[willpartcl]

Oversized nested replications such as {16777216{{256{1'b0}}}} wrap the computed width to zero before requireValidBitWidth runs. Constant folding then reaches a malformed value and can SIGSEGV. A nonzero wrap, such as count 16777217, fails similarly.

Perform the multiplication in a 64-bit SVInt so the existing width guard sees the complete result and emits ValueExceedsMaxBitWidth before folding. The signed 32-bit count and supported operand width fit safely in this width; valid limits and diagnostics stay unchanged.

Regression tests cover seven oversized count/width pairs with 0, 1, and x bits, plus valid small and maximum-width vectors. Before the fix the overflow regression SIGSEGVs while the maximum-width control passes. After the fix all 2,208 unit tests pass (22,128 assertions). The repository pre-commit checks pass on both changed files. Tests ran on SLURM; detailed logs are in /media/nvme1/tmp/will-issuefix/work/replication-width/.

Addresses partcleda/boson#5421; Boson will receive the fix via its yosys-slang submodule pin.

AI disclosure: implemented and tested with OpenAI Codex. Draft pending the human review required by CONTRIBUTING.md; no reviewer requested.

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