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Diffstat (limited to 'compiler/rustc_lint/src/context.rs')
| -rw-r--r-- | compiler/rustc_lint/src/context.rs | 1259 |
1 files changed, 1259 insertions, 0 deletions
diff --git a/compiler/rustc_lint/src/context.rs b/compiler/rustc_lint/src/context.rs new file mode 100644 index 000000000..b95fc341d --- /dev/null +++ b/compiler/rustc_lint/src/context.rs @@ -0,0 +1,1259 @@ +//! Implementation of lint checking. +//! +//! The lint checking is mostly consolidated into one pass which runs +//! after all other analyses. Throughout compilation, lint warnings +//! can be added via the `add_lint` method on the Session structure. This +//! requires a span and an ID of the node that the lint is being added to. The +//! lint isn't actually emitted at that time because it is unknown what the +//! actual lint level at that location is. +//! +//! To actually emit lint warnings/errors, a separate pass is used. +//! A context keeps track of the current state of all lint levels. +//! Upon entering a node of the ast which can modify the lint settings, the +//! previous lint state is pushed onto a stack and the ast is then recursed +//! upon. As the ast is traversed, this keeps track of the current lint level +//! for all lint attributes. + +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, struct_span_err}; +use rustc_errors::{ + Applicability, DecorateLint, LintDiagnosticBuilder, MultiSpan, SuggestionStyle, +}; +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::AccessLevels; +use rustc_middle::middle::stability; +use rustc_middle::ty::layout::{LayoutError, LayoutOfHelpers, TyAndLayout}; +use rustc_middle::ty::print::with_no_trimmed_paths; +use rustc_middle::ty::{self, print::Printer, subst::GenericArg, RegisteredTools, Ty, TyCtxt}; +use rustc_session::lint::{BuiltinLintDiagnostics, LintExpectationId}; +use rustc_session::lint::{FutureIncompatibleInfo, Level, Lint, LintBuffer, LintId}; +use rustc_session::Session; +use rustc_span::lev_distance::find_best_match_for_name; +use rustc_span::symbol::{sym, Ident, Symbol}; +use rustc_span::{BytePos, Span, DUMMY_SP}; +use rustc_target::abi; +use tracing::debug; + +use std::cell::Cell; +use std::iter; +use std::slice; + +/// Information about the registered lints. +/// +/// This is basically the subset of `Context` that we can +/// build early in the compile pipeline. +pub struct LintStore { + /// Registered lints. + lints: Vec<&'static Lint>, + + /// Constructor functions for each variety of lint pass. + /// + /// These should only be called once, but since we want to avoid locks or + /// interior mutability, we don't enforce this (and lints should, in theory, + /// be compatible with being constructed more than once, though not + /// necessarily in a sane manner. This is safe though.) + pub pre_expansion_passes: Vec<Box<dyn Fn() -> EarlyLintPassObject + sync::Send + sync::Sync>>, + pub early_passes: Vec<Box<dyn Fn() -> EarlyLintPassObject + sync::Send + sync::Sync>>, + pub late_passes: Vec<Box<dyn Fn() -> LateLintPassObject + sync::Send + sync::Sync>>, + /// This is unique in that we construct them per-module, so not once. + pub late_module_passes: Vec<Box<dyn Fn() -> LateLintPassObject + sync::Send + sync::Sync>>, + + /// Lints indexed by name. + by_name: FxHashMap<String, TargetLint>, + + /// Map of registered lint groups to what lints they expand to. + lint_groups: FxHashMap<&'static str, LintGroup>, +} + +/// The target of the `by_name` map, which accounts for renaming/deprecation. +#[derive(Debug)] +enum TargetLint { + /// A direct lint target + Id(LintId), + + /// Temporary renaming, used for easing migration pain; see #16545 + Renamed(String, LintId), + + /// Lint with this name existed previously, but has been removed/deprecated. + /// The string