error on reading input from shell pipe

[lost22git]

Describe the bug

; cat demo.v | v fmt
V panic: tos(): nil string
v hash: 36bef92

Reproduction Steps

N/A

Expected Behavior

N/A

Current Behavior

N/A

Possible Solution

No response

Additional Information/Context

No response

V version

V 0.4.10 36bef92

Environment details (OS name and version, etc.)

|V full version      |V 0.4.10 36bef926fb9642378f6514886af7ce16279357f5
|:-------------------|:-------------------
|OS                  |termux, 3.18.120-perf+, #1 SMP PREEMPT Mon Nov 4 21:20:22 HKT 2019
|Processor           |4 cpus, 64bit, little endian
|Memory              |N/A
|                    |
|V executable        |/data/data/com.termux/files/home/code/v/v
|V last modified time|2025-06-12 07:03:05
|                    |
|V home dir          |OK, value: /data/data/com.termux/files/home/code/v
|VMODULES            |OK, value: /data/data/com.termux/files/home/.vmodules
|VTMP                |OK, value: /data/data/com.termux/files/usr/tmp/v_10459
|Current working dir |OK, value: /data/data/com.termux/files/home/code/hello/v
|                    |
|Git version         |git version 2.49.0
|V git status        |36bef926
|.git/config present |true
|                    |
|cc version          |clang version 20.1.6
|gcc version         |clang version 20.1.6
|clang version       |clang version 20.1.6
|tcc version         |N/A
|tcc git status      |thirdparty-unknown-unknown de82a130
|emcc version        |N/A
|glibc version       |readelf: Error: 'readlink (GNU coreutils) 9.7

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