Exclude well known names from showing a suggestion in check-cfg

Urgau · Urgau · commit 0883bfbc8ad1 · 2023-12-13T22:50:03.000+01:00
diff --git a/compiler/rustc_lint/src/context.rs b/compiler/rustc_lint/src/context.rs
@@ -821,6 +821,42 @@ pub trait LintContext {
                         }
                     }
 
+                    // We don't want to suggest adding values to well known names
+                    // since those are defined by rustc it-self. Users can still
+                    // do it if they want, but should not encourage them.
+                    const WELL_KNOWN_NAMES: &'static [Symbol] = &[
+                        // tidy-alphabetical-start
+                        sym::debug_assertions,
+                        sym::doc,
+                        sym::doctest,
+                        sym::miri,
+                        sym::overflow_checks,
+                        sym::panic,
+                        sym::proc_macro,
+                        sym::relocation_model,
+                        sym::sanitize,
+                        sym::sanitizer_cfi_generalize_pointers,
+                        sym::sanitizer_cfi_normalize_integers,
+                        sym::target_abi,
+                        sym::target_arch,
+                        sym::target_endian,
+                        sym::target_env,
+                        sym::target_family,
+                        sym::target_feature,
+                        sym::target_has_atomic,
+                        sym::target_has_atomic_equal_alignment,
+                        sym::target_has_atomic_load_store,
+                        sym::target_os,
+                        sym::target_pointer_width,
+                        sym::target_thread_local,
+                        sym::target_vendor,
+                        sym::test,
+                        sym::unix,
+                        sym::windows,
+                        // tidy-alphabetical-end
+                    ];
+
+                    let is_cfg_a_well_know_name = WELL_KNOWN_NAMES.contains(&name);
                     let inst = if let Some((value, _value_span)) = value {
                         let pre = if is_from_cargo { "\\" } else { "" };
                         format!("cfg({name}, values({pre}\"{value}{pre}\"))")
@@ -833,12 +869,14 @@ pub trait LintContext {
                             if let Some((value, _value_span)) = value {
                                 db.help(format!("consider adding `{value}` as a feature in `Cargo.toml`"));
                             }
-                        } else {
+                        } else if !is_cfg_a_well_know_name {
                             db.help(format!("consider using a Cargo feature instead or adding `println!(\"cargo:rustc-check-cfg={inst}\");` to the top of a `build.rs`"));
                         }
                         db.note("see <https://doc.rust-lang.org/nightly/cargo/reference/unstable.html#check-cfg> for more information about checking conditional configuration");
                     } else {
-                        db.help(format!("to expect this configuration use `--check-cfg={inst}`"));
+                        if !is_cfg_a_well_know_name {
+                            db.help(format!("to expect this configuration use `--check-cfg={inst}`"));
+                        }
                         db.note("see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration");
                     }
                 },
diff --git a/tests/ui/check-cfg/compact-values.stderr b/tests/ui/check-cfg/compact-values.stderr
@@ -5,7 +5,6 @@ LL | #[cfg(target(os = "linux", pointer_width = "X"))]
    |                            ^^^^^^^^^^^^^^^^^^^
    |
    = note: expected values for `target_pointer_width` are: `16`, `32`, `64`
-   = help: to expect this configuration use `--check-cfg=cfg(target_pointer_width, values("X"))`
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
    = note: `#[warn(unexpected_cfgs)]` on by default
 
diff --git a/tests/ui/check-cfg/exhaustive-names-values.empty_cfg.stderr b/tests/ui/check-cfg/exhaustive-names-values.empty_cfg.stderr
@@ -18,7 +18,6 @@ LL | #[cfg(test = "value")]
    |           help: remove the value
    |
    = note: no expected value for `test`
-   = help: to expect this configuration use `--check-cfg=cfg(test, values("value"))`
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition name: `feature`
diff --git a/tests/ui/check-cfg/exhaustive-names-values.feature.stderr b/tests/ui/check-cfg/exhaustive-names-values.feature.stderr
@@ -18,7 +18,6 @@ LL | #[cfg(test = "value")]
    |           help: remove the value
    |
    = note: no expected value for `test`
-   = help: to expect this configuration use `--check-cfg=cfg(test, values("value"))`
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `unk`
diff --git a/tests/ui/check-cfg/exhaustive-names-values.full.stderr b/tests/ui/check-cfg/exhaustive-names-values.full.stderr
@@ -18,7 +18,6 @@ LL | #[cfg(test = "value")]
    |           help: remove the value
    |
    = note: no expected value for `test`
-   = help: to expect this configuration use `--check-cfg=cfg(test, values("value"))`
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `unk`
diff --git a/tests/ui/check-cfg/exhaustive-values.empty_cfg.stderr b/tests/ui/check-cfg/exhaustive-values.empty_cfg.stderr
@@ -7,7 +7,6 @@ LL | #[cfg(test = "value")]
    |           help: remove the value
    |
    = note: no expected value for `test`
-   = help: to expect this configuration use `--check-cfg=cfg(test, values("value"))`
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
    = note: `#[warn(unexpected_cfgs)]` on by default
 
