configuration option to lint incompatible_msrv in test code (rust-lang#14279)

fixes rust-lang#14277

changelog: [`incompatible_msrv`]: add config option
[`check-incompatible-msrv-in-tests`] to enable in `#[test]` and
`#[cfg(test)]` code.

Author: blyxyas

CHANGELOG.md

@@ -6343,6 +6343,7 @@ Released 2018-09-13
 [`avoid-breaking-exported-api`]: https://doc.rust-lang.org/clippy/lint_configuration.html#avoid-breaking-exported-api
 [`await-holding-invalid-types`]: https://doc.rust-lang.org/clippy/lint_configuration.html#await-holding-invalid-types
 [`cargo-ignore-publish`]: https://doc.rust-lang.org/clippy/lint_configuration.html#cargo-ignore-publish
+[`check-incompatible-msrv-in-tests`]: https://doc.rust-lang.org/clippy/lint_configuration.html#check-incompatible-msrv-in-tests
 [`check-private-items`]: https://doc.rust-lang.org/clippy/lint_configuration.html#check-private-items
 [`cognitive-complexity-threshold`]: https://doc.rust-lang.org/clippy/lint_configuration.html#cognitive-complexity-threshold
 [`disallowed-macros`]: https://doc.rust-lang.org/clippy/lint_configuration.html#disallowed-macros

book/src/lint_configuration.md

@@ -415,6 +415,16 @@ For internal testing only, ignores the current `publish` settings in the Cargo m
 * [`cargo_common_metadata`](https://rust-lang.github.io/rust-clippy/master/index.html#cargo_common_metadata)
 
 
+## `check-incompatible-msrv-in-tests`
+Whether to check MSRV compatibility in `#[test]` and `#[cfg(test)]` code.
+
+**Default Value:** `false`
+
+---
+**Affected lints:**
+* [`incompatible_msrv`](https://rust-lang.github.io/rust-clippy/master/index.html#incompatible_msrv)
+
+
 ## `check-private-items`
 Whether to also run the listed lints on private items.
 

clippy_config/src/conf.rs

@@ -464,6 +464,9 @@ define_Conf! {
     /// For internal testing only, ignores the current `publish` settings in the Cargo manifest.
     #[lints(cargo_common_metadata)]
     cargo_ignore_publish: bool = false,
+    /// Whether to check MSRV compatibility in `#[test]` and `#[cfg(test)]` code.
+    #[lints(incompatible_msrv)]
+    check_incompatible_msrv_in_tests: bool = false,
     /// Whether to also run the listed lints on private items.
     #[lints(missing_errors_doc, missing_panics_doc, missing_safety_doc, unnecessary_safety_doc)]
     check_private_items: bool = false,

clippy_lints/src/incompatible_msrv.rs

@@ -42,6 +42,7 @@ declare_clippy_lint! {
 pub struct IncompatibleMsrv {
     msrv: Msrv,
     is_above_msrv: FxHashMap<DefId, RustcVersion>,
+    check_in_tests: bool,
 }
 
 impl_lint_pass!(IncompatibleMsrv => [INCOMPATIBLE_MSRV]);
@@ -51,6 +52,7 @@ impl IncompatibleMsrv {
         Self {
             msrv: conf.msrv.clone(),
             is_above_msrv: FxHashMap::default(),
+            check_in_tests: conf.check_incompatible_msrv_in_tests,
         }
     }
 
@@ -87,7 +89,7 @@ impl IncompatibleMsrv {
             return;
         }
         let version = self.get_def_id_version(cx.tcx, def_id);
-        if self.msrv.meets(version) || is_in_test(cx.tcx, node) {
+        if self.msrv.meets(version) || (!self.check_in_tests && is_in_test(cx.tcx, node)) {
             return;
         }
         if let ExpnKind::AstPass(_) | ExpnKind::Desugaring(_) = span.ctxt().outer_expn_data().kind {

tests/ui-toml/check_incompatible_msrv_in_tests/check_incompatible_msrv_in_tests.default.stderr

