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Move around the code responsible for decorating builtin diagnostics

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This commit is contained in:
Urgau 2023-12-30 16:13:23 +01:00
parent d59f06fc64
commit 429287243b
2 changed files with 538 additions and 444 deletions
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450
compiler/rustc_lint/src/context.rs
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@ -18,34 +18,32 @@ use self::TargetLint::*;
use crate::levels::LintLevelsBuilder;
use crate::passes::{EarlyLintPassObject, LateLintPassObject};
use rustc_ast::util::unicode::TEXT_FLOW_CONTROL_CHARS;
use rustc_data_structures::fx::FxHashMap;
use rustc_data_structures::sync;
use rustc_errors::{add_elided_lifetime_in_path_suggestion, DiagnosticBuilder, DiagnosticMessage};
use rustc_errors::{Applicability, DecorateLint, MultiSpan, SuggestionStyle};
use rustc_errors::{DecorateLint, DiagnosticBuilder, DiagnosticMessage, MultiSpan};
use rustc_feature::Features;
use rustc_hir as hir;
use rustc_hir::def::Res;
use rustc_hir::def_id::{CrateNum, DefId};
use rustc_hir::definitions::{DefPathData, DisambiguatedDefPathData};
use rustc_middle::middle::privacy::EffectiveVisibilities;
use rustc_middle::middle::stability;
use rustc_middle::ty::layout::{LayoutError, LayoutOfHelpers, TyAndLayout};
use rustc_middle::ty::print::{with_no_trimmed_paths, PrintError};
use rustc_middle::ty::{self, print::Printer, GenericArg, RegisteredTools, Ty, TyCtxt};
use rustc_session::config::ExpectedValues;
use rustc_session::lint::{BuiltinLintDiagnostics, LintExpectationId};
use rustc_session::lint::{FutureIncompatibleInfo, Level, Lint, LintBuffer, LintId};
use rustc_session::{LintStoreMarker, Session};
use rustc_span::edit_distance::find_best_match_for_name;
use rustc_span::symbol::{sym, Ident, Symbol};
use rustc_span::{BytePos, Span};
use rustc_span::Span;
use rustc_target::abi;
use std::cell::Cell;
use std::iter;
use std::slice;
mod diagnostics;
type EarlyLintPassFactory = dyn Fn() -> EarlyLintPassObject + sync::DynSend + sync::DynSync;
type LateLintPassFactory =
dyn for<'tcx> Fn(TyCtxt<'tcx>) -> LateLintPassObject<'tcx> + sync::DynSend + sync::DynSync;
@ -531,445 +529,9 @@ pub trait LintContext {
diagnostic: BuiltinLintDiagnostics,
) {
// We first generate a blank diagnostic.
self.lookup(lint, span, msg,|db| {
self.lookup(lint, span, msg, |db| {
// Now, set up surrounding context.
let sess = self.sess();
match diagnostic {
BuiltinLintDiagnostics::UnicodeTextFlow(span, content) => {
let spans: Vec<_> = content
.char_indices()
.filter_map(|(i, c)| {
TEXT_FLOW_CONTROL_CHARS.contains(&c).then(|| {
let lo = span.lo() + BytePos(2 + i as u32);
(c, span.with_lo(lo).with_hi(lo + BytePos(c.len_utf8() as u32)))
})
})
.collect();
let (an, s) = match spans.len() {
1 => ("an ", ""),
_ => ("", "s"),
};
db.span_label(span, format!(
"this comment contains {an}invisible unicode text flow control codepoint{s}",
));
for (c, span) in &spans {
db.span_label(*span, format!("{c:?}"));
}
db.note(
"these kind of unicode codepoints change the way text flows on \
applications that support them, but can cause confusion because they \
change the order of characters on the screen",
);
if !spans.is_empty() {
db.multipart_suggestion_with_style(
"if their presence wasn't intentional, you can remove them",
spans.into_iter().map(|(_, span)| (span, "".to_string())).collect(),
Applicability::MachineApplicable,
SuggestionStyle::HideCodeAlways,
);
}
},
BuiltinLintDiagnostics::Normal => (),
BuiltinLintDiagnostics::AbsPathWithModule(span) => {
let (sugg, app) = match sess.source_map().span_to_snippet(span) {
Ok(ref s) => {
// FIXME(Manishearth) ideally the emitting code
// can tell us whether or not this is global
let opt_colon =
if s.trim_start().starts_with("::") { "" } else { "::" };
(format!("crate{opt_colon}{s}"), Applicability::MachineApplicable)
}