diff --git a/tests/ui/check-cfg/exhaustive-values.without_names.stderr b/tests/ui/check-cfg/exhaustive-values.without_names.stderr
@@ -7,7 +7,6 @@ LL | #[cfg(test = "value")]
    |           help: remove the value
    |
    = note: no expected value for `test`
-   = help: to expect this configuration use `--check-cfg=cfg(test, values("value"))`
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
    = note: `#[warn(unexpected_cfgs)]` on by default
 
diff --git a/tests/ui/check-cfg/no-expected-values.empty.stderr b/tests/ui/check-cfg/no-expected-values.empty.stderr
@@ -20,7 +20,6 @@ LL | #[cfg(test = "foo")]
    |           help: remove the value
    |
    = note: no expected value for `test`
-   = help: to expect this configuration use `--check-cfg=cfg(test, values("foo"))`
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: 2 warnings emitted
diff --git a/tests/ui/check-cfg/no-expected-values.mixed.stderr b/tests/ui/check-cfg/no-expected-values.mixed.stderr
@@ -20,7 +20,6 @@ LL | #[cfg(test = "foo")]
    |           help: remove the value
    |
    = note: no expected value for `test`
-   = help: to expect this configuration use `--check-cfg=cfg(test, values("foo"))`
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: 2 warnings emitted
diff --git a/tests/ui/check-cfg/no-expected-values.simple.stderr b/tests/ui/check-cfg/no-expected-values.simple.stderr
@@ -20,7 +20,6 @@ LL | #[cfg(test = "foo")]
    |           help: remove the value
    |
    = note: no expected value for `test`
-   = help: to expect this configuration use `--check-cfg=cfg(test, values("foo"))`
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: 2 warnings emitted
diff --git a/tests/ui/check-cfg/well-known-values.stderr b/tests/ui/check-cfg/well-known-values.stderr

Original file line number	Diff line number	Diff line change
`@@ -5,7 +5,6 @@ LL \| #[cfg(target(os = "linux", pointer_width = "X"))]`
`5`	`5`	`\| ^^^^^^^^^^^^^^^^^^^`
`6`	`6`	`\|`
`7`	`7`	= note: expected values for `target_pointer_width` are: `16`, `32`, `64`
`8`		- = help: to expect this configuration use `--check-cfg=cfg(target_pointer_width, values("X"))`
`9`	`8`	`= note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration`
`10`	`9`	= note: `#[warn(unexpected_cfgs)]` on by default
`11`	`10`
Original file line number	Diff line number	Diff line change
`@@ -18,7 +18,6 @@ LL \| #[cfg(test = "value")]`
`18`	`18`	`\| help: remove the value`
`19`	`19`	`\|`
`20`	`20`	= note: no expected value for `test`
`21`		- = help: to expect this configuration use `--check-cfg=cfg(test, values("value"))`
`22`	`21`	`= note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration`
`23`	`22`
`24`	`23`	warning: unexpected `cfg` condition name: `feature`
Original file line number	Diff line number	Diff line change
`@@ -7,7 +7,6 @@ LL \| #[cfg(test = "value")]`
`7`	`7`	`\| help: remove the value`
`8`	`8`	`\|`
`9`	`9`	= note: no expected value for `test`
`10`		- = help: to expect this configuration use `--check-cfg=cfg(test, values("value"))`
`11`	`10`	`= note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration`
`12`	`11`	= note: `#[warn(unexpected_cfgs)]` on by default
`13`	`12`
Original file line number	Diff line number	Diff line change
`@@ -20,7 +20,6 @@ LL \| #[cfg(test = "foo")]`
`20`	`20`	`\| help: remove the value`
`21`	`21`	`\|`
`22`	`22`	= note: no expected value for `test`
`23`		- = help: to expect this configuration use `--check-cfg=cfg(test, values("foo"))`
`24`	`23`	`= note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration`
`25`	`24`
`26`	`25`	`warning: 2 warnings emitted`