@@ -0,0 +1,11 @@
+error: current MSRV (Minimum Supported Rust Version) is `1.3.0` but this item is stable since `1.4.0`
+  --> tests/ui-toml/check_incompatible_msrv_in_tests/check_incompatible_msrv_in_tests.rs:14:5
+   |
+LL |     sleep(Duration::new(1, 0))
+   |     ^^^^^
+   |
+   = note: `-D clippy::incompatible-msrv` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::incompatible_msrv)]`
+
+error: aborting due to 1 previous error
+

tests/ui-toml/check_incompatible_msrv_in_tests/check_incompatible_msrv_in_tests.enabled.stderr

@@ -0,0 +1,23 @@
+error: current MSRV (Minimum Supported Rust Version) is `1.3.0` but this item is stable since `1.4.0`
+  --> tests/ui-toml/check_incompatible_msrv_in_tests/check_incompatible_msrv_in_tests.rs:14:5
+   |
+LL |     sleep(Duration::new(1, 0))
+   |     ^^^^^
+   |
+   = note: `-D clippy::incompatible-msrv` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::incompatible_msrv)]`
+
+error: current MSRV (Minimum Supported Rust Version) is `1.3.0` but this item is stable since `1.4.0`
+  --> tests/ui-toml/check_incompatible_msrv_in_tests/check_incompatible_msrv_in_tests.rs:20:5
+   |
+LL |     sleep(Duration::new(1, 0));
+   |     ^^^^^
+
+error: current MSRV (Minimum Supported Rust Version) is `1.3.0` but this item is stable since `1.4.0`
+  --> tests/ui-toml/check_incompatible_msrv_in_tests/check_incompatible_msrv_in_tests.rs:28:9
+   |
+LL |         sleep(Duration::new(1, 0));
+   |         ^^^^^
+
+error: aborting due to 3 previous errors
+

tests/ui-toml/check_incompatible_msrv_in_tests/check_incompatible_msrv_in_tests.rs

@@ -0,0 +1,31 @@
+//@compile-flags: --test
+//@revisions: default enabled
+//@[enabled] rustc-env:CLIPPY_CONF_DIR=tests/ui-toml/check_incompatible_msrv_in_tests/enabled
+//@[default] rustc-env:CLIPPY_CONF_DIR=tests/ui-toml/check_incompatible_msrv_in_tests/default
+
+#![warn(clippy::incompatible_msrv)]
+#![feature(custom_inner_attributes)]
+#![clippy::msrv = "1.3.0"]
+
+use std::thread::sleep;
+use std::time::Duration;
+
+fn main() {
+    sleep(Duration::new(1, 0))
+    //~^ incompatible_msrv
+}
+
+#[test]
+fn test() {
+    sleep(Duration::new(1, 0));
+    //~[enabled]^ incompatible_msrv
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    fn helper() {
+        sleep(Duration::new(1, 0));
+        //~[enabled]^ incompatible_msrv
+    }
+}

tests/ui-toml/check_incompatible_msrv_in_tests/default/clippy.toml

@@ -0,0 +1 @@
+# default config has check-incompatible-msrv-in-tests as false

tests/ui-toml/check_incompatible_msrv_in_tests/enabled/clippy.toml

@@ -0,0 +1 @@
+check-incompatible-msrv-in-tests = true

tests/ui-toml/toml_unknown_key/conf_unknown_key.stderr

@@ -31,6 +31,7 @@ error: error reading Clippy's configuration file: unknown field `foobar`, expect
            await-holding-invalid-types
            blacklisted-names
            cargo-ignore-publish
+           check-incompatible-msrv-in-tests
            check-private-items
            cognitive-complexity-threshold
            cyclomatic-complexity-threshold
@@ -122,6 +123,7 @@ error: error reading Clippy's configuration file: unknown field `barfoo`, expect
            await-holding-invalid-types
            blacklisted-names
            cargo-ignore-publish
+           check-incompatible-msrv-in-tests
            check-private-items
            cognitive-complexity-threshold
            cyclomatic-complexity-threshold
@@ -213,6 +215,7 @@ error: error reading Clippy's configuration file: unknown field `allow_mixed_uni
            await-holding-invalid-types
            blacklisted-names
            cargo-ignore-publish
+           check-incompatible-msrv-in-tests
            check-private-items
            cognitive-complexity-threshold
            cyclomatic-complexity-threshold