Err(_) => ("crate::<path>".to_string(), Applicability::HasPlaceholders),
};
db.span_suggestion(span, "use `crate`", sugg, app);
}
BuiltinLintDiagnostics::ProcMacroDeriveResolutionFallback(span) => {
db.span_label(
span,
"names from parent modules are not accessible without an explicit import",
);
}
BuiltinLintDiagnostics::MacroExpandedMacroExportsAccessedByAbsolutePaths(
span_def,
) => {
db.span_note(span_def, "the macro is defined here");
}
BuiltinLintDiagnostics::ElidedLifetimesInPaths(
n,
path_span,
incl_angl_brckt,
insertion_span,
) => {
add_elided_lifetime_in_path_suggestion(
sess.source_map(),
db,
n,
path_span,
incl_angl_brckt,
insertion_span,
);
}
BuiltinLintDiagnostics::UnknownCrateTypes(span, note, sugg) => {
db.span_suggestion(span, note, sugg, Applicability::MaybeIncorrect);
}
BuiltinLintDiagnostics::UnusedImports(message, replaces, in_test_module) => {
if !replaces.is_empty() {
db.tool_only_multipart_suggestion(
message,
replaces,
Applicability::MachineApplicable,
);
}
if let Some(span) = in_test_module {
db.span_help(
self.sess().source_map().guess_head_span(span),
"consider adding a `#[cfg(test)]` to the containing module",
);
}
}
BuiltinLintDiagnostics::RedundantImport(spans, ident) => {
for (span, is_imported) in spans {
let introduced = if is_imported { "imported" } else { "defined" };
db.span_label(
span,
format!("the item `{ident}` is already {introduced} here"),
);
}
}
BuiltinLintDiagnostics::DeprecatedMacro(suggestion, span) => {
stability::deprecation_suggestion(db, "macro", suggestion, span)
}
BuiltinLintDiagnostics::UnusedDocComment(span) => {
db.span_label(span, "rustdoc does not generate documentation for macro invocations");
db.help("to document an item produced by a macro, \
the macro must produce the documentation as part of its expansion");
}
BuiltinLintDiagnostics::PatternsInFnsWithoutBody(span, ident) => {
db.span_suggestion(span, "remove `mut` from the parameter", ident, Applicability::MachineApplicable);
}
BuiltinLintDiagnostics::MissingAbi(span, default_abi) => {
db.span_label(span, "ABI should be specified here");
db.help(format!("the default ABI is {}", default_abi.name()));
}
BuiltinLintDiagnostics::LegacyDeriveHelpers(span) => {
db.span_label(span, "the attribute is introduced here");
}
BuiltinLintDiagnostics::ProcMacroBackCompat(note) => {
db.note(note);
}
BuiltinLintDiagnostics::OrPatternsBackCompat(span,suggestion) => {
db.span_suggestion(span, "use pat_param to preserve semantics", suggestion, Applicability::MachineApplicable);
}
BuiltinLintDiagnostics::ReservedPrefix(span) => {
db.span_label(span, "unknown prefix");
db.span_suggestion_verbose(
span.shrink_to_hi(),
"insert whitespace here to avoid this being parsed as a prefix in Rust 2021",
" ",
Applicability::MachineApplicable,
);
}
BuiltinLintDiagnostics::UnusedBuiltinAttribute {
attr_name,
macro_name,
invoc_span
} => {
db.span_note(
invoc_span,
format!("the built-in attribute `{attr_name}` will be ignored, since it's applied to the macro invocation `{macro_name}`")
);
}
BuiltinLintDiagnostics::TrailingMacro(is_trailing, name) => {
if is_trailing {
db.note("macro invocations at the end of a block are treated as expressions");
db.note(format!("to ignore the value produced by the macro, add a semicolon after the invocation of `{name}`"));
}
}
BuiltinLintDiagnostics::BreakWithLabelAndLoop(span) => {
db.multipart_suggestion(
"wrap this expression in parentheses",
vec![(span.shrink_to_lo(), "(".to_string()),
(span.shrink_to_hi(), ")".to_string())],
Applicability::MachineApplicable
);
}
BuiltinLintDiagnostics::NamedAsmLabel(help) => {
db.help(help);
db.note("see the asm section of Rust By Example <https://doc.rust-lang.org/nightly/rust-by-example/unsafe/asm.html#labels> for more information");
},
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
} 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()
.flatten()
.map(Symbol::as_str)
.collect::<Vec<_>>();
possibilities.sort();
