Add external macro specific diagnostic to check-cfg

Author: Urgau

compiler/rustc_lint/messages.ftl

@@ -803,10 +803,14 @@ lint_unexpected_cfg_add_build_rs_println = or consider adding `{$build_rs_printl
 lint_unexpected_cfg_add_cargo_feature = consider using a Cargo feature instead
 lint_unexpected_cfg_add_cargo_toml_lint_cfg = or consider adding in `Cargo.toml` the `check-cfg` lint config for the lint:{$cargo_toml_lint_cfg}
 lint_unexpected_cfg_add_cmdline_arg = to expect this configuration use `{$cmdline_arg}`
+lint_unexpected_cfg_cargo_update = the {$macro_kind} `{$macro_name}` may come from an old version of it's defining crate, try updating your dependencies with `cargo update`
+
 lint_unexpected_cfg_define_features = consider defining some features in `Cargo.toml`
 lint_unexpected_cfg_doc_cargo = see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
 lint_unexpected_cfg_doc_rustc = see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
 
+lint_unexpected_cfg_from_external_macro_origin = using a cfg inside a {$macro_kind} will use the cfgs from the destination crate and not the ones from the defining crate
+lint_unexpected_cfg_from_external_macro_refer = try refering to `{$macro_name}` crate for guidance on how handle this unexpected cfg
 lint_unexpected_cfg_name = unexpected `cfg` condition name: `{$name}`
 lint_unexpected_cfg_name_expected_names = expected names are: {$possibilities}{$and_more ->
         [0] {""}

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

@@ -1,9 +1,10 @@
+use rustc_hir::def_id::LOCAL_CRATE;
 use rustc_middle::bug;
 use rustc_session::Session;
 use rustc_session::config::ExpectedValues;
 use rustc_span::edit_distance::find_best_match_for_name;
 use rustc_span::symbol::Ident;
-use rustc_span::{Span, Symbol, sym};
+use rustc_span::{ExpnKind, Span, Symbol, sym};
 
 use crate::lints;
 
@@ -60,6 +61,35 @@ fn cargo_help_sub(
     }
 }
 
+fn rustc_macro_help(span: Span) -> Option<lints::UnexpectedCfgRustcMacroHelp> {
+    let oexpn = span.ctxt().outer_expn_data();
+    if let Some(def_id) = oexpn.macro_def_id
+        && let ExpnKind::Macro(macro_kind, macro_name) = oexpn.kind
+        && def_id.krate != LOCAL_CRATE
+    {
+        Some(lints::UnexpectedCfgRustcMacroHelp { macro_kind: macro_kind.descr(), macro_name })
+    } else {
+        None
+    }
+}
+
+fn cargo_macro_help(span: Span) -> Option<lints::UnexpectedCfgCargoMacroHelp> {
+    let oexpn = span.ctxt().outer_expn_data();
+    if let Some(def_id) = oexpn.macro_def_id
+        && let ExpnKind::Macro(macro_kind, macro_name) = oexpn.kind
+        && def_id.krate != LOCAL_CRATE
+    {
+        Some(lints::UnexpectedCfgCargoMacroHelp {
+            macro_kind: macro_kind.descr(),
+            macro_name,
+            // FIXME: Get access to a `TyCtxt` from an `EarlyContext`
+            // crate_name: cx.tcx.crate_name(def_id.krate),
+        })
+    } else {
+        None
+    }
+}
+
 pub(super) fn unexpected_cfg_name(
     sess: &Session,
     (name, name_span): (Symbol, Span),
@@ -186,16 +216,21 @@ pub(super) fn unexpected_cfg_name(
     };
 
     let invocation_help = if is_from_cargo {
-        let sub = if !is_feature_cfg && !is_from_external_macro {
+        let help = if !is_feature_cfg && !is_from_external_macro {
             Some(cargo_help_sub(sess, &inst))
         } else {
             None
         };
-        lints::unexpected_cfg_name::InvocationHelp::Cargo { sub }
+        lints::unexpected_cfg_name::InvocationHelp::Cargo {
+            help,
+            macro_help: cargo_macro_help(name_span),
+        }
     } else {
-        lints::unexpected_cfg_name::InvocationHelp::Rustc(lints::UnexpectedCfgRustcHelp::new(
-            &inst(EscapeQuotes::No),
-        ))
+        let help = lints::UnexpectedCfgRustcHelp::new(&inst(EscapeQuotes::No));
+        lints::unexpected_cfg_name::InvocationHelp::Rustc {
+            help,
+            macro_help: rustc_macro_help(name_span),
+        }
     };
 