argument is the reason for removal. + Removed(String), + + /// A lint name that should give no warnings and have no effect. + /// + /// This is used by rustc to avoid warning about old rustdoc lints before rustdoc registers them as tool lints. + Ignored, +} + +pub enum FindLintError { + NotFound, + Removed, +} + +struct LintAlias { + name: &'static str, + /// Whether deprecation warnings should be suppressed for this alias. + silent: bool, +} + +struct LintGroup { + lint_ids: Vec<LintId>, + from_plugin: bool, + depr: Option<LintAlias>, +} + +#[derive(Debug)] +pub enum CheckLintNameResult<'a> { + Ok(&'a [LintId]), + /// Lint doesn't exist. Potentially contains a suggestion for a correct lint name. + NoLint(Option<Symbol>), + /// The lint refers to a tool that has not been registered. + NoTool, + /// The lint is either renamed or removed. This is the warning + /// message, and an optional new name (`None` if removed). + Warning(String, Option<String>), + /// The lint is from a tool. If the Option is None, then either + /// the lint does not exist in the tool or the code was not + /// compiled with the tool and therefore the lint was never + /// added to the `LintStore`. Otherwise the `LintId` will be + /// returned as if it where a rustc lint. + Tool(Result<&'a [LintId], (Option<&'a [LintId]>, String)>), +} + +impl LintStore { + pub fn new() -> LintStore { + LintStore { + lints: vec![], + pre_expansion_passes: vec![], + early_passes: vec![], + late_passes: vec![], + late_module_passes: vec![], + by_name: Default::default(), + lint_groups: Default::default(), + } + } + + pub fn get_lints<'t>(&'t self) -> &'t [&'static Lint] { + &self.lints + } + + pub fn get_lint_groups<'t>( + &'t self, + ) -> impl Iterator<Item = (&'static str, Vec<LintId>, bool)> + 't { + // This function is not used in a way which observes the order of lints. + #[allow(rustc::potential_query_instability)] + self.lint_groups + .iter() + .filter(|(_, LintGroup { depr, .. })| { + // Don't display deprecated lint groups. + depr.is_none() + }) + .map(|(k, LintGroup { lint_ids, from_plugin, .. })| { + (*k, lint_ids.clone(), *from_plugin) + }) + } + + pub fn register_early_pass( + &mut self, + pass: impl Fn() -> EarlyLintPassObject + 'static + sync::Send + sync::Sync, + ) { + self.early_passes.push(Box::new(pass)); + } + + /// This lint pass is softly deprecated. It misses expanded code and has caused a few + /// errors in the past. Currently, it is only used in Clippy. New implementations + /// should avoid using this interface, as it might be removed in the future. + /// + /// * See [rust#69838](https://github.com/rust-lang/rust/pull/69838) + /// * See [rust-clippy#5518](https://github.com/rust-lang/rust-clippy/pull/5518) + pub fn register_pre_expansion_pass( + &mut self, + pass: impl Fn() -> EarlyLintPassObject + 'static + sync::Send + sync::Sync, + ) { + self.pre_expansion_passes.push(Box::new(pass)); + } + + pub fn register_late_pass( + &mut self, + pass: impl Fn() -> LateLintPassObject + 'static + sync::Send + sync::Sync, + ) { + self.late_passes.push(Box::new(pass)); + } + + pub fn register_late_mod_pass( + &mut self, + pass: impl Fn() -> LateLintPassObject + 'static + sync::Send + sync::Sync, + ) { + self.late_module_passes.push(Box::new(pass)); + } + + // Helper method for register_early/late_pass + pub fn register_lints(&mut self, lints: &[&'static Lint]) { + for lint in lints { + self.lints.push(lint); + + let id = LintId::of(lint); + if self.by_name.insert(lint.name_lower(), Id(id)).is_some() { + bug!