let mut should_print_possibilities = true;
if let Some((value, value_span)) = value {
if best_match_values.contains(&Some(value)) {
db.span_suggestion(name_span, "there is a config with a similar name and value", best_match, Applicability::MaybeIncorrect);
should_print_possibilities = false;
} else if best_match_values.contains(&None) {
db.span_suggestion(name_span.to(value_span), "there is a config with a similar name and no value", best_match, Applicability::MaybeIncorrect);
should_print_possibilities = false;
} else if let Some(first_value) = possibilities.first() {
db.span_suggestion(name_span.to(value_span), "there is a config with a similar name and different values", format!("{best_match} = \"{first_value}\""), Applicability::MaybeIncorrect);
} else {
db.span_suggestion(name_span.to(value_span), "there is a config with a similar name and different values", best_match, Applicability::MaybeIncorrect);
};
} else {
db.span_suggestion(name_span, "there is a config with a similar name", best_match, Applicability::MaybeIncorrect);
}
if !possibilities.is_empty() && should_print_possibilities {
let possibilities = possibilities.join("`, `");
db.help(format!("expected values for `{best_match}` are: `{possibilities}`"));
}
} else {
db.span_suggestion(name_span, "there is a config with a similar name", best_match, Applicability::MaybeIncorrect);
}
is_feature_cfg |= best_match == sym::feature;
} else if !possibilities.is_empty() {
let mut possibilities = possibilities.iter()
.map(Symbol::as_str)
.collect::<Vec<_>>();
possibilities.sort();
let possibilities = possibilities.join("`, `");
// The list of expected names can be long (even by default) and
// so the diagnostic produced can take a lot of space. To avoid
// cloging the user output we only want to print that diagnostic
// 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 {
bug!("it shouldn't be possible to have a diagnostic on a value whose name is not in values");
};
let mut have_none_possibility = false;
let possibilities: Vec<Symbol> = values.iter()
.inspect(|a| have_none_possibility |= a.is_none())
.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
if !possibilities.is_empty() {
{
let mut possibilities = possibilities.iter().map(Symbol::as_str).collect::<Vec<_>>();
possibilities.sort();
let possibilities = possibilities.join("`, `");
let none = if have_none_possibility { "(none), " } else { "" };
db.note(format!("expected values for `{name}` are: {none}`{possibilities}`"));
}
if let Some((value, value_span)) = value {
// Suggest the most probable if we found one
if let Some(best_match) = find_best_match_for_name(&possibilities, value, None) {
db.span_suggestion(value_span, "there is a expected value with a similar name", format!("\"{best_match}\""), Applicability::MaybeIncorrect);
}
} else if let &[first_possibility] = &possibilities[..] {
db.span_suggestion(name_span.shrink_to_hi(), "specify a config value", format!(" = \"{first_possibility}\""), Applicability::MaybeIncorrect);
}
} else if have_none_possibility {
db.note(format!("no expected value for `{name}`"));
if let Some((_value, value_span)) = value {
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(
"move it to the end of the type declaration",
vec![(db.span.primary_span().unwrap(), "".to_string()), (new_span, suggestion)],
Applicability::MachineApplicable,
);
db.note(
"see issue #89122 <https://github.com/rust-lang/rust/issues/89122> for more information",
);
},
BuiltinLintDiagnostics::SingleUseLifetime {
param_span,
use_span: Some((use_span, elide)),
deletion_span,
} => {
debug!(?param_span, ?use_span, ?deletion_span);
db.span_label(param_span, "this lifetime...");
db.span_label(use_span, "...is used only here");
if let Some(deletion_span) = deletion_span {
let msg = "elide the single-use lifetime";
let (use_span, replace_lt) = if elide {
let use_span = sess.source_map().span_extend_while(
use_span,
char::is_whitespace,
).unwrap_or(use_span);
(use_span, String::new())
