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Auto merge of #118213 - Urgau:check-cfg-diagnostics-rustc-cargo, r=petrochenkov

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Add more suggestions to unexpected cfg names and values

This pull request adds more suggestion to unexpected cfg names and values diagnostics:
 - it first adds a links to the [rustc unstable book](https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html) or the [Cargo reference](https://doc.rust-lang.org/nightly/cargo/reference/unstable.html#check-cfg), depending if rustc is invoked by Cargo
 - it secondly adds a suggestion on how to expect the cfg name or value:
    *excluding well known names and values*
    - for Cargo: it suggest using a feature or `cargo:rust-check-cfg` in build script
    - for rustc: it suggest using `--check-cfg` (with the correct invocation)

Those diagnostics improvements are directed towards enabling users to fix the issue if the previous suggestions weren't good enough.

r? `@petrochenkov`
This commit is contained in:
bors 2023-12-13 19:45:57 +00:00
commit a90372c6e8
36 changed files with 468 additions and 326 deletions
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51
compiler/rustc_lint/src/context.rs
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@ -706,9 +706,13 @@ pub trait LintContext {
},
BuiltinLintDiagnostics::UnexpectedCfgName((name, name_span), value) => {
let possibilities: Vec<Symbol> = sess.parse_sess.check_config.expecteds.keys().copied().collect();
let is_from_cargo = std::env::var_os("CARGO").is_some();
let mut is_feature_cfg = name == sym::feature;
if is_feature_cfg && is_from_cargo {
db.help("consider defining some features in `Cargo.toml`");
// Suggest the most probable if we found one
if let Some(best_match) = find_best_match_for_name(&possibilities, name, None) {
} else if let Some(best_match) = find_best_match_for_name(&possibilities, name, None) {
if let Some(ExpectedValues::Some(best_match_values)) =
sess.parse_sess.check_config.expecteds.get(&best_match) {
let mut possibilities = best_match_values.iter()
@ -741,8 +745,8 @@ pub trait LintContext {
} else {
db.span_suggestion(name_span, "there is a config with a similar name", best_match, Applicability::MaybeIncorrect);
}
} else if name == sym::feature && std::env::var_os("CARGO").is_some() {
db.help("consider defining some features in `Cargo.toml`");
is_feature_cfg |= best_match == sym::feature;
} else if !possibilities.is_empty() {
let mut possibilities = possibilities.iter()
.map(Symbol::as_str)
@ -756,6 +760,23 @@ pub trait LintContext {
// once.
db.help_once(format!("expected names are: `{possibilities}`"));
}
let inst = if let Some((value, _value_span)) = value {
let pre = if is_from_cargo { "\\" } else { "" };
format!("cfg({name}, values({pre}\"{value}{pre}\"))")
} else {
format!("cfg({name})")
};
if is_from_cargo {
if !is_feature_cfg {
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}`"));
db.note("see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration");
}
},
BuiltinLintDiagnostics::UnexpectedCfgValue((name, name_span), value) => {
let Some(ExpectedValues::Some(values)) = &sess.parse_sess.check_config.expecteds.get(&name) else {
@ -767,6 +788,7 @@ pub trait LintContext {
.copied()
.flatten()
.collect();
let is_from_cargo = std::env::var_os("CARGO").is_some();
// Show the full list if all possible values for a given name, but don't do it
// for names as the possibilities could be very long
@ -787,6 +809,8 @@ pub trait LintContext {
db.span_suggestion(value_span, "there is a expected value with a similar name", format!("\"{best_match}\""), Applicability::MaybeIncorrect);
}
} else if name == sym::feature && is_from_cargo {
db.help(format!("consider defining `{name}` as feature in `Cargo.toml`"));
} else if let &[first_possibility] = &possibilities[..] {
db.span_suggestion(name_span.shrink_to_hi(), "specify a config value", format!(" = \"{first_possibility}\""), Applicability::MaybeIncorrect);
}
@ -796,6 +820,27 @@ pub trait LintContext {
db.span_suggestion(name_span.shrink_to_hi().to(value_span), "remove the value", "", Applicability::MaybeIncorrect);
}
}
let inst = if let Some((value, _value_span)) = value {
let pre = if is_from_cargo { "\\" } else { "" };
format!("cfg({name}, values({pre}\"{value}{pre}\"))")
} else {
format!("cfg({name})")
};
if is_from_cargo {
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(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}`"));
db.note("see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration");
}
},
BuiltinLintDiagnostics::DeprecatedWhereclauseLocation(new_span, suggestion) => {
db.multipart_suggestion(