diff --git a/compiler/rustc_interface/src/interface.rs b/compiler/rustc_interface/src/interface.rs index 32fba6ade88df..5ca8809099675 100644 --- a/compiler/rustc_interface/src/interface.rs +++ b/compiler/rustc_interface/src/interface.rs @@ -218,7 +218,9 @@ pub(crate) fn parse_check_cfg(dcx: &DiagCtxt, specs: Vec) -> CheckCfg { } } - if values.is_empty() && !values_any_specified && !any_specified { + if !values_specified && !any_specified { + // `cfg(name)` is equivalent to `cfg(name, values(none()))` so add + // an implicit `none()` values.insert(None); } else if !values.is_empty() && values_any_specified { error!( diff --git a/compiler/rustc_lint/src/context/diagnostics.rs b/compiler/rustc_lint/src/context/diagnostics.rs index 9e6a6f70eac07..312874db3f54e 100644 --- a/compiler/rustc_lint/src/context/diagnostics.rs +++ b/compiler/rustc_lint/src/context/diagnostics.rs @@ -354,6 +354,15 @@ pub(super) fn builtin( Applicability::MaybeIncorrect, ); } + } else { + db.note(format!("no expected values for `{name}`")); + + let sp = if let Some((_value, value_span)) = value { + name_span.to(value_span) + } else { + name_span + }; + db.span_suggestion(sp, "remove the condition", "", Applicability::MaybeIncorrect); } // We don't want to suggest adding values to well known names @@ -373,6 +382,8 @@ pub(super) fn builtin( if name == sym::feature { if let Some((value, _value_span)) = value { db.help(format!("consider adding `{value}` as a feature in `Cargo.toml`")); + } else { + db.help("consider defining some features in `Cargo.toml`"); } } 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`")); diff --git a/src/doc/unstable-book/src/compiler-flags/check-cfg.md b/src/doc/unstable-book/src/compiler-flags/check-cfg.md index 78bc8dceb7824..bf83f6ad7c5fb 100644 --- a/src/doc/unstable-book/src/compiler-flags/check-cfg.md +++ b/src/doc/unstable-book/src/compiler-flags/check-cfg.md @@ -44,15 +44,20 @@ To enable checking of values, but to provide an *none*/empty set of expected val ```bash rustc --check-cfg 'cfg(name)' -rustc --check-cfg 'cfg(name, values())' rustc --check-cfg 'cfg(name, values(none()))' ``` -To enable checking of name but not values (i.e. unknown expected values), use this form: +To enable checking of name but not values, use one of these forms: -```bash -rustc --check-cfg 'cfg(name, values(any()))' -``` + - No expected values (_will lint on every value_): + ```bash + rustc --check-cfg 'cfg(name, values())' + ``` + + - Unknown expected values (_will never lint_): + ```bash + rustc --check-cfg 'cfg(name, values(any()))' + ``` To avoid repeating the same set of values, use this form: @@ -114,18 +119,14 @@ as argument to `--check-cfg`. This table describe the equivalence of a `--cfg` argument to a `--check-cfg` argument. | `--cfg` | `--check-cfg` | -|-----------------------------|----------------------------------------------------------| +|-------------------------------|------------------------------------------------------------| | *nothing* | *nothing* or `--check-cfg=cfg()` (to enable the checking) | -| `--cfg foo` | `--check-cfg=cfg(foo), --check-cfg=cfg(foo, values())` or `--check-cfg=cfg(foo, values(none()))` | +| `--cfg foo` | `--check-cfg=cfg(foo)` or `--check-cfg=cfg(foo, values(none()))` | | `--cfg foo=""` | `--check-cfg=cfg(foo, values(""))` | | `--cfg foo="bar"` | `--check-cfg=cfg(foo, values("bar"))` | | `--cfg foo="1" --cfg foo="2"` | `--check-cfg=cfg(foo, values("1", "2"))` | | `--cfg foo="1" --cfg bar="2"` | `--check-cfg=cfg(foo, values("1")) --check-cfg=cfg(bar, values("2"))` | -| `--cfg foo --cfg foo="bar"` | `--check-cfg=cfg(foo) --check-cfg=cfg(foo, values("bar"))` | - -NOTE: There is (currently) no way to express that a condition name is expected but no (!