Generic type for map value cannot be inferred from a value argument

[prantlf]

Describe the bug

Compiling this code:

fn f[T](src map[string]T) {
}

f({ 'a': 1 })

fails with the following error:

bug_map.v:6:10: error: invalid map value: expected `T`, not `int literal`
    4 | // m := { 'a': 1 }
    5 | // f(m)
    6 | f({ 'a': 1 })
      |          ^

Expected Behavior

The compilation should succeed resolving the function to:

fn f[int](src map[string]int)

Current Behavior

The compilation fails with the message above.

Reproduction Steps

1. Save the script above to a file bug_map.v.
2. Run v bug_map.v on the command line.

Or try it at https://vosca.dev/p/27605a3527.

Possible Solution

I wish I knew :-)

Additional Information/Context

It appears to be connected to maybe just parsing the value and not storing temporarily its type. If the value argument in the function call:

f({ 'a': 1 })

is replaced with a variable, which has probably its type generated, the compilation succeeds:

m := { 'a': 1 }
f(m)

See at https://vosca.dev/p/2d10eaa9f8.

V version

V 0.3.4 4e21b2a

Environment details (OS name and version, etc.)

V full version: V 0.3.4 1be798b.4e21b2a
OS: macos, macOS, 13.3.1, 22E772610a
Processor: 12 cpus, 64bit, little endian, Intel(R) Core(TM) i7-8850H CPU @ 2.60GHz

getwd: /Users/prantlf/Sources/github/v-yaml
vexe: /usr/local/Cellar/vlang/0.3.4/libexec/v
vexe mtime: 2023-06-03 11:39:19

vroot: OK, value: /usr/local/Cellar/vlang/0.3.4/libexec
VMODULES: OK, value: /Users/prantlf/.vmodules
VTMP: OK, value: /tmp/v_501

Git version: git version 2.41.0
Git vroot status: weekly.2023.22-6-g4e21b2ab
.git/config present: true

CC version: Apple clang version 14.0.3 (clang-1403.0.22.14.1)
thirdparty/tcc status: thirdparty-macos-amd64 46662e2