diff --git a/elab_lval.cc b/elab_lval.cc
index 1068954d1..4d14fdb83 100644
--- a/elab_lval.cc
+++ b/elab_lval.cc
@@ -883,8 +883,10 @@ bool PEIdent::elaborate_lval_net_idx_(Design*des,
       calculate_up_do_width_(des, scope, wid);
 
       NetExpr*base = elab_and_eval(des, scope, index_tail.msb, -1);
+      if (!base)
+	    return false;
 
-      if (base && base->expr_type() == IVL_VT_REAL) {
+      if (base->expr_type() == IVL_VT_REAL) {
 	    cerr << get_fileline() << ": error: Indexed part select base "
 	            "expression for ";
 	    cerr << lv->sig()->name() << "[" << *base;
diff --git a/ivtest/ivltests/sv_lval_idx_part_invalid_base_down_fail.v b/ivtest/ivltests/sv_lval_idx_part_invalid_base_down_fail.v
new file mode 100644
index 000000000..769a76899
--- /dev/null
+++ b/ivtest/ivltests/sv_lval_idx_part_invalid_base_down_fail.v
@@ -0,0 +1,9 @@
+// Check that invalid indexed part-select l-value bases report an error.
+
+module test;
+  reg [31:0] a;
+
+  initial begin
+    a[does_not_exist -: 2] = 2'b00;
+  end
+endmodule
diff --git a/ivtest/regress-vvp.list b/ivtest/regress-vvp.list
index 01b7d6e5f..b547f40e4 100644
--- a/ivtest/regress-vvp.list
+++ b/ivtest/regress-vvp.list
@@ -345,6 +345,7 @@ sv_lval_concat_uarray_fail1	vvp_tests/sv_lval_concat_uarray_fail1.json
 sv_lval_concat_uarray_fail2	vvp_tests/sv_lval_concat_uarray_fail2.json
 sv_lval_concat_uarray_fail3	vvp_tests/sv_lval_concat_uarray_fail3.json
 sv_lval_concat_uarray_fail4	vvp_tests/sv_lval_concat_uarray_fail4.json
+sv_lval_idx_part_invalid_base_down_fail	vvp_tests/sv_lval_idx_part_invalid_base_down_fail.json
 sv_mixed_assign1		vvp_tests/sv_mixed_assign1.json
 sv_mixed_assign2		vvp_tests/sv_mixed_assign2.json
 sv_mixed_assign_error1		vvp_tests/sv_mixed_assign_error1.json
diff --git a/ivtest/vvp_tests/sv_lval_idx_part_invalid_base_down_fail.json b/ivtest/vvp_tests/sv_lval_idx_part_invalid_base_down_fail.json
new file mode 100644
index 000000000..e04a3a978
--- /dev/null
+++ b/ivtest/vvp_tests/sv_lval_idx_part_invalid_base_down_fail.json
@@ -0,0 +1,5 @@
+{
+    "type"          : "CE",
+    "source"        : "sv_lval_idx_part_invalid_base_down_fail.v",
+    "iverilog-args" : [ "-g2001" ]
+}