= none) -values are expected. Passing an empty `values()` means *(none)* in the sense of `#[cfg(foo)]` -with no value. Users are expected to NOT pass a `--check-cfg` with that condition name. +| `--cfg foo --cfg foo="bar"` | `--check-cfg=cfg(foo, values(none(), "bar"))` | ### Example: Cargo-like `feature` example diff --git a/tests/ui/check-cfg/cargo-feature.none.stderr b/tests/ui/check-cfg/cargo-feature.none.stderr index 9a30842948478..aed4fd2a8c0e9 100644 --- a/tests/ui/check-cfg/cargo-feature.none.stderr +++ b/tests/ui/check-cfg/cargo-feature.none.stderr @@ -1,34 +1,36 @@ -warning: unexpected `cfg` condition name: `feature` - --> $DIR/cargo-feature.rs:13:7 +warning: unexpected `cfg` condition value: `serde` + --> $DIR/cargo-feature.rs:14:7 | LL | #[cfg(feature = "serde")] - | ^^^^^^^^^^^^^^^^^ + | ^^^^^^^^^^^^^^^^^ help: remove the condition | - = help: consider defining some features in `Cargo.toml` + = note: no expected values for `feature` + = help: consider adding `serde` as a feature in `Cargo.toml` = note: see for more information about checking conditional configuration = note: `#[warn(unexpected_cfgs)]` on by default -warning: unexpected `cfg` condition name: `feature` +warning: unexpected `cfg` condition value: (none) --> $DIR/cargo-feature.rs:18:7 | LL | #[cfg(feature)] - | ^^^^^^^ + | ^^^^^^^ help: remove the condition | + = note: no expected values for `feature` = help: consider defining some features in `Cargo.toml` = note: see for more information about checking conditional configuration warning: unexpected `cfg` condition name: `tokio_unstable` - --> $DIR/cargo-feature.rs:23:7 + --> $DIR/cargo-feature.rs:22:7 | LL | #[cfg(tokio_unstable)] | ^^^^^^^^^^^^^^ | - = help: expected names are: `debug_assertions`, `doc`, `doctest`, `miri`, `overflow_checks`, `panic`, `proc_macro`, `relocation_model`, `sanitize`, `sanitizer_cfi_generalize_pointers`, `sanitizer_cfi_normalize_integers`, `target_abi`, `target_arch`, `target_endian`, `target_env`, `target_family`, `target_feature`, `target_has_atomic`, `target_has_atomic_equal_alignment`, `target_has_atomic_load_store`, `target_os`, `target_pointer_width`, `target_thread_local`, `target_vendor`, `test`, `unix`, `windows` + = help: expected names are: `debug_assertions`, `doc`, `doctest`, `feature`, `miri`, `overflow_checks`, `panic`, `proc_macro`, `relocation_model`, `sanitize`, `sanitizer_cfi_generalize_pointers`, `sanitizer_cfi_normalize_integers`, `target_abi`, `target_arch`, `target_endian`, `target_env`, `target_family`, `target_feature`, `target_has_atomic`, `target_has_atomic_equal_alignment`, `target_has_atomic_load_store`, `target_os`, `target_pointer_width`, `target_thread_local`, `target_vendor`, `test`, `unix`, `windows` = help: consider using a Cargo feature instead or adding `println!("cargo:rustc-check-cfg=cfg(tokio_unstable)");` to the top of a `build.rs` = note: see for more information about checking conditional configuration warning: unexpected `cfg` condition name: `CONFIG_NVME` - --> $DIR/cargo-feature.rs:27:7 + --> $DIR/cargo-feature.rs:26:7 | LL | #[cfg(CONFIG_NVME = "m")] | ^^^^^^^^^^^^^^^^^ diff --git a/tests/ui/check-cfg/cargo-feature.rs b/tests/ui/check-cfg/cargo-feature.rs index f2fd0fd6420f6..8542174d0c099 100644 --- a/tests/ui/check-cfg/cargo-feature.rs +++ b/tests/ui/check-cfg/cargo-feature.rs @@ -5,19 +5,18 @@ // check-pass // revisions: some none // rustc-env:CARGO=/usr/bin/cargo -// compile-flags: --check-cfg=cfg() -Z unstable-options +// compile-flags: -Z unstable-options +// [none]compile-flags: --check-cfg=cfg(feature,values()) // [some]compile-flags: --check-cfg=cfg(feature,values("bitcode")) // [some]compile-flags: --check-cfg=cfg(CONFIG_NVME,values("y")) // [none]error-pattern:Cargo.toml #[cfg(feature = "serde")] -//[none]~^ WARNING unexpected `cfg` condition name -//[some]~^^ WARNING unexpected `cfg` condition value +//~^ WARNING unexpected `cfg` condition value fn ser() {} #[cfg(feature)] -//[none]~^ WARNING unexpected `cfg` condition name -//[some]~^^ WARNING unexpected `cfg` condition value +//~^ WARNING unexpected `cfg` condition value fn feat() {} #[cfg(tokio_unstable)] diff --git a/tests/ui/check-cfg/cargo-feature.some.stderr