("duplicate specification of lint {}", lint.name_lower()) + } + + if let Some(FutureIncompatibleInfo { reason, .. }) = lint.future_incompatible { + if let Some(edition) = reason.edition() { + self.lint_groups + .entry(edition.lint_name()) + .or_insert(LintGroup { + lint_ids: vec![], + from_plugin: lint.is_plugin, + depr: None, + }) + .lint_ids + .push(id); + } else { + // Lints belonging to the `future_incompatible` lint group are lints where a + // future version of rustc will cause existing code to stop compiling. + // Lints tied to an edition don't count because they are opt-in. + self.lint_groups + .entry("future_incompatible") + .or_insert(LintGroup { + lint_ids: vec![], + from_plugin: lint.is_plugin, + depr: None, + }) + .lint_ids + .push(id); + } + } + } + } + + pub fn register_group_alias(&mut self, lint_name: &'static str, alias: &'static str) { + self.lint_groups.insert( + alias, + LintGroup { + lint_ids: vec![], + from_plugin: false, + depr: Some(LintAlias { name: lint_name, silent: true }), + }, + ); + } + + pub fn register_group( + &mut self, + from_plugin: bool, + name: &'static str, + deprecated_name: Option<&'static str>, + to: Vec<LintId>, + ) { + let new = self + .lint_groups + .insert(name, LintGroup { lint_ids: to, from_plugin, depr: None }) + .is_none(); + if let Some(deprecated) = deprecated_name { + self.lint_groups.insert( + deprecated, + LintGroup { + lint_ids: vec![], + from_plugin, + depr: Some(LintAlias { name, silent: false }), + }, + ); + } + + if !new { + bug!("duplicate specification of lint group {}", name); + } + } + + /// This lint should give no warning and have no effect. + /// + /// This is used by rustc to avoid warning about old rustdoc lints before rustdoc registers them as tool lints. + #[track_caller] + pub fn register_ignored(&mut self, name: &str) { + if self.by_name.insert(name.to_string(), Ignored).is_some() { + bug!("duplicate specification of lint {}", name); + } + } + + /// This lint has been renamed; warn about using the new name and apply the lint. + #[track_caller] + pub fn register_renamed(&mut self, old_name: &str, new_name: &str) { + let Some(&Id(target)) = self.by_name.get(new_name) else { + bug!("invalid lint renaming of {} to {}", old_name, new_name); + }; + self.by_name.insert(old_name.to_string(), Renamed(new_name.to_string(), target)); + } + + pub fn register_removed(&mut self, name: &str, reason: &str) { + self.by_name.insert(name.into(), Removed(reason.into())); + } + + pub fn find_lints(&self, mut lint_name: &str) -> Result<Vec<LintId>, FindLintError> { + match self.by_name.get(lint_name) { + Some(&Id(lint_id)) => Ok(vec![lint_id]), + Some(&Renamed(_, lint_id)) => Ok(vec![lint_id]), + Some(&Removed(_)) => Err(FindLintError::Removed), + Some(&Ignored) => Ok(vec![]), + None => loop { + return match self.lint_groups.get(lint_name) { + Some(LintGroup { lint_ids, depr, .. }) => { + if let Some(LintAlias { name, .. }) = depr { + lint_name = name; + continue; + } + Ok(lint_ids.clone()) + } + None => Err(FindLintError::Removed), + }; + }, + } + } + + /// Checks the validity of lint names derived from the command line. + pub fn check_lint_name_cmdline( + &self, + sess: &Session, + lint_name: &str, + level: Level, + registered_tools: &RegisteredTools, + ) { + let (tool_name, lint_name_only) = parse_lint_and_tool_name(lint_name); + if lint_name_only == crate::WARNINGS.name_lower() && matches!(level, Level::ForceWarn(_)) { + struct_span_err!( + sess, + DUMMY_SP, + E0602, + "`{}` lint group is not supported with ´--force-warn´", + crate::WARNINGS.name_lower() + ) + .emit(); + return; + } + let db = match self.check_lint_name(lint_name_only, tool_name, registered_tools) { + CheckLintNameResult::Ok(_) => None, + CheckLintNameResult::Warning(ref msg, _) => Some(sess.struct_warn(msg)), + CheckLintNameResult::NoLint(suggestion) => { + let mut err = + struct_span_err!(sess, DUMMY_SP, E0602, "unknown lint: `{}`", lint_name); + + if let Some(suggestion) = suggestion { + err.help(&format!