Fix crash streaming an unpacked array of unpacked structs (#7917)

src/V3Const.cpp

@@ -2780,9 +2780,8 @@ class ConstVisitor final : public VNVisitor {
                 streamp->dtypeSetLogicUnsized(packedp->width(), packedp->widthMin(),
                                               VSigning::UNSIGNED);
                 srcp = packedp;
-            }
+            } else if ((VN_IS(srcDTypep, QueueDType) || VN_IS(srcDTypep, DynArrayDType)
-            if ((VN_IS(srcDTypep, QueueDType) || VN_IS(srcDTypep, DynArrayDType)
+                        || VN_IS(srcDTypep, UnpackArrayDType))) {
-                 || VN_IS(srcDTypep, UnpackArrayDType))) {
                 if (VN_IS(dstDTypep, QueueDType) || VN_IS(dstDTypep, DynArrayDType)) {
                     int blockSize = 1;
                     if (const AstConst* const constp = VN_CAST(streamp->rhsp(), Const)) {

test_regress/t/t_stream_unpacked_array_struct.py

@@ -0,0 +1,18 @@
+#!/usr/bin/env python3
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# This program is free software; you can redistribute it and/or modify it
+# under the terms of either the GNU Lesser General Public License Version 3
+# or the Perl Artistic License Version 2.0.
+# SPDX-FileCopyrightText: 2026 Wilson Snyder
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+import vltest_bootstrap
+
+test.scenarios('simulator')
+
+test.compile()
+
+test.execute()
+
+test.passes()

test_regress/t/t_stream_unpacked_array_struct.v

@@ -0,0 +1,60 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This program is free software; you can redistribute it and/or modify it
+// under the terms of either the GNU Lesser General Public License Version 3
+// or the Perl Artistic License Version 2.0.
+// SPDX-FileCopyrightText: 2026 Wilson Snyder
+// SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+// Ref. to IEEE 1800-2023 11.4.14
+//
+// Streaming an unpacked array whose element is an unpacked struct.  The left
+// stream ({<<{}}) read used to crash V3EmitC: V3Const packed the aggregate
+// source but then re-wrapped the now-packed expression in AstCvtArrayToPacked,
+// which EmitC dereferenced as an array.
+
+module t(  /*AUTOARG*/
+    // Inputs
+    clk
+);
+  input clk;
+
+  `define checkh(gotv, expv) \
+    do if ((gotv) !== (expv)) begin \
+      $write("%%Error: %s:%0d: got='h%x exp='h%x\n", `__FILE__, `__LINE__, (gotv), (expv)); \
+      $stop; \
+    end while (0);
+
+  typedef struct {
+    logic [7:0] a;
+    logic [7:0] b;
+  } s_t;
+  typedef s_t arr_t[2];  // unpacked array of unpacked struct
+
+  localparam int W = $bits(arr_t);
+
+  integer cyc = 0;
+  reg [63:0] crc = 64'h5aef0c8d_d70a4497;
+  wire [W-1:0] src = crc[W-1:0];
+
+  arr_t aw_r, aw_l;
+  always_comb {>>{aw_r}} = src;
+  always_comb {<<8{aw_l}} = src;
+
+  wire [W-1:0] rd_r = {>>{aw_r}};
+  wire [W-1:0] rd_l = {<<8{aw_l}};  // {<<{}} read of aggregate array previously crashed
+
+  always @(posedge clk) begin
+    cyc <= cyc + 1;
+    crc <= {crc[62:0], crc[63] ^ crc[2] ^ crc[0]};
+    if (cyc > 1) begin
+      `checkh(rd_r, src);
+      `checkh(rd_l, src);
+    end
+    if (cyc == 20) begin
+      $write("*-* All Finished *-*\n");
+      $finish;
+    end
+  end
+
+endmodule