b/tests/ui/check-cfg/cargo-feature.some.stderr index fc6951b56174a..74d65e550bbe4 100644 --- a/tests/ui/check-cfg/cargo-feature.some.stderr +++ b/tests/ui/check-cfg/cargo-feature.some.stderr @@ -1,5 +1,5 @@ warning: unexpected `cfg` condition value: `serde` - --> $DIR/cargo-feature.rs:13:7 + --> $DIR/cargo-feature.rs:14:7 | LL | #[cfg(feature = "serde")] | ^^^^^^^^^^^^^^^^^ @@ -16,10 +16,11 @@ LL | #[cfg(feature)] | ^^^^^^^- help: specify a config value: `= "bitcode"` | = note: expected values for `feature` are: `bitcode` + = help: consider defining some features in `Cargo.toml` = note: see for more information about checking conditional configuration warning: unexpected `cfg` condition name: `tokio_unstable` - --> $DIR/cargo-feature.rs:23:7 + --> $DIR/cargo-feature.rs:22:7 | LL | #[cfg(tokio_unstable)] | ^^^^^^^^^^^^^^ @@ -29,7 +30,7 @@ LL | #[cfg(tokio_unstable)] = note: see for more information about checking conditional configuration warning: unexpected `cfg` condition value: `m` - --> $DIR/cargo-feature.rs:27:7 + --> $DIR/cargo-feature.rs:26:7 | LL | #[cfg(CONFIG_NVME = "m")] | ^^^^^^^^^^^^^^--- diff --git a/tests/ui/check-cfg/concat-values.rs b/tests/ui/check-cfg/concat-values.rs index 0f9178ce6a571..ad922f8c9088e 100644 --- a/tests/ui/check-cfg/concat-values.rs +++ b/tests/ui/check-cfg/concat-values.rs @@ -1,6 +1,7 @@ // check-pass // compile-flags: -Z unstable-options // compile-flags: --check-cfg=cfg(my_cfg,values("foo")) --check-cfg=cfg(my_cfg,values("bar")) +// compile-flags: --check-cfg=cfg(my_cfg,values()) #[cfg(my_cfg)] //~^ WARNING unexpected `cfg` condition value @@ -10,4 +11,7 @@ fn my_cfg() {} //~^ WARNING unexpected `cfg` condition value fn my_cfg() {} +#[cfg(any(my_cfg = "foo", my_cfg = "bar"))] +fn foo_and_bar() {} + fn main() {} diff --git a/tests/ui/check-cfg/concat-values.stderr b/tests/ui/check-cfg/concat-values.stderr index dec43f5bda3bc..6fe9f2baa09f4 100644 --- a/tests/ui/check-cfg/concat-values.stderr +++ b/tests/ui/check-cfg/concat-values.stderr @@ -1,5 +1,5 @@ warning: unexpected `cfg` condition value: (none) - --> $DIR/concat-values.rs:5:7 + --> $DIR/concat-values.rs:6:7 | LL | #[cfg(my_cfg)] | ^^^^^^ @@ -10,7 +10,7 @@ LL | #[cfg(my_cfg)] = note: `#[warn(unexpected_cfgs)]` on by default warning: unexpected `cfg` condition value: `unk` - --> $DIR/concat-values.rs:9:7 + --> $DIR/concat-values.rs:10:7 | LL | #[cfg(my_cfg = "unk")] | ^^^^^^^^^^^^^^ diff --git a/tests/ui/check-cfg/empty-values.rs b/tests/ui/check-cfg/empty-values.rs new file mode 100644 index 0000000000000..7e6ba6ae84a86 --- /dev/null +++ b/tests/ui/check-cfg/empty-values.rs @@ -0,0 +1,14 @@ +// Check that we detect unexpected value when none are allowed +// +// check-pass +// compile-flags: --check-cfg=cfg(foo,values()) -Zunstable-options + +#[cfg(foo = "foo")] +//~^ WARNING unexpected `cfg` condition value +fn do_foo() {} + +#[cfg(foo)] +//~^ WARNING unexpected `cfg` condition value +fn do_foo() {} + +fn main() {} diff --git a/tests/ui/check-cfg/empty-values.stderr b/tests/ui/check-cfg/empty-values.stderr new file mode 100644 index 0000000000000..e7b0b05d56168 --- /dev/null +++ b/tests/ui/check-cfg/empty-values.stderr @@ -0,0 +1,23 @@ +warning: unexpected `cfg` condition value: `foo` + --> $DIR/empty-values.rs:6:7 + | +LL | #[cfg(foo = "foo")] + | ^^^^^^^^^^^ help: remove the condition + | + = note: no expected values for `foo` + = help: to expect this configuration use `--check-cfg=cfg(foo, values("foo"))` + = note: see for more information about checking conditional configuration + = note: `#[warn(unexpected_cfgs)]` on by default + +warning: unexpected `cfg` condition value: (none) + --> $DIR/empty-values.rs:10:7 + | +LL | #[cfg(foo)] + | ^^^ help: remove the condition + | + = note: no expected values for `foo` + = help: to expect this configuration use `--check-cfg=cfg(foo)` + = note: see for more information about checking conditional configuration + +warning: 2 warnings emitted +