Unrolled build for rust-lang#117522

Rollup merge of rust-lang#117522 - Urgau:check-cfg-cli-own-lint, r=petrochenkov

Remove `--check-cfg` checking of command line `--cfg` args

Back in rust-lang#100574 we added to the `unexpected_cfgs` lint the checking of `--cfg` CLI arguments and emitted unexpected names and values for them.

The implementation works as expected, but it's usability in particular when using it in combination with Cargo+`RUSTFLAGS` as people who set `RUSTFLAGS=--cfg=tokio_unstable` (or whatever) have `unexpected_cfgs` warnings on all of their crates is debatable. ~~To fix this issue this PR proposes that we split the CLI argument checking into it's own separate allow-by-default lint: `unexpected_cli_cfgs`.~~

~~This has the advantage of letting people who want CLI warnings have them (although not by default anymore), while still linting on every unexpected cfg name and values in the code.~~

After some discussion with the Cargo team ([Zulip thread](https://rust-lang.zulipchat.com/#narrow/stream/246057-t-cargo/topic/check-cfg.20and.20RUSTFLAGS.20interaction)) and member of the compiler team (see below), I propose that we follow the suggestion from `@epage:` never check `--cfg` arguments, but still reserve us the possibility to do it later.

We would still lint on unexpected cfgs found in the source code no matter the `--cfg` args passed. This mean reverting rust-lang#100574 but NOT rust-lang#99519.

r? `@petrochenkov`

Author: rust-timer

compiler/rustc_lint/messages.ftl

@@ -128,12 +128,6 @@ lint_builtin_type_alias_generic_bounds = bounds on generic parameters are not en
 lint_builtin_type_alias_where_clause = where clauses are not enforced in type aliases
     .suggestion = the clause will not be checked when the type alias is used, and should be removed
 
-lint_builtin_unexpected_cli_config_name = unexpected `{$name}` as condition name
-    .help = was set with `--cfg` but isn't in the `--check-cfg` expected names
-
-lint_builtin_unexpected_cli_config_value = unexpected condition value `{$value}` for condition name `{$name}`
-    .help = was set with `--cfg` but isn't in the `--check-cfg` expected values
-
 lint_builtin_unpermitted_type_init_label = this code causes undefined behavior when executed
 lint_builtin_unpermitted_type_init_label_suggestion = help: use `MaybeUninit<T>` instead, and only call `assume_init` after initialization is done
 

compiler/rustc_lint/src/builtin.rs

@@ -33,7 +33,6 @@ use crate::{
         BuiltinMutablesTransmutes, BuiltinNoMangleGeneric, BuiltinNonShorthandFieldPatterns,
         BuiltinSpecialModuleNameUsed, BuiltinTrivialBounds, BuiltinTypeAliasGenericBounds,
         BuiltinTypeAliasGenericBoundsSuggestion, BuiltinTypeAliasWhereClause,
-        BuiltinUnexpectedCliConfigName, BuiltinUnexpectedCliConfigValue,
         BuiltinUngatedAsyncFnTrackCaller, BuiltinUnpermittedTypeInit,
         BuiltinUnpermittedTypeInitSub, BuiltinUnreachablePub, BuiltinUnsafe,
         BuiltinUnstableFeatures, BuiltinUnusedDocComment, BuiltinUnusedDocCommentSub,
@@ -60,7 +59,6 @@ use rustc_middle::ty::GenericArgKind;
 use rustc_middle::ty::ToPredicate;
 use rustc_middle::ty::TypeVisitableExt;
 use rustc_middle::ty::{self, Ty, TyCtxt, VariantDef};
-use rustc_session::config::ExpectedValues;
 use rustc_session::lint::{BuiltinLintDiagnostics, FutureIncompatibilityReason};
 use rustc_span::edition::Edition;
 use rustc_span::source_map::Spanned;
@@ -2889,26 +2887,3 @@ impl EarlyLintPass for SpecialModuleName {
         }
     }
 }
-
-pub use rustc_session::lint::builtin::UNEXPECTED_CFGS;
-
-declare_lint_pass!(UnexpectedCfgs => [UNEXPECTED_CFGS]);
-
-impl EarlyLintPass for UnexpectedCfgs {
-    fn check_crate(&mut self, cx: &EarlyContext<'_>, _: &ast::Crate) {
-        let cfg = &cx.sess().parse_sess.config;
-        let check_cfg = &cx.sess().parse_sess.check_config;
-        for &(name, value) in cfg {
-            match check_cfg.expecteds.get(&name) {
-                Some(ExpectedValues::Some(values)) if !values.contains(&value) => {
-                    let value = value.unwrap_or(kw::Empty);
-                    cx.emit_lint(UNEXPECTED_CFGS, BuiltinUnexpectedCliConfigValue { name, value });
-                }
-                None if check_cfg.exhaustive_names => {
-                    cx.emit_lint(UNEXPECTED_CFGS, BuiltinUnexpectedCliConfigName { name });
-                }
-                _ => { /* expected */ }
-            }
-        }
-    }
-}

