Add regression tests for invalid index component contexts

Consolidating variable dimensions and hierarchy indices into a shared
grammar makes all index component forms parse in either context.

Check that `+:` and `-:` indexed part selects are rejected as dimensions,
and that `[]` and `[$:N]` are rejected as hierarchy indices. These forms
were previously excluded by the context-specific grammar rules.

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

ivtest/ivltests/dimension_idx_down_fail.v

@@ -0,0 +1,5 @@
+// Check that a descending indexed part select is not a dimension.
+
+module test;
+  reg value[1 -: 2];
+endmodule

ivtest/ivltests/dimension_idx_up_fail.v

@@ -0,0 +1,5 @@
+// Check that an ascending indexed part select is not a dimension.
+
+module test;
+  reg value[0 +: 2];
+endmodule

ivtest/ivltests/hier_index_empty_fail.v

@@ -0,0 +1,6 @@
+// Check that an empty index is not allowed in a hierarchy identifier.
+
+module test;
+  reg [3:0] value;
+  initial $display("%b", value[]);
+endmodule

ivtest/ivltests/hier_index_queue_fail.v

@@ -0,0 +1,6 @@
+// Check that a queue bound is not allowed in a hierarchy identifier.
+
+module test;
+  reg [3:0] value;
+  initial $display("%b", value[$:1]);
+endmodule

ivtest/regress-vvp.list

@@ -137,6 +137,8 @@ dffsynth8			vvp_tests/dffsynth8.json
 dffsynth9			vvp_tests/dffsynth9.json
 dffsynth10			vvp_tests/dffsynth10.json
 dffsynth11			vvp_tests/dffsynth11.json
+dimension_idx_down_fail		vvp_tests/dimension_idx_down_fail.json
+dimension_idx_up_fail		vvp_tests/dimension_idx_up_fail.json
 drive_strength4			vvp_tests/drive_strength4.json
 dumpfile			vvp_tests/dumpfile.json
 early_sig_elab1			vvp_tests/early_sig_elab1.json
@@ -150,6 +152,8 @@ fmonitor1			vvp_tests/fmonitor1.json
 fmonitor2			vvp_tests/fmonitor2.json
 fread-error			vvp_tests/fread-error.json
 func_nested_block_nb_fail	vvp_tests/func_nested_block_nb_fail.json
+hier_index_empty_fail		vvp_tests/hier_index_empty_fail.json
+hier_index_queue_fail		vvp_tests/hier_index_queue_fail.json
 line_directive			vvp_tests/line_directive.json
 localparam_type			vvp_tests/localparam_type.json
 macro_str_esc			vvp_tests/macro_str_esc.json

ivtest/vvp_tests/dimension_idx_down_fail.json

@@ -0,0 +1,5 @@
+{
+    "type"          : "CE",
+    "source"        : "dimension_idx_down_fail.v",
+    "iverilog-args" : [ "-g2001" ]
+}

ivtest/vvp_tests/dimension_idx_up_fail.json

@@ -0,0 +1,5 @@
+{
+    "type"          : "CE",
+    "source"        : "dimension_idx_up_fail.v",
+    "iverilog-args" : [ "-g2001" ]
+}

ivtest/vvp_tests/hier_index_empty_fail.json

@@ -0,0 +1,5 @@
+{
+    "type"          : "CE",
+    "source"        : "hier_index_empty_fail.v",
+    "iverilog-args" : [ "-g2005-sv" ]
+}

ivtest/vvp_tests/hier_index_queue_fail.json

@@ -0,0 +1,5 @@
+{
+    "type"          : "CE",
+    "source"        : "hier_index_queue_fail.v",
+    "iverilog-args" : [ "-g2005-sv" ]
+}