} else {
(use_span, "'_".to_owned())
};
debug!(?deletion_span, ?use_span);
// issue 107998 for the case such as a wrong function pointer type
// `deletion_span` is empty and there is no need to report lifetime uses here
let suggestions = if deletion_span.is_empty() {
vec![(use_span, replace_lt)]
} else {
vec![(deletion_span, String::new()), (use_span, replace_lt)]
};
db.multipart_suggestion(
msg,
suggestions,
Applicability::MachineApplicable,
);
}
},
BuiltinLintDiagnostics::SingleUseLifetime {
param_span: _,
use_span: None,
deletion_span,
} => {
debug!(?deletion_span);
if let Some(deletion_span) = deletion_span {
db.span_suggestion(
deletion_span,
"elide the unused lifetime",
"",
Applicability::MachineApplicable,
);
}
},
BuiltinLintDiagnostics::NamedArgumentUsedPositionally{ position_sp_to_replace, position_sp_for_msg, named_arg_sp, named_arg_name, is_formatting_arg} => {
db.span_label(named_arg_sp, "this named argument is referred to by position in formatting string");
if let Some(positional_arg_for_msg) = position_sp_for_msg {
let msg = format!("this formatting argument uses named argument `{named_arg_name}` by position");
db.span_label(positional_arg_for_msg, msg);
}
if let Some(positional_arg_to_replace) = position_sp_to_replace {
let name = if is_formatting_arg { named_arg_name + "$" } else { named_arg_name };
let span_to_replace = if let Ok(positional_arg_content) =
self.sess().source_map().span_to_snippet(positional_arg_to_replace) && positional_arg_content.starts_with(':') {
positional_arg_to_replace.shrink_to_lo()
} else {
positional_arg_to_replace
};
db.span_suggestion_verbose(
span_to_replace,
"use the named argument by name to avoid ambiguity",
name,
Applicability::MaybeIncorrect,
);
}
}
BuiltinLintDiagnostics::ByteSliceInPackedStructWithDerive => {
db.help("consider implementing the trait by hand, or remove the `packed` attribute");
}
BuiltinLintDiagnostics::UnusedExternCrate { removal_span }=> {
db.span_suggestion(
removal_span,
"remove it",
"",
Applicability::MachineApplicable,
);
}
BuiltinLintDiagnostics::ExternCrateNotIdiomatic { vis_span, ident_span }=> {
let suggestion_span = vis_span.between(ident_span);
db.span_suggestion_verbose(
suggestion_span,
"convert it to a `use`",
if vis_span.is_empty() { "use " } else { " use " },
Applicability::MachineApplicable,
);
}
BuiltinLintDiagnostics::AmbiguousGlobImports { diag } => {
rustc_errors::report_ambiguity_error(db, diag);
}
BuiltinLintDiagnostics::AmbiguousGlobReexports { name, namespace, first_reexport_span, duplicate_reexport_span } => {
db.span_label(first_reexport_span, format!("the name `{name}` in the {namespace} namespace is first re-exported here"));
db.span_label(duplicate_reexport_span, format!("but the name `{name}` in the {namespace} namespace is also re-exported here"));
}
BuiltinLintDiagnostics::HiddenGlobReexports { name, namespace, glob_reexport_span, private_item_span } => {
db.span_note(glob_reexport_span, format!("the name `{name}` in the {namespace} namespace is supposed to be publicly re-exported here"));
db.span_note(private_item_span, "but the private item here shadows it".to_owned());
}
BuiltinLintDiagnostics::UnusedQualifications { removal_span } => {
db.span_suggestion_verbose(
removal_span,
"remove the unnecessary path segments",
"",
Applicability::MachineApplicable
);
}
BuiltinLintDiagnostics::AssociatedConstElidedLifetime { elided, span } => {
db.span_suggestion_verbose(
if elided { span.shrink_to_hi() } else { span },
"use the `'static` lifetime",
if elided { "'static " } else { "'static" },
Applicability::MachineApplicable
);
},
BuiltinLintDiagnostics::RedundantImportVisibility { max_vis, span } => {
db.span_note(span, format!("the most public imported item is `{max_vis}`"));
db.help("reduce the glob import's visibility or increase visibility of imported items");
}
}
diagnostics::builtin(self.sess(), diagnostic, db);
// Rewrap `db`, and pass control to the user.