     lints::UnexpectedCfgName { code_sugg, invocation_help, name }
@@ -302,14 +337,20 @@ pub(super) fn unexpected_cfg_value(
         } else {
             None
         };
-        lints::unexpected_cfg_value::InvocationHelp::Cargo(help)
+        lints::unexpected_cfg_value::InvocationHelp::Cargo {
+            help,
+            macro_help: cargo_macro_help(name_span),
+        }
     } else {
         let help = if can_suggest_adding_value {
             Some(lints::UnexpectedCfgRustcHelp::new(&inst(EscapeQuotes::No)))
         } else {
             None
         };
-        lints::unexpected_cfg_value::InvocationHelp::Rustc(help)
+        lints::unexpected_cfg_value::InvocationHelp::Rustc {
+            help,
+            macro_help: rustc_macro_help(name_span),
+        }
     };
 
     lints::UnexpectedCfgValue {

compiler/rustc_lint/src/lints.rs

@@ -2131,6 +2131,25 @@ impl UnexpectedCfgRustcHelp {
     }
 }
 
+#[derive(Subdiagnostic)]
+#[note(lint_unexpected_cfg_from_external_macro_origin)]
+#[help(lint_unexpected_cfg_from_external_macro_refer)]
+pub(crate) struct UnexpectedCfgRustcMacroHelp {
+    pub macro_kind: &'static str,
+    pub macro_name: Symbol,
+}
+
+#[derive(Subdiagnostic)]
+#[note(lint_unexpected_cfg_from_external_macro_origin)]
+#[help(lint_unexpected_cfg_from_external_macro_refer)]
+#[help(lint_unexpected_cfg_cargo_update)]
+pub(crate) struct UnexpectedCfgCargoMacroHelp {
+    pub macro_kind: &'static str,
+    pub macro_name: Symbol,
+    // FIXME: Figure out a way to get the crate name
+    // crate_name: String,
+}
+
 #[derive(LintDiagnostic)]
 #[diag(lint_unexpected_cfg_name)]
 pub(crate) struct UnexpectedCfgName {
@@ -2235,10 +2254,17 @@ pub(crate) mod unexpected_cfg_name {
         #[note(lint_unexpected_cfg_doc_cargo)]
         Cargo {
             #[subdiagnostic]
-            sub: Option<super::UnexpectedCfgCargoHelp>,
+            macro_help: Option<super::UnexpectedCfgCargoMacroHelp>,
+            #[subdiagnostic]
+            help: Option<super::UnexpectedCfgCargoHelp>,
         },
         #[note(lint_unexpected_cfg_doc_rustc)]
-        Rustc(#[subdiagnostic] super::UnexpectedCfgRustcHelp),
+        Rustc {
+            #[subdiagnostic]
+            macro_help: Option<super::UnexpectedCfgRustcMacroHelp>,
+            #[subdiagnostic]
+            help: super::UnexpectedCfgRustcHelp,
+        },
     }
 }
 
@@ -2341,9 +2367,19 @@ pub(crate) mod unexpected_cfg_value {
     #[derive(Subdiagnostic)]
     pub(crate) enum InvocationHelp {
         #[note(lint_unexpected_cfg_doc_cargo)]
-        Cargo(#[subdiagnostic] Option<CargoHelp>),
+        Cargo {
+            #[subdiagnostic]
+            help: Option<CargoHelp>,
+            #[subdiagnostic]
+            macro_help: Option<super::UnexpectedCfgCargoMacroHelp>,
+        },
         #[note(lint_unexpected_cfg_doc_rustc)]
-        Rustc(#[subdiagnostic] Option<super::UnexpectedCfgRustcHelp>),
+        Rustc {
+            #[subdiagnostic]
+            help: Option<super::UnexpectedCfgRustcHelp>,
+            #[subdiagnostic]
+            macro_help: Option<super::UnexpectedCfgRustcMacroHelp>,
+        },
     }
 
