+            assert (1 == blk2[0].blk3[1].c);
+            assert (1 == blk1.blk2[0].blk3[1].c);
+            assert (1 == top.blk1.blk2[0].blk3[1].c);
+            assert (0 == blk2[1].blk3[0].c);
+            assert (0 == blk1.blk2[1].blk3[0].c);
+            assert (0 == top.blk1.blk2[1].blk3[0].c);
+            assert (1 == blk2[1].blk3[1].c);
+            assert (1 == blk1.blk2[1].blk3[1].c);
+            assert (1 == top.blk1.blk2[1].blk3[1].c);
+        end
+    end
+    always @* begin
+        assert (1 == blk1.a);
+        assert (1 == top.blk1.a);
+        assert (0 == blk1.blk2[0].b);
+        assert (0 == top.blk1.blk2[0].b);
+        assert (1 == blk1.blk2[1].b);
+        assert (1 == top.blk1.blk2[1].b);
+        assert (0 == blk1.blk2[0].blk3[0].c);
+        assert (0 == top.blk1.blk2[0].blk3[0].c);
+        assert (1 == blk1.blk2[0].blk3[1].c);
+        assert (1 == top.blk1.blk2[0].blk3[1].c);
+        assert (0 == blk1.blk2[1].blk3[0].c);
+        assert (0 == top.blk1.blk2[1].blk3[0].c);
+        assert (1 == blk1.blk2[1].blk3[1].c);
+        assert (1 == top.blk1.blk2[1].blk3[1].c);
+    end
+endmodule

tests/verilog/prefix.ys

@@ -0,0 +1,5 @@
+read_verilog -sv prefix.sv
+hierarchy
+proc
+select -module top
+sat -verify -seq 1 -prove-asserts -show-all