decorate(db)
});

532
compiler/rustc_lint/src/context/diagnostics.rs Normal file
View File

@ -0,0 +1,532 @@
use rustc_ast::util::unicode::TEXT_FLOW_CONTROL_CHARS;
use rustc_errors::{add_elided_lifetime_in_path_suggestion, DiagnosticBuilder};
use rustc_errors::{Applicability, SuggestionStyle};
use rustc_middle::middle::stability;
use rustc_session::config::ExpectedValues;
use rustc_session::lint::BuiltinLintDiagnostics;
use rustc_session::Session;
use rustc_span::edit_distance::find_best_match_for_name;
use rustc_span::symbol::{sym, Symbol};
use rustc_span::BytePos;
pub(super) fn builtin(
sess: &Session,
diagnostic: BuiltinLintDiagnostics,
db: &mut DiagnosticBuilder<'_, ()>,
) {
match diagnostic {
BuiltinLintDiagnostics::UnicodeTextFlow(span, content) => {
let spans: Vec<_> = content
.char_indices()
.filter_map(|(i, c)| {
TEXT_FLOW_CONTROL_CHARS.contains(&c).then(|| {
let lo = span.lo() + BytePos(2 + i as u32);
(c, span.with_lo(lo).with_hi(lo + BytePos(c.len_utf8() as u32)))
})
})
.collect();
let (an, s) = match spans.len() {
1 => ("an ", ""),
_ => ("", "s"),
};
db.span_label(
span,
format!(
"this comment contains {an}invisible unicode text flow control codepoint{s}",
),
);
for (c, span) in &spans {
db.span_label(*span, format!("{c:?}"));
}
db.note(
"these kind of unicode codepoints change the way text flows on \
applications that support them, but can cause confusion because they \
change the order of characters on the screen",
);
if !spans.is_empty() {
db.multipart_suggestion_with_style(
"if their presence wasn't intentional, you can remove them",
spans.into_iter().map(|(_, span)| (span, "".to_string())).collect(),
Applicability::MachineApplicable,
SuggestionStyle::HideCodeAlways,
);
}
}
BuiltinLintDiagnostics::Normal => (),
BuiltinLintDiagnostics::AbsPathWithModule(span) => {
let (sugg, app) = match sess.source_map().span_to_snippet(span) {
Ok(ref s) => {
// FIXME(Manishearth) ideally the emitting code
// can tell us whether or not this is global
let opt_colon = if s.trim_start().starts_with("::") { "" } else { "::" };
(format!("crate{opt_colon}{s}"), Applicability::MachineApplicable)
}
Err(_) => ("crate::<path>".to_string(), Applicability::HasPlaceholders),
};
db.span_suggestion(span, "use `crate`", sugg, app);
}
BuiltinLintDiagnostics::ProcMacroDeriveResolutionFallback(span) => {
db.span_label(
span,
"names from parent modules are not accessible without an explicit import",
);
}
BuiltinLintDiagnostics::MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def) => {
db.span_note(span_def, "the macro is defined here");
}
BuiltinLintDiagnostics::ElidedLifetimesInPaths(
n,
path_span,
incl_angl_brckt,
insertion_span,
) => {
add_elided_lifetime_in_path_suggestion(
sess.source_map(),
db,
n,
path_span,
incl_angl_brckt,
insertion_span,
);
}
BuiltinLintDiagnostics::UnknownCrateTypes(span, note, sugg) => {
db.span_suggestion(span, note, sugg, Applicability::MaybeIncorrect);
}
BuiltinLintDiagnostics::UnusedImports(message, replaces, in_test_module) => {
if !replaces.is_empty() {
db.tool_only_multipart_suggestion(
message,
replaces,
Applicability::MachineApplicable,
);
}
if let Some(span) = in_test_module {
db.span_help(
sess.source_map().guess_head_span(span),
"consider adding a `#[cfg(test)]` to the containing module",
);
}
}
BuiltinLintDiagnostics::RedundantImport(spans, ident) => {
for (span, is_imported) in spans {
let introduced = if is_imported { "imported" } else { "defined" };