("did you mean: `{}`", suggestion)); + } + + Some(err.forget_guarantee()) + } + CheckLintNameResult::Tool(result) => match result { + Err((Some(_), new_name)) => Some(sess.struct_warn(&format!( + "lint name `{}` is deprecated \ + and does not have an effect anymore. \ + Use: {}", + lint_name, new_name + ))), + _ => None, + }, + CheckLintNameResult::NoTool => Some( + struct_span_err!( + sess, + DUMMY_SP, + E0602, + "unknown lint tool: `{}`", + tool_name.unwrap() + ) + .forget_guarantee(), + ), + }; + + if let Some(mut db) = db { + let msg = format!( + "requested on the command line with `{} {}`", + match level { + Level::Allow => "-A", + Level::Warn => "-W", + Level::ForceWarn(_) => "--force-warn", + Level::Deny => "-D", + Level::Forbid => "-F", + Level::Expect(_) => { + unreachable!("lints with the level of `expect` should not run this code"); + } + }, + lint_name + ); + db.note(&msg); + db.emit(); + } + } + + /// True if this symbol represents a lint group name. + pub fn is_lint_group(&self, lint_name: Symbol) -> bool { + debug!( + "is_lint_group(lint_name={:?}, lint_groups={:?})", + lint_name, + self.lint_groups.keys().collect::<Vec<_>>() + ); + let lint_name_str = lint_name.as_str(); + self.lint_groups.contains_key(lint_name_str) || { + let warnings_name_str = crate::WARNINGS.name_lower(); + lint_name_str == warnings_name_str + } + } + + /// Checks the name of a lint for its existence, and whether it was + /// renamed or removed. Generates a DiagnosticBuilder containing a + /// warning for renamed and removed lints. This is over both lint + /// names from attributes and those passed on the command line. Since + /// it emits non-fatal warnings and there are *two* lint passes that + /// inspect attributes, this is only run from the late pass to avoid + /// printing duplicate warnings. + pub fn check_lint_name( + &self, + lint_name: &str, + tool_name: Option<Symbol>, + registered_tools: &RegisteredTools, + ) -> CheckLintNameResult<'_> { + if let Some(tool_name) = tool_name { + // FIXME: rustc and rustdoc are considered tools for lints, but not for attributes. + if tool_name != sym::rustc + && tool_name != sym::rustdoc + && !registered_tools.contains(&Ident::with_dummy_span(tool_name)) + { + return CheckLintNameResult::NoTool; + } + } + + let complete_name = if let Some(tool_name) = tool_name { + format!("{}::{}", tool_name, lint_name) + } else { + lint_name.to_string() + }; + // If the lint was scoped with `tool::` check if the tool lint exists + if let Some(tool_name) = tool_name { + match self.by_name.get(&complete_name) { + None => match self.lint_groups.get(&*complete_name) { + // If the lint isn't registered, there are two possibilities: + None => { + // 1. The tool is currently running, so this lint really doesn't exist. + // FIXME: should this handle tools that never register a lint, like rustfmt? + tracing::debug!("lints={:?}", self.by_name.keys().collect::<Vec<_>>()); + let tool_prefix = format!("{}::", tool_name); + return if self.by_name.keys().any(|lint| lint.starts_with(&tool_prefix)) { + self.no_lint_suggestion(&complete_name) + } else { + // 2. The tool isn't currently running, so no lints will be registered. + // To avoid giving a false positive, ignore all unknown lints. + CheckLintNameResult::Tool(Err((None, String::new()))) + }; + } + Some(LintGroup { lint_ids, .. }) => { + return CheckLintNameResult::Tool(Ok(&lint_ids)); + } + }, + Some(&Id(ref id)) => return CheckLintNameResult::Tool(Ok(slice::from_ref(id))), + // If the lint was registered as removed or renamed by the lint tool, we don't need + // to treat tool_lints and rustc lints different and can use the code below. + _ => {} + } + } + match self.by_name.get(&complete_name) { + Some(&Renamed(ref new_name, _)) => CheckLintNameResult::Warning( + format!("lint `{}` has been renamed to `{}`", complete_name, new_name), + Some(new_name.to_owned()), + ), + Some(&Removed(ref reason)) => CheckLintNameResult::Warning( + format!