Refer to the Cargo specific doc in the check-cfg diagnostics

compiler/rustc_lint/src/context/diagnostics/check_cfg.rs

@@ -182,11 +182,12 @@ pub(super) fn unexpected_cfg_name(
             diag.help(format!("or consider adding in `Cargo.toml` the `check-cfg` lint config for the lint:\n [lints.rust]\n unexpected_cfgs = {{ level = \"warn\", check-cfg = ['{}'] }}", inst(EscapeQuotes::No)));
             diag.help(format!("or consider adding `println!(\"cargo::rustc-check-cfg={}\");` to the top of the `build.rs`", inst(EscapeQuotes::Yes)));
         }
+        diag.note("see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration");
     } else {
         let inst = inst(EscapeQuotes::No);
         diag.help(format!("to expect this configuration use `--check-cfg={inst}`",));
+        diag.note("see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration");
     }
-    diag.note("see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration");
 }
 
 pub(super) fn unexpected_cfg_value(
@@ -281,11 +282,12 @@ pub(super) fn unexpected_cfg_value(
             diag.help(format!("or consider adding in `Cargo.toml` the `check-cfg` lint config for the lint:\n [lints.rust]\n unexpected_cfgs = {{ level = \"warn\", check-cfg = ['{}'] }}", inst(EscapeQuotes::No)));
             diag.help(format!("or consider adding `println!(\"cargo::rustc-check-cfg={}\");` to the top of the `build.rs`", inst(EscapeQuotes::Yes)));
         }
+        diag.note("see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration");
     } else {
         if !is_cfg_a_well_know_name {
             let inst = inst(EscapeQuotes::No);
             diag.help(format!("to expect this configuration use `--check-cfg={inst}`",));
         }
+        diag.note("see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration");
     }
-    diag.note("see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration");
 }

tests/ui/check-cfg/cargo-feature.none.stderr

@@ -6,7 +6,7 @@ LL | #[cfg(feature = "serde")]
    |
    = note: no expected values for `feature`
    = help: consider adding `serde` as a feature in `Cargo.toml`
-   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
+   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
    = note: `#[warn(unexpected_cfgs)]` on by default
 
 warning: unexpected `cfg` condition value: (none)
@@ -17,7 +17,7 @@ LL | #[cfg(feature)]
    |
    = note: no expected values for `feature`
    = help: consider defining some features in `Cargo.toml`
-   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
+   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition name: `tokio_unstable`
   --> $DIR/cargo-feature.rs:22:7
@@ -31,7 +31,7 @@ LL | #[cfg(tokio_unstable)]
             [lints.rust]
             unexpected_cfgs = { level = "warn", check-cfg = ['cfg(tokio_unstable)'] }
    = help: or consider adding `println!("cargo::rustc-check-cfg=cfg(tokio_unstable)");` to the top of the `build.rs`
-   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
+   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition name: `CONFIG_NVME`
   --> $DIR/cargo-feature.rs:26:7
@@ -44,7 +44,7 @@ LL | #[cfg(CONFIG_NVME = "m")]
             [lints.rust]
             unexpected_cfgs = { level = "warn", check-cfg = ['cfg(CONFIG_NVME, values("m"))'] }
    = help: or consider adding `println!("cargo::rustc-check-cfg=cfg(CONFIG_NVME, values(\"m\"))");` to the top of the `build.rs`
-   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
+   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
 
 warning: 4 warnings emitted
 

tests/ui/check-cfg/cargo-feature.some.stderr

@@ -6,7 +6,7 @@ LL | #[cfg(feature = "serde")]
    |
    = note: expected values for `feature` are: `bitcode`
    = help: consider adding `serde` as a feature in `Cargo.toml`
-   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
+   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
    = note: `#[warn(unexpected_cfgs)]` on by default
 
 warning: unexpected `cfg` condition value: (none)
@@ -17,7 +17,7 @@ LL | #[cfg(feature)]
    |
    = note: expected values for `feature` are: `bitcode`
    = help: consider defining some features in `Cargo.toml`
-   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
+   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition name: `tokio_unstable`
   --> $DIR/cargo-feature.rs:22:7
@@ -31,7 +31,7 @@ LL | #[cfg(tokio_unstable)]
             [lints.rust]
             unexpected_cfgs = { level = "warn", check-cfg = ['cfg(tokio_unstable)'] }
    = help: or consider adding `println!("cargo::rustc-check-cfg=cfg(tokio_unstable)");` to the top of the `build.rs`
-   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
+   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `m`
   --> $DIR/cargo-feature.rs:26:7
@@ -47,7 +47,7 @@ LL | #[cfg(CONFIG_NVME = "m")]
             [lints.rust]
             unexpected_cfgs = { level = "warn", check-cfg = ['cfg(CONFIG_NVME, values("m"))'] }
    = help: or consider adding `println!("cargo::rustc-check-cfg=cfg(CONFIG_NVME, values(\"m\"))");` to the top of the `build.rs`
-   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
+   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
 
 warning: 4 warnings emitted
 

tests/ui/check-cfg/diagnotics.cargo.stderr

@@ -5,7 +5,7 @@ LL | #[cfg(featur)]
    |       ^^^^^^ help: there is a config with a similar name: `feature`
    |
    = help: expected values for `feature` are: `foo`
-   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
+   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
    = note: `#[warn(unexpected_cfgs)]` on by default
 
 warning: unexpected `cfg` condition name: `featur`
@@ -14,7 +14,7 @@ warning: unexpected `cfg` condition name: `featur`
 LL | #[cfg(featur = "foo")]
    |       ^^^^^^^^^^^^^^
    |
-   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
+   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
 help: there is a config with a similar name and value
    |
 LL | #[cfg(feature = "foo")]
@@ -27,7 +27,7 @@ LL | #[cfg(featur = "fo")]
    |       ^^^^^^^^^^^^^
    |
    = help: expected values for `feature` are: `foo`
-   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
+   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
 help: there is a config with a similar name and different values
    |
 LL | #[cfg(feature = "foo")]
@@ -44,7 +44,7 @@ LL | #[cfg(no_value)]
             [lints.rust]
             unexpected_cfgs = { level = "warn", check-cfg = ['cfg(no_value)'] }
    = help: or consider adding `println!("cargo::rustc-check-cfg=cfg(no_value)");` to the top of the `build.rs`
-   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
+   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition name: `no_value`
   --> $DIR/diagnotics.rs:27:7
@@ -57,7 +57,7 @@ LL | #[cfg(no_value = "foo")]
             [lints.rust]
             unexpected_cfgs = { level = "warn", check-cfg = ['cfg(no_value, values("foo"))'] }
    = help: or consider adding `println!("cargo::rustc-check-cfg=cfg(no_value, values(\"foo\"))");` to the top of the `build.rs`
-   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
+   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
 help: there is a config with a similar name and no value
    |
 LL | #[cfg(no_values)]
@@ -77,7 +77,7 @@ LL | #[cfg(no_values = "bar")]
             [lints.rust]
             unexpected_cfgs = { level = "warn", check-cfg = ['cfg(no_values, values("bar"))'] }
    = help: or consider adding `println!("cargo::rustc-check-cfg=cfg(no_values, values(\"bar\"))");` to the top of the `build.rs`
-   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
+   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
 
 warning: 6 warnings emitted