website: add 2024.1 release notes

website/content/changes/2024.1.md

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+---
+title: Staticcheck 2024.1 release notes
+linkTitle: "2024.1 (v0.5.0)"
+weight: -9
+---
+
+## DRAFT RELEASE NOTES
+
+Staticcheck 2024.1 is not yet released. These are work-in-progress release
+notes. Staticcheck 2024.1 is expected to be released in August 2024.
+
+## Backwards incompatible changes
+
+Staticcheck 2024.1 contains the following backwards incompatible changes:
+
+- The `keyify` utility has been removed. The recommended alternative is gopls.
+- `staticcheck -merge` now exits with a non-zero status if any problems have
+  been found.
+
+## Improved Go 1.22 support
+
+This release updates Staticcheck's database of deprecated standard library APIs
+to cover the Go 1.22 release. Furthermore, checks have been updated to correctly
+handle the new "for" loop variable scoping behavior as well as ranging over
+integers.
+
+## Added Go 1.23 support
+
+Staticcheck 2024.1 has full support for iterators / range-over-func.
+Furthermore, {{< check "SA1015" >}} will skip any code targeting Go 1.23 or
+newer, as it is now possible to use `time.Tick` without leaking memory.
+
+## Improved handling of Go versions
+
+Go 1.21 more rigorously defined the meaning of the `go` directive in `go.mod`
+files, as well as its interactions with `//go:build go1.N` build constraints.
+The `go` directive now specifies a _minimum_ Go version for the module.
+Furthermore, it sets the language version that is in effect, which may change
+the semantics of Go code. For example, before Go 1.22, loop variables were
+reused across iterations, but since Go 1.22, loop variables only exist for the
+duration of an iteration. Modules that specify `go 1.22` will use the new
+semantics, while modules that specify an older version will not.
+
+Individual files can both upgrade and downgrade their language version by using
+`//go:build go1.N` directives. In a module that requires Go 1.22, a file
+specifying Go 1.21 will experience the old loop variable semantics, and vice
+versa. Because the Go module as a whole still specifies a minimum version, even
+files specifying an older version will have access to the standard library of
+the minimum version.
+
+Staticcheck 2024.1 takes all of this into consideration when analyzing the
+behavior of Go code, when determining which checks are applicable, and when
+making suggestions. Older versions of Staticcheck were already aware of Go
+versions, but 2024.1 works on a more fine-grained, per-file basis, and
+differentiates between the pre- and post-1.21 semantics of the `go` directive.
+
+The `-go` command line flag continues to exist. It will override any
+module-based version selection. This is primarily useful for Go modules that
+target older Go versions (because here, the `go` directive didn't specify a
+_minimum_ version), or when working outside of Go modules.
+
+To prevent misinterpreting code, Staticcheck now refuses to analyze modules that
+require a version of Go that is newer than that with which Staticcheck was
+built.
+
+## Checks
+
+### New checks
+
+The following checks have been added:
+
+- {{< check "SA1031" >}} flags overlapping destination and source slices passed
+  to certain encoding functions.
+- {{< check "SA1032" >}} flags calls to
+  [`errors.Is`](https://pkg.go.dev/errors#Is) where the two arguments have been
+  swapped.
+- {{< check "SA4032" >}} flags impossible comparisons of
+  [runtime.GOOS](https://pkg.go.dev/runtime#GOOS) and
+  [runtime.GOARCH](https://pkg.go.dev/runtime#GOARCH) based on the file's build
+  tags.
+- {{< check "SA6006" >}} flags `io.WriteString(w, string(b))` as it would be
+  both simpler and more efficient to use `w.Write(b)`.
+- {{< check "SA9009" >}} flags comments that look like they intend to be
+  compiler directives but which aren't due to extraneous whitespace.
+
+### Changed checks
+
+The following checks have been improved:
+
+- {{< check "QF1001" >}} no longer panics on expressions involving "key: value"
+  pairs ({{< issue "1484" >}}).
+- {{< check "S1008" >}} now understands that some built-in functions never
+  return negative values. For example, it now negates `len(x) > 0` as `len(x) ==
+  0` ({{< issue "1422" >}}).
+- {{< check "S1009" >}} now flags unnecessary nil checks that involve selector
+  expressions ({{< issue "1527" >}}).
+- {{< check "S1017" >}} no longer flags `if else` branches ({{< issue "1447"
+  >}}).
+- {{< check "SA1006" >}} now detects more Printf-like functions from the
+  standard library ({{< issue "1528" >}}).
+- {{< check "SA1015" >}} now skips any code targeting Go 1.23 or newer ({{<
+  issue "1558" >}}).
+- {{< check "SA1029" >}} now flags uses of the empty struct (`struct{}`) as
+  context keys ({{< issue "1504" >}}).
+- {{< check "SA4003" >}} now flags pointless integer comparisons that involve
+  literals, not just constants from the `math` package ({{< issue "1470" >}}).
+- {{< check "SA4015" >}} now supports conversions that involve generics.
+- {{< check "SA4023" >}} no longer panics on type sets that contain arrays ({{<
+  issue "1397" >}}).
+- {{< check "SA5001" >}} now emits a clearer message ({{< issue "1489" >}}).
+- {{< check "SA9003" >}} has been disabled by default because of too many noisy
+  positives ({{< issue "321" >}}).
+- {{< check "ST1000" >}} now permits punctuation following the package name, as
+  in "Package pkg, which ..." ({{< issue "1452" >}}).
+- {{< check "ST1018" >}} now accepts variation selectors in emoji and certain
+  Arabic formatting characters in string literals ({{< issue "1456" >}}).
+- {{< check "ST1020" >}} no longer flags comments that start with a deprecation
+  notice ({{< issue "1378" >}}).
+- {{< check "U1000" >}} handles generic interfaces slightly better, reducing the
+  number of false positives.
+- Due to improvements in the intermediate representation, various checks may now
+  detect more problems.
+
+## Miscellaneous changes and fixes
+
+- The `keyify` utility has been deleted. This functionality is provided by gopls
+  nowadays.
+- `staticcheck -merge` now exits with a non-zero exit status if any problems
+  were found. This matches the behavior of non-merge uses.
+- Malformed `staticcheck.conf` files now cause more useful errors to be emitted.
+- Labeled statements with blank labels no longer cause panics.
+- Functions with named return parameters that never actually return no longer
+  cause panics ({{< issue "1533" >}}).