compiler/rustc_lint/src/lib.rs

@@ -179,7 +179,6 @@ early_lint_methods!(
             IncompleteInternalFeatures: IncompleteInternalFeatures,
             RedundantSemicolons: RedundantSemicolons,
             UnusedDocComment: UnusedDocComment,
-            UnexpectedCfgs: UnexpectedCfgs,
         ]
     ]
 );

compiler/rustc_lint/src/lints.rs

@@ -553,21 +553,6 @@ pub enum BuiltinSpecialModuleNameUsed {
     Main,
 }
 
-#[derive(LintDiagnostic)]
-#[diag(lint_builtin_unexpected_cli_config_name)]
-#[help]
-pub struct BuiltinUnexpectedCliConfigName {
-    pub name: Symbol,
-}
-
-#[derive(LintDiagnostic)]
-#[diag(lint_builtin_unexpected_cli_config_value)]
-#[help]
-pub struct BuiltinUnexpectedCliConfigValue {
-    pub name: Symbol,
-    pub value: Symbol,
-}
-
 // deref_into_dyn_supertrait.rs
 #[derive(LintDiagnostic)]
 #[diag(lint_supertrait_as_deref_target)]

compiler/rustc_lint_defs/src/builtin.rs

@@ -3439,6 +3439,7 @@ declare_lint_pass! {
         UNCONDITIONAL_PANIC,
         UNCONDITIONAL_RECURSION,
         UNDEFINED_NAKED_FUNCTION_ABI,
+        UNEXPECTED_CFGS,
         UNFULFILLED_LINT_EXPECTATIONS,
         UNINHABITED_STATIC,
         UNKNOWN_CRATE_TYPES,

src/doc/unstable-book/src/compiler-flags/check-cfg.md

@@ -35,6 +35,9 @@ and `cfg!(name = "value")` call. It will check that the `"value"` specified is p
 list of expected values. If `"value"` is not in it, then `rustc` will report an `unexpected_cfgs`
 lint diagnostic. The default diagnostic level for this lint is `Warn`.
 