("lint `{}` has been removed: {}", complete_name, reason), + None, + ), + None => match self.lint_groups.get(&*complete_name) { + // If neither the lint, nor the lint group exists check if there is a `clippy::` + // variant of this lint + None => self.check_tool_name_for_backwards_compat(&complete_name, "clippy"), + Some(LintGroup { lint_ids, depr, .. }) => { + // Check if the lint group name is deprecated + if let Some(LintAlias { name, silent }) = depr { + let LintGroup { lint_ids, .. } = self.lint_groups.get(name).unwrap(); + return if *silent { + CheckLintNameResult::Ok(&lint_ids) + } else { + CheckLintNameResult::Tool(Err((Some(&lint_ids), (*name).to_string()))) + }; + } + CheckLintNameResult::Ok(&lint_ids) + } + }, + Some(&Id(ref id)) => CheckLintNameResult::Ok(slice::from_ref(id)), + Some(&Ignored) => CheckLintNameResult::Ok(&[]), + } + } + + fn no_lint_suggestion(&self, lint_name: &str) -> CheckLintNameResult<'_> { + let name_lower = lint_name.to_lowercase(); + + if lint_name.chars().any(char::is_uppercase) && self.find_lints(&name_lower).is_ok() { + // First check if the lint name is (partly) in upper case instead of lower case... + return CheckLintNameResult::NoLint(Some(Symbol::intern(&name_lower))); + } + // ...if not, search for lints with a similar name + let groups = self.lint_groups.keys().copied().map(Symbol::intern); + let lints = self.lints.iter().map(|l| Symbol::intern(&l.name_lower())); + let names: Vec<Symbol> = groups.chain(lints).collect(); + let suggestion = find_best_match_for_name(&names, Symbol::intern(&name_lower), None); + CheckLintNameResult::NoLint(suggestion) + } + + fn check_tool_name_for_backwards_compat( + &self, + lint_name: &str, + tool_name: &str, + ) -> CheckLintNameResult<'_> { + let complete_name = format!("{}::{}", tool_name, lint_name); + match self.by_name.get(&complete_name) { + None => match self.lint_groups.get(&*complete_name) { + // Now we are sure, that this lint exists nowhere + None => self.no_lint_suggestion(lint_name), + Some(LintGroup { lint_ids, depr, .. }) => { + // Reaching this would be weird, but let's cover this case anyway + if let Some(LintAlias { name, silent }) = depr { + let LintGroup { lint_ids, .. } = self.lint_groups.get(name).unwrap(); + return if *silent { + CheckLintNameResult::Tool(Err((Some(&lint_ids), complete_name))) + } else { + CheckLintNameResult::Tool(Err((Some(&lint_ids), (*name).to_string()))) + }; + } + CheckLintNameResult::Tool(Err((Some(&lint_ids), complete_name))) + } + }, + Some(&Id(ref id)) => { + CheckLintNameResult::Tool(Err((Some(slice::from_ref(id)), complete_name))) + } + Some(other) => { + tracing::debug!("got renamed lint {:?}", other); + CheckLintNameResult::NoLint(None) + } + } + } +} + +/// Context for lint checking outside of type inference. +pub struct LateContext<'tcx> { + /// Type context we're checking in. + pub tcx: TyCtxt<'tcx>, + + /// Current body, or `None` if outside a body. + pub enclosing_body: Option<hir::BodyId>, + + /// Type-checking results for the current body. Access using the `typeck_results` + /// and `maybe_typeck_results` methods, which handle querying the typeck results on demand. + // FIXME(eddyb) move all the code accessing internal fields like this, + // to this module, to avoid exposing it to lint logic. + pub(super) cached_typeck_results: Cell<Option<&'tcx ty::TypeckResults<'tcx>>>, + + /// Parameter environment for the item we are in. + pub param_env: ty::ParamEnv<'tcx>, + + /// Items accessible from the crate being checked. + pub access_levels: &'tcx AccessLevels, + + /// The store of registered lints and the lint levels. + pub lint_store: &'tcx LintStore, + + pub last_node_with_lint_attrs: hir::HirId, + + /// Generic type parameters in