db.span_label(span, format!("the item `{ident}` is already {introduced} here"));
}
}
BuiltinLintDiagnostics::DeprecatedMacro(suggestion, span) => {
stability::deprecation_suggestion(db, "macro", suggestion, span)
}
BuiltinLintDiagnostics::UnusedDocComment(span) => {
db.span_label(span, "rustdoc does not generate documentation for macro invocations");
db.help("to document an item produced by a macro, \
the macro must produce the documentation as part of its expansion");
}
BuiltinLintDiagnostics::PatternsInFnsWithoutBody(span, ident) => {
db.span_suggestion(
span,
"remove `mut` from the parameter",
ident,
Applicability::MachineApplicable,
);
}
BuiltinLintDiagnostics::MissingAbi(span, default_abi) => {
db.span_label(span, "ABI should be specified here");
db.help(format!("the default ABI is {}", default_abi.name()));
}
BuiltinLintDiagnostics::LegacyDeriveHelpers(span) => {
db.span_label(span, "the attribute is introduced here");
}
BuiltinLintDiagnostics::ProcMacroBackCompat(note) => {
db.note(note);
}
BuiltinLintDiagnostics::OrPatternsBackCompat(span, suggestion) => {
db.span_suggestion(
span,
"use pat_param to preserve semantics",
suggestion,
Applicability::MachineApplicable,
);
}
BuiltinLintDiagnostics::ReservedPrefix(span) => {
db.span_label(span, "unknown prefix");
db.span_suggestion_verbose(
span.shrink_to_hi(),
"insert whitespace here to avoid this being parsed as a prefix in Rust 2021",
" ",
Applicability::MachineApplicable,
);
}
BuiltinLintDiagnostics::UnusedBuiltinAttribute { attr_name, macro_name, invoc_span } => {
db.span_note(
invoc_span,
format!("the built-in attribute `{attr_name}` will be ignored, since it's applied to the macro invocation `{macro_name}`")
);
}
BuiltinLintDiagnostics::TrailingMacro(is_trailing, name) => {
if is_trailing {
db.note("macro invocations at the end of a block are treated as expressions");
db.note(format!("to ignore the value produced by the macro, add a semicolon after the invocation of `{name}`"));
}
}
BuiltinLintDiagnostics::BreakWithLabelAndLoop(span) => {
db.multipart_suggestion(
"wrap this expression in parentheses",
vec![
(span.shrink_to_lo(), "(".to_string()),
(span.shrink_to_hi(), ")".to_string()),
],
Applicability::MachineApplicable,
);
}
BuiltinLintDiagnostics::NamedAsmLabel(help) => {
db.help(help);
db.note("see the asm section of Rust By Example <https://doc.rust-lang.org/nightly/rust-by-example/unsafe/asm.html#labels> for more information");
}
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
} 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().flatten().map(Symbol::as_str).collect::<Vec<_>>();
possibilities.sort();
let mut should_print_possibilities = true;
if let Some((value, value_span)) = value {
if best_match_values.contains(&Some(value)) {
db.span_suggestion(
name_span,
"there is a config with a similar name and value",
best_match,
Applicability::MaybeIncorrect,
);
should_print_possibilities = false;
} else if best_match_values.contains(&None) {
db.span_suggestion(
name_span.to(value_span),
"there is a config with a similar name and no value",
best_match,
Applicability::MaybeIncorrect,
);
should_print_possibilities = false;
} else if let Some(first_value) = possibilities.first() {
db.span_suggestion(
name_span.to(value_span),
"there is a config with a similar name and different values",
format!("{best_match} = \"{first_value}\""),
Applicability::MaybeIncorrect,
);
} else {
db.span_suggestion(
name_span.to(value_span),
"there is a config with a similar name and different values",