+The command line `--cfg` arguments are currently *NOT* checked but may very well be checked in
+the future.
+
 To enable checking of values, but to provide an empty set of expected values, use these forms:
 
 ```bash

tests/ui/check-cfg/exhaustive-names-values.empty_cfg.stderr

@@ -1,5 +1,5 @@
 warning: unexpected `cfg` condition name: `unknown_key`
-  --> $DIR/exhaustive-names-values.rs:12:7
+  --> $DIR/exhaustive-names-values.rs:11:7
    |
 LL | #[cfg(unknown_key = "value")]
    |       ^^^^^^^^^^^^^^^^^^^^^
@@ -8,7 +8,7 @@ LL | #[cfg(unknown_key = "value")]
    = note: `#[warn(unexpected_cfgs)]` on by default
 
 warning: unexpected `cfg` condition value: `value`
-  --> $DIR/exhaustive-names-values.rs:16:7
+  --> $DIR/exhaustive-names-values.rs:15:7
    |
 LL | #[cfg(test = "value")]
    |       ^^^^----------
@@ -17,9 +17,5 @@ LL | #[cfg(test = "value")]
    |
    = note: no expected value for `test`
 
-warning: unexpected `empty_cfg` as condition name
-   |
-   = help: was set with `--cfg` but isn't in the `--check-cfg` expected names
-
-warning: 3 warnings emitted
+warning: 2 warnings emitted
 

tests/ui/check-cfg/exhaustive-names-values.empty_names_values.stderr

@@ -1,5 +1,5 @@
 warning: unexpected `cfg` condition name: `unknown_key`
-  --> $DIR/exhaustive-names-values.rs:12:7
+  --> $DIR/exhaustive-names-values.rs:11:7
    |
 LL | #[cfg(unknown_key = "value")]
    |       ^^^^^^^^^^^^^^^^^^^^^
@@ -8,7 +8,7 @@ LL | #[cfg(unknown_key = "value")]
    = note: `#[warn(unexpected_cfgs)]` on by default
 
 warning: unexpected `cfg` condition value: `value`
-  --> $DIR/exhaustive-names-values.rs:16:7
+  --> $DIR/exhaustive-names-values.rs:15:7
    |
 LL | #[cfg(test = "value")]
    |       ^^^^----------
@@ -17,9 +17,5 @@ LL | #[cfg(test = "value")]
    |
    = note: no expected value for `test`
 
-warning: unexpected `empty_names_values` as condition name
-   |
-   = help: was set with `--cfg` but isn't in the `--check-cfg` expected names
-
-warning: 3 warnings emitted
+warning: 2 warnings emitted
 

tests/ui/check-cfg/exhaustive-names-values.feature.stderr

@@ -1,5 +1,5 @@
 warning: unexpected `cfg` condition name: `unknown_key`
-  --> $DIR/exhaustive-names-values.rs:12:7
+  --> $DIR/exhaustive-names-values.rs:11:7
    |
 LL | #[cfg(unknown_key = "value")]
    |       ^^^^^^^^^^^^^^^^^^^^^
@@ -8,7 +8,7 @@ LL | #[cfg(unknown_key = "value")]
    = note: `#[warn(unexpected_cfgs)]` on by default
 
 warning: unexpected `cfg` condition value: `value`
-  --> $DIR/exhaustive-names-values.rs:16:7
+  --> $DIR/exhaustive-names-values.rs:15:7
    |
 LL | #[cfg(test = "value")]
    |       ^^^^----------
@@ -18,16 +18,12 @@ LL | #[cfg(test = "value")]
    = note: no expected value for `test`
 
 warning: unexpected `cfg` condition value: `unk`
-  --> $DIR/exhaustive-names-values.rs:20:7
+  --> $DIR/exhaustive-names-values.rs:19:7
    |
 LL | #[cfg(feature = "unk")]
    |       ^^^^^^^^^^^^^^^
    |
    = note: expected values for `feature` are: `std`
 
-warning: unexpected condition value `` for condition name `feature`
-   |
-   = help: was set with `--cfg` but isn't in the `--check-cfg` expected values
-
-warning: 4 warnings emitted
+warning: 3 warnings emitted
 

tests/ui/check-cfg/exhaustive-names-values.full.stderr

@@ -1,5 +1,5 @@
 warning: unexpected `cfg` condition name: `unknown_key`
-  --> $DIR/exhaustive-names-values.rs:12:7
+  --> $DIR/exhaustive-names-values.rs:11:7
    |
 LL | #[cfg(unknown_key = "value")]
    |       ^^^^^^^^^^^^^^^^^^^^^
@@ -8,7 +8,7 @@ LL | #[cfg(unknown_key = "value")]
    = note: `#[warn(unexpected_cfgs)]` on by default
 
 warning: unexpected `cfg` condition value: `value`
-  --> $DIR/exhaustive-names-values.rs:16:7
+  --> $DIR/exhaustive-names-values.rs:15:7
    |
 LL | #[cfg(test = "value")]
    |       ^^^^----------
@@ -18,16 +18,12 @@ LL | #[cfg(test = "value")]
    = note: no expected value for `test`
 
 warning: unexpected `cfg` condition value: `unk`
-  --> $DIR/exhaustive-names-values.rs:20:7
+  --> $DIR/exhaustive-names-values.rs:19:7
    |
 LL | #[cfg(feature = "unk")]
    |       ^^^^^^^^^^^^^^^
    |
    = note: expected values for `feature` are: `std`
 
-warning: unexpected `full` as condition name
-   |
-   = help: was set with `--cfg` but isn't in the `--check-cfg` expected names
-
-warning: 4 warnings emitted
+warning: 3 warnings emitted