scope for the item we are in. + pub generics: Option<&'tcx hir::Generics<'tcx>>, + + /// We are only looking at one module + pub only_module: bool, +} + +/// Context for lint checking of the AST, after expansion, before lowering to HIR. +pub struct EarlyContext<'a> { + pub builder: LintLevelsBuilder<'a>, + pub buffered: LintBuffer, +} + +pub trait LintPassObject: Sized {} + +impl LintPassObject for EarlyLintPassObject {} + +impl LintPassObject for LateLintPassObject {} + +pub trait LintContext: Sized { + type PassObject: LintPassObject; + + fn sess(&self) -> &Session; + fn lints(&self) -> &LintStore; + + fn lookup_with_diagnostics( + &self, + lint: &'static Lint, + span: Option<impl Into<MultiSpan>>, + decorate: impl for<'a> FnOnce(LintDiagnosticBuilder<'a, ()>), + diagnostic: BuiltinLintDiagnostics, + ) { + self.lookup(lint, span, |lint| { + // We first generate a blank diagnostic. + let mut db = lint.build(""); + + // 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 {}invisible unicode text flow control codepoint{}", + an, + 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(), + &mut db, + n, + path_span, + incl_angl_brckt, + insertion_span, + ); + } + BuiltinLintDiagnostics::UnknownCrateTypes(span, note, sugg) => { + db.span_suggestion(span, ¬e, 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 `{}` is already {} here", ident, introduced), + ); + } + } + BuiltinLintDiagnostics::DeprecatedMacro(suggestion, span) => { + stability::deprecation_suggestion(&mut 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(¬e); + } + 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::UnexpectedCfg((name, name_span), None) => { + let Some(names_valid) = &sess.parse_sess.check_config.names_valid else { + bug!("it shouldn't be possible to have a diagnostic on a name if name checking is not enabled"); + }; + let possibilities: Vec<Symbol> = names_valid.iter().map(|s| *s).collect(); + + // Suggest the most probable if we found one + if let Some(best_match) = find_best_match_for_name(&possibilities, name, None) { + db.span_suggestion(name_span, "did you mean", best_match, Applicability::MaybeIncorrect); + } + }, + BuiltinLintDiagnostics::UnexpectedCfg((name, name_span), Some((value, value_span))) => { + let Some(values) = &sess.parse_sess.check_config.values_valid.get(&name) else { + bug!("it shouldn't be possible to have a diagnostic on a value whose name is not in values"); + }; + let possibilities: Vec<Symbol> = values.iter().map(|&s| s).collect(); + + // 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(", "); + db.note(&format!("expected values for `{name}` are: {possibilities}")); + } + + // 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, "did you mean", format!("\"{best_match}\""), Applicability::MaybeIncorrect); + } + } else { + db.note(&format!("no expected value for `{name}`")); + if name != sym::feature { + db.span_suggestion(name_span.shrink_to_hi().to(value_span), "remove the value", "", Applicability::MaybeIncorrect); + } + } + }, + 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"); + 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()) + }; + db.multipart_suggestion( + msg, + vec![(deletion_span, String::new()), (use_span, replace_lt)], + Applicability::MachineApplicable, + ); + }, + BuiltinLintDiagnostics::SingleUseLifetime { + param_span: _, + use_span: None, + deletion_span, + } => { + debug!(?