best_match,
Applicability::MaybeIncorrect,
);
};
} else {
db.span_suggestion(
name_span,
"there is a config with a similar name",
best_match,
Applicability::MaybeIncorrect,
);
}
if !possibilities.is_empty() && should_print_possibilities {
let possibilities = possibilities.join("`, `");
db.help(format!(
"expected values for `{best_match}` are: `{possibilities}`"
));
}
} else {
db.span_suggestion(
name_span,
"there is a config with a similar name",
best_match,
Applicability::MaybeIncorrect,
);
}
is_feature_cfg |= best_match == sym::feature;
} else if !possibilities.is_empty() {
let mut possibilities =
possibilities.iter().map(Symbol::as_str).collect::<Vec<_>>();
possibilities.sort();
let possibilities = possibilities.join("`, `");
// The list of expected names can be long (even by default) and
// so the diagnostic produced can take a lot of space. To avoid
// cloging the user output we only want to print that diagnostic
// 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 {
bug!(
"it shouldn't be possible to have a diagnostic on a value whose name is not in values"
);
};
let mut have_none_possibility = false;
let possibilities: Vec<Symbol> = values
.iter()
.inspect(|a| have_none_possibility |= a.is_none())
.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
if !possibilities.is_empty() {
{
let mut possibilities =
possibilities.iter().map(Symbol::as_str).collect::<Vec<_>>();
possibilities.sort();
let possibilities = possibilities.join("`, `");
let none = if have_none_possibility { "(none), " } else { "" };
db.note(format!("expected values for `{name}` are: {none}`{possibilities}`"));
}
if let Some((value, value_span)) = value {
// Suggest the most probable if we found one
if let Some(best_match) = find_best_match_for_name(&possibilities, value, None)
{
db.span_suggestion(
value_span,
"there is a expected value with a similar name",
format!("\"{best_match}\""),
Applicability::MaybeIncorrect,
);
}
} else if let &[first_possibility] = &possibilities[..] {
db.span_suggestion(
name_span.shrink_to_hi(),
"specify a config value",
format!(" = \"{first_possibility}\""),
Applicability::MaybeIncorrect,
);
}
} else if have_none_possibility {
db.note(format!("no expected value for `{name}`"));
if let Some((_value, value_span)) = value {
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(
"move it to the end of the type declaration",
vec![(db.span.primary_span().unwrap(), "".to_string()), (new_span, suggestion)],
Applicability::MachineApplicable,
);
db.note(
"see issue #89122 <https://github.com/rust-lang/rust/issues/89122> for more information",
);
}
BuiltinLintDiagnostics::SingleUseLifetime {
param_span,
use_span: Some((use_span, elide)),
deletion_span,
} => {
debug!(?param_span, ?use_span, ?deletion_span);
db.span_label(param_span, "this lifetime...");
db.span_label(use_span, "...is used only here");
if let Some(deletion_span) = deletion_span {
let msg = "elide the single-use lifetime";
let (use_span, replace_lt) = if elide {
let use_span = sess
.source_map()
.span_extend_while(use_span, char::is_whitespace)
.unwrap_or(use_span);
(use_span, String::new())
} else {
(use_span, "'_".to_owned())
};
debug!(?deletion_span, ?use_span);
// issue 107998 for the case such as a wrong function pointer type
// `deletion_span` is empty and there is no need to report lifetime uses here
let suggestions = if deletion_span.is_empty() {
vec![(use_span, replace_lt)]
} else {
vec![(deletion_span, String::new()), (use_span, replace_lt)]