     #[derive(Subdiagnostic)]

tests/ui/check-cfg/report-in-external-macros.cargo.stderr

@@ -5,6 +5,9 @@ LL |     cfg_macro::my_lib_macro!();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: expected names are: `clippy`, `debug_assertions`, `doc`, `doctest`, `feature`, `fmt_debug`, `miri`, `overflow_checks`, `panic`, `proc_macro`, `relocation_model`, `rustfmt`, `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`, `ub_checks`, `unix`, and `windows`
+   = note: using a cfg inside a macro will use the cfgs from the destination crate and not the ones from the defining crate
+   = help: try refering to `cfg_macro::my_lib_macro` crate for guidance on how handle this unexpected cfg
+   = help: the macro `cfg_macro::my_lib_macro` may come from an old version of it's defining crate, try updating your dependencies with `cargo update`
    = 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
    = note: this warning originates in the macro `cfg_macro::my_lib_macro` (in Nightly builds, run with -Z macro-backtrace for more info)
@@ -16,6 +19,9 @@ LL |     cfg_macro::my_lib_macro_value!();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: expected values for `panic` are: `abort` and `unwind`
+   = note: using a cfg inside a macro will use the cfgs from the destination crate and not the ones from the defining crate
+   = help: try refering to `cfg_macro::my_lib_macro_value` crate for guidance on how handle this unexpected cfg
+   = help: the macro `cfg_macro::my_lib_macro_value` may come from an old version of it's defining crate, try updating your dependencies with `cargo update`
    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
    = note: this warning originates in the macro `cfg_macro::my_lib_macro_value` (in Nightly builds, run with -Z macro-backtrace for more info)
 
@@ -26,6 +32,9 @@ LL |     cfg_macro::my_lib_macro_feature!();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: no expected values for `feature`
+   = note: using a cfg inside a macro will use the cfgs from the destination crate and not the ones from the defining crate
+   = help: try refering to `cfg_macro::my_lib_macro_feature` crate for guidance on how handle this unexpected cfg
+   = help: the macro `cfg_macro::my_lib_macro_feature` may come from an old version of it's defining crate, try updating your dependencies with `cargo update`
    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
    = note: this warning originates in the macro `cfg_macro::my_lib_macro_feature` (in Nightly builds, run with -Z macro-backtrace for more info)
 

tests/ui/check-cfg/report-in-external-macros.rustc.stderr

@@ -5,6 +5,8 @@ LL |     cfg_macro::my_lib_macro!();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: expected names are: `clippy`, `debug_assertions`, `doc`, `doctest`, `feature`, `fmt_debug`, `miri`, `overflow_checks`, `panic`, `proc_macro`, `relocation_model`, `rustfmt`, `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`, `ub_checks`, `unix`, and `windows`
+   = note: using a cfg inside a macro will use the cfgs from the destination crate and not the ones from the defining crate
+   = help: try refering to `cfg_macro::my_lib_macro` crate for guidance on how handle this unexpected cfg
    = help: to expect this configuration use `--check-cfg=cfg(my_lib_cfg)`
    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
    = note: `#[warn(unexpected_cfgs)]` on by default
@@ -17,6 +19,8 @@ LL |     cfg_macro::my_lib_macro_value!();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: expected values for `panic` are: `abort` and `unwind`
+   = note: using a cfg inside a macro will use the cfgs from the destination crate and not the ones from the defining crate
+   = help: try refering to `cfg_macro::my_lib_macro_value` crate for guidance on how handle this unexpected cfg
    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
    = note: this warning originates in the macro `cfg_macro::my_lib_macro_value` (in Nightly builds, run with -Z macro-backtrace for more info)
 
@@ -28,6 +32,8 @@ LL |     cfg_macro::my_lib_macro_feature!();
    |
    = note: no expected values for `feature`
    = help: to expect this configuration use `--check-cfg=cfg(feature, values("UNEXPECTED_FEATURE"))`
+   = note: using a cfg inside a macro will use the cfgs from the destination crate and not the ones from the defining crate
+   = help: try refering to `cfg_macro::my_lib_macro_feature` crate for guidance on how handle this unexpected cfg
    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
    = note: this warning originates in the macro `cfg_macro::my_lib_macro_feature` (in Nightly builds, run with -Z macro-backtrace for more info)