Files
Nim/tests
Corey Leavitt 73986c03a1 fixes #25857; don't treat typeof(result) as a use-before-init of result (#25858)
fixes #25857

## Bug

`typeof(result)` inside the expression that builds `result` gets counted
as a read
of `result` before it's set. On a `{.requiresInit.}` return type that's
a hard error
("'result' requires explicit initialization"). `typeof` never evaluates
its operand,
so it's a false positive. On 2.2.4 it compiles, but the same line still
emits a bogus
`ProveInit` warning, so no released version gets it right.

Regression from #25151. That PR made a used-before-init `requiresInit`
result a hard
error instead of a warning, which is correct on its own. The side effect
was that
this old false-positive warning became a build error.

## Root cause

`track` in `compiler/sempass2.nim` has no arm for `nkTypeOfExpr`, so it
hits the
default that recurses into every child, reaches the `result` `nkSym`
inside the
`typeof`, and calls `useVar`. `sizeof`/`compiles`/`declared` don't hit
this because
they fold to a constant before `track` runs. A `typeof(result)` typedesc
argument
survives into `track`.

## Fix

Skip `nkTypeOfExpr` in `track`. Its operand is never evaluated, so it
isn't a
definite-assignment use. After the patch there's no error and no warning
here, even
with `--warnings:on`. The #25151 check is untouched: a real use of
`result` before
init is a plain `nkSym`, not inside a `typeof`, so it still reaches
`useVar`.

## Test

`tests/init/t25857.nim`, a positive test that compiles and prints `1`.

## Checks

- Repro compiles and runs on patched 2.2.6 and patched devel.
- `tests/errmsgs/t25117.nim` still fails as expected. A real
`xxx(result)` before
  init still errors.
- `testament cat init` and `testament cat errmsgs` green on patched
devel (55 tests,
  0 failures), including the `--warningAsError:ProveInit` tests.
- Bisect: parent `1ab68797` good, `576c4018` (#25151) bad.
2026-06-02 07:07:44 +02:00
..
2026-04-07 18:07:34 +02:00
2024-06-06 00:52:01 +02:00
2021-08-21 08:22:00 +02:00
2026-04-02 07:19:43 +02:00
2026-02-23 13:39:55 +01:00
2025-02-06 23:19:53 +01:00
2023-07-22 21:11:08 +02:00
2026-05-12 23:20:10 +02:00
2026-02-10 13:21:35 +01:00
2025-12-18 18:54:03 +01:00
2026-05-29 08:08:42 +02:00
2026-04-20 20:13:06 +02:00
2025-03-29 13:28:28 +01:00
2022-12-22 08:32:12 +01:00
2013-03-16 23:53:07 +01:00
2020-12-28 14:13:21 +01:00

This directory contains the test cases.

Each test must have a filename of the form: t*.nim

Note: Testament is only aware of tests under a directory (eg tests/foo/) and will ignore top-level tests like tests/tbar.nim.

Specs

Each test can contain a spec in a discard """ ... """ block.

Check out the parseSpec procedure in the specs module for a full and reliable reference

action

Specifies what action this test should take.

Default: run

Options:

  • compile - compiles the module and fails the test if compilations fails.
  • run - compiles and runs the module, fails the test if compilation or execution of test code fails.
  • reject - compiles the module and fails the test if compilation succeeds.

There are certain spec keys that imply run, including output and outputsub.

Categories

Each folder under this directory represents a test category, which can be tested by running koch tests pcat <category> (or cat to avoid parallel testing, which is slower).

The folder dll contains simple DLL tests.

The folder realtimeGC contains a test for validating that the realtime GC can run properly without linking against the nimrtl.dll/so.