};
db.multipart_suggestion(msg, suggestions, Applicability::MachineApplicable);
}
}
BuiltinLintDiagnostics::SingleUseLifetime {
param_span: _,
use_span: None,
deletion_span,
} => {
debug!(?deletion_span);
if let Some(deletion_span) = deletion_span {
db.span_suggestion(
deletion_span,
"elide the unused lifetime",
"",
Applicability::MachineApplicable,
);
}
}
BuiltinLintDiagnostics::NamedArgumentUsedPositionally {
position_sp_to_replace,
position_sp_for_msg,
named_arg_sp,
named_arg_name,
is_formatting_arg,
} => {
db.span_label(
named_arg_sp,
"this named argument is referred to by position in formatting string",
);
if let Some(positional_arg_for_msg) = position_sp_for_msg {
let msg = format!(
"this formatting argument uses named argument `{named_arg_name}` by position"
);
db.span_label(positional_arg_for_msg, msg);
}
if let Some(positional_arg_to_replace) = position_sp_to_replace {
let name = if is_formatting_arg { named_arg_name + "$" } else { named_arg_name };
let span_to_replace = if let Ok(positional_arg_content) =
sess.source_map().span_to_snippet(positional_arg_to_replace)
&& positional_arg_content.starts_with(':')
{
positional_arg_to_replace.shrink_to_lo()
} else {
positional_arg_to_replace
};
db.span_suggestion_verbose(
span_to_replace,
"use the named argument by name to avoid ambiguity",
name,
Applicability::MaybeIncorrect,
);
}
}
BuiltinLintDiagnostics::ByteSliceInPackedStructWithDerive => {
db.help("consider implementing the trait by hand, or remove the `packed` attribute");
}
BuiltinLintDiagnostics::UnusedExternCrate { removal_span } => {
db.span_suggestion(removal_span, "remove it", "", Applicability::MachineApplicable);
}
BuiltinLintDiagnostics::ExternCrateNotIdiomatic { vis_span, ident_span } => {
let suggestion_span = vis_span.between(ident_span);
db.span_suggestion_verbose(
suggestion_span,
"convert it to a `use`",
if vis_span.is_empty() { "use " } else { " use " },
Applicability::MachineApplicable,
);
}
BuiltinLintDiagnostics::AmbiguousGlobImports { diag } => {
rustc_errors::report_ambiguity_error(db, diag);
}
BuiltinLintDiagnostics::AmbiguousGlobReexports {
name,
namespace,
first_reexport_span,
duplicate_reexport_span,
} => {
db.span_label(
first_reexport_span,
format!("the name `{name}` in the {namespace} namespace is first re-exported here"),
);
db.span_label(
duplicate_reexport_span,
format!(
"but the name `{name}` in the {namespace} namespace is also re-exported here"
),
);
}
BuiltinLintDiagnostics::HiddenGlobReexports {
name,
namespace,
glob_reexport_span,
private_item_span,
} => {
db.span_note(glob_reexport_span, format!("the name `{name}` in the {namespace} namespace is supposed to be publicly re-exported here"));
db.span_note(private_item_span, "but the private item here shadows it".to_owned());
}
BuiltinLintDiagnostics::UnusedQualifications { removal_span } => {
db.span_suggestion_verbose(
removal_span,
"remove the unnecessary path segments",
"",
Applicability::MachineApplicable,
);
}
BuiltinLintDiagnostics::AssociatedConstElidedLifetime { elided, span } => {
db.span_suggestion_verbose(
if elided { span.shrink_to_hi() } else { span },
"use the `'static` lifetime",
if elided { "'static " } else { "'static" },
Applicability::MachineApplicable,
);
}
BuiltinLintDiagnostics::RedundantImportVisibility { max_vis, span } => {
db.span_note(span, format!("the most public imported item is `{max_vis}`"));
db.help("reduce the glob import's visibility or increase visibility of imported items");
}
}
}