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Describe the bug

Running ./v -g -o vdbg cmd/v && ./vdbg 'generic_fn_return.v' && 'generic_fn_return' on generic_fn_return.v produced a compiler error.

Reproduction Steps

./v -g -o vdbg cmd/v && ./vdbg 'generic_fn_return.v' && 'generic_fn_return'

fn foo[T](do fn () !T) !T {
    mut r := T{}
    r = do()!
    return r
}

fn main() {
    docb := fn () !int {
        return -1
    }
    r := foo(docb)!
    assert r == -1
}

Expected Behavior

Successful compilation and passed assert.

Current Behavior

================== C compilation error (from tcc): ==============
cc: /tmp/v_1000/generic_fn_return.01KR1TN1DGENRFD9V8GM7MN9P3.tmp.c:8553: error: '{' expected (got ";")
=================================================================
Try passing `-g` when compiling, to see a .v file:line information, that correlates more with the C error.
(Alternatively, pass `-show-c-output`, to print the full C error message).
builder error: 
==================
C error found while compiling generated C code.
This can be caused by invalid C interop code, C compiler flags, or a V compiler bug.
If your code is pure V and this still happens, please report it using `v bug file.v`,
or goto https://github.com/vlang/v/issues/new/choose .
You can also use #help on Discord: https://discord.gg/vlang .

Possible Solution

No response

Additional Information/Context

Generated by v bug from generic_fn_return.v.

V version

V 0.5.1 701d7f3

Environment details (OS name and version, etc.)

|V full version      |V 0.5.1 2f3c0f1f397c08bfc5ef73e7ff62794471b2b811.701d7f3
|:-------------------|:-------------------
|OS                  |linux, Linux version 7.0.3-arch1-1 (linux@archlinux) (gcc (GCC) 15.2.1 20260209, GNU ld (GNU Binutils) 2.46) #1 SMP PREEMPT_DYNAMIC Thu, 30 Apr 2026 18:41:12 +0000
|Processor           |16 cpus, 64bit, little endian, 12th Gen Intel(R) Core(TM) i5-1240P
|Memory              |4.13GB/15.34GB
|                    |
|V executable        |/home/ge/.vlang/v
|V last modified time|2026-05-07 18:19:14
|                    |
|V home dir          |OK, value: /home/ge/.vlang
|VMODULES            |OK, value: /home/ge/.vmodules
|VTMP                |OK, value: /tmp/v_1000
|Current working dir |OK, value: /tmp
|                    |
|Git version         |git version 2.54.0
|V git status        |weekly.2026.03-1869-g701d7f37
|.git/config present |true
|                    |
|cc version          |cc (GCC) 15.2.1 20260209
|gcc version         |gcc (GCC) 15.2.1 20260209
|clang version       |clang version 22.1.3
|tcc version         |tcc version 0.9.28rc 2025-02-13 HEAD@f8bd136d (x86_64 Linux)
|tcc git status      |thirdparty-linux-amd64 696c1d84
|emcc version        |N/A
|glibc version       |ldd (GNU libc) 2.43

C error on returning generic anon fn result #31