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 `{}` by position", named_arg_name); + 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 }; + + db.span_suggestion_verbose( + positional_arg_to_replace, + "use the named argument by name to avoid ambiguity", + name, + Applicability::MaybeIncorrect, + ); + } + } + } + // Rewrap `db`, and pass control to the user. + decorate(LintDiagnosticBuilder::new(db)); + }); + } + + // FIXME: These methods should not take an Into<MultiSpan> -- instead, callers should need to + // set the span in their `decorate` function (preferably using set_span). + fn lookup<S: Into<MultiSpan>>( + &self, + lint: &'static Lint, + span: Option<S>, + decorate: impl for<'a> FnOnce(LintDiagnosticBuilder<'a, ()>), + ); + + /// Emit a lint at `span` from a lint struct (some type that implements `DecorateLint`, + /// typically generated by `#[derive(LintDiagnostic)]`). + fn emit_spanned_lint<S: Into<MultiSpan>>( + &self, + lint: &'static Lint, + span: S, + decorator: impl for<'a> DecorateLint<'a, ()>, + ) { + self.lookup(lint, Some(span), |diag| decorator.decorate_lint(diag)); + } + + fn struct_span_lint<S: Into<MultiSpan>>( + &self, + lint: &'static Lint, + span: S, + decorate: impl for<'a> FnOnce(LintDiagnosticBuilder<'a, ()>), + ) { + self.lookup(lint, Some(span), decorate); + } + + /// Emit a lint from a lint struct (some type that implements `DecorateLint`, typically + /// generated by `#[derive(LintDiagnostic)]`). + fn emit_lint(&self, lint: &'static Lint, decorator: impl for<'a> DecorateLint<'a, ()>) { + self.lookup(lint, None as Option<Span>, |diag| decorator.decorate_lint(diag)); + } + + /// Emit a lint at the appropriate level, with no associated span. + fn lint( + &self, + lint: &'static Lint, + decorate: impl for<'a> FnOnce(LintDiagnosticBuilder<'a, ()>), + ) { + self.lookup(lint, None as Option<Span>, decorate); + } + + /// This returns the lint level for the given lint at the current location. + fn get_lint_level(&self, lint: &'static Lint) -> Level; + + /// This function can be used to manually fulfill an expectation. This can + /// be used for lints which contain several spans, and should be suppressed, + /// if either location was marked with an expectation. + /// + /// Note that this function should only be called for [`LintExpectationId`]s + /// retrieved from the current lint pass. Buffered or manually created ids can + /// cause ICEs. + fn fulfill_expectation(&self, expectation: LintExpectationId) { + // We need to make sure that submitted expectation ids are correctly fulfilled suppressed + // and stored between compilation sessions. To not manually do these steps, we simply create + // a dummy diagnostic and emit is as usual, which will be suppressed and stored like a normal + // expected lint diagnostic. + self.sess() + .struct_expect( + "this is a dummy diagnostic, to submit and store an expectation", + expectation, + ) + .emit(); + } +} + +impl<'a> EarlyContext<'a> { + pub(crate) fn new( + sess: &'a Session, + warn_about_weird_lints: bool, + lint_store: &'a LintStore, + registered_tools: &'a RegisteredTools, + buffered: LintBuffer, + ) -> EarlyContext<'a> { + EarlyContext { + builder: LintLevelsBuilder::new( + sess, + warn_about_weird_lints, + lint_store, + registered_tools, + ), + buffered, + } + } +} + +impl LintContext for LateContext<'_> { + type PassObject = LateLintPassObject; + + /// Gets the overall compiler `Session` object. + fn sess(&self) -> &Session { + &self.tcx.sess + } + + fn lints(&self) -> &LintStore { + &*self.lint_store + } + + fn lookup<S: Into<MultiSpan>>( + &self, + lint: &'static Lint, + span: Option<S>, + decorate: impl for<'a> FnOnce(LintDiagnosticBuilder<'a, ()>), + ) { + let hir_id = self.last_node_with_lint_attrs; + + match span { + Some(s) => self.tcx.struct_span_lint_hir(lint, hir_id, s, decorate), + None => self.tcx.struct_lint_node(lint, hir_id, decorate), + } + } + + fn get_lint_level(&self, lint: &'static Lint) -> Level { + self.tcx.lint_level_at_node(lint, self.last_node_with_lint_attrs).0 + } +} + +impl LintContext for EarlyContext<'_> { + type PassObject = EarlyLintPassObject; + + /// Gets the overall compiler `Session` object. + fn sess(&self) -> &Session { + &self.builder.sess() + } + + fn lints(&self) -> &LintStore { + self.builder.lint_store() + } + + fn lookup<S: Into<MultiSpan>>( + &self, + lint: &'static Lint, + span: Option<S>, + decorate: impl for<'a> FnOnce(LintDiagnosticBuilder<'a, ()>), + ) { + self.builder.struct_lint(lint, span.map(|s| s.into()), decorate) + } + + fn get_lint_level(&self, lint: &'static Lint) -> Level { + self.builder.lint_level(lint).0 + } +} + +impl<'tcx> LateContext<'tcx> { + /// Gets the type-checking results for the current body, + /// or `None` if outside a body. + pub fn maybe_typeck_results(&self) -> Option<&'tcx ty::TypeckResults<'tcx>> { + self.cached_typeck_results.get().or_else(|| { + self.enclosing_body.map(|body| { + let typeck_results = self.tcx.typeck_body(body); + self.cached_typeck_results.set(Some(typeck_results)); + typeck_results + }) + }) + } + + /// Gets the type-checking results for the current body. + /// As this will ICE if called outside bodies, only call when working with + /// `Expr` or `Pat` nodes (they are guaranteed to be found only in bodies). + #[track_caller] + pub fn typeck_results(&self) -> &'tcx ty::TypeckResults<'tcx> { + self.maybe_typeck_results().expect("`LateContext::typeck_results` called outside of body") + } + + /// Returns the final resolution of a `QPath`, or `Res::Err` if unavailable. + /// Unlike `.typeck_results().qpath_res(qpath, id)`, this can be used even outside + /// bodies (e.g. for paths in `hir::Ty`), without any risk of ICE-ing. + pub fn qpath_res(&self, qpath: &hir::QPath<'_>, id: hir::HirId) -> Res { + match *qpath { + hir::QPath::Resolved(_, ref path) => path.res, + hir::QPath::TypeRelative(..) | hir::QPath::LangItem(..) => self + .maybe_typeck_results() + .filter(|typeck_results| typeck_results.hir_owner == id.owner) + .or_else(|| { + if self.tcx.has_typeck_results(id.owner.to_def_id()) { + Some(self.tcx.typeck(id.owner)) + } else { + None + } + }) + .and_then(|typeck_results| typeck_results.type_dependent_def(id)) + .map_or(Res::Err, |(kind, def_id)| Res::Def(kind, def_id)), + } + } + + /// Check if a `DefId`'s path matches the given absolute type path usage. + /// + /// Anonymous scopes such as `extern` imports are matched with `kw::Empty`; + /// inherent `impl` blocks are matched with the name of the type. + /// + /// Instead of using this method, it is often preferable to instead use + /// `rustc_diagnostic_item` or a `lang_item`. This is less prone to errors + /// as paths get invalidated if the target definition moves. + /// + /// # Examples + /// + /// ```rust,ignore (no context or def id available) + /// if cx.match_def_path(def_id, &[sym::core, sym::option, sym::Option]) { + /// // The given `def_id` is that of an `Option` type + /// } + /// ``` + /// + /// Used by clippy, but should be replaced by diagnostic items eventually. + pub fn match_def_path(&self, def_id: DefId, path: &[Symbol]) -> bool { + let names = self.get_def_path(def_id); + + names.len() == path.len() && iter::zip(names, path).all(|(a, &b)| a == b) + } + + /// Gets the absolute path of `def_id` as a vector of `Symbol`. + /// + /// # Examples + /// + /// ```rust,ignore (no context or def id available) + /// let def_path = cx.get_def_path(def_id); + /// if let &[sym::core, sym::option, sym::Option] = &def_path[..] { + /// // The given `def_id` is that of an `Option` type + /// } + /// ``` + pub fn get_def_path(&self, def_id: DefId) -> Vec<Symbol> { + pub struct AbsolutePathPrinter<'tcx> { + pub tcx: TyCtxt<'tcx>, + } + + impl<'tcx> Printer<'tcx> for AbsolutePathPrinter<'tcx> { + type Error = !; + + type Path = Vec<Symbol>; + type Region = (); + type Type = (); + type DynExistential = (); + type Const = (); + + fn tcx(&self) -> TyCtxt<'tcx> { + self.tcx + } + + fn print_region(self, _region: ty::Region<'_>) -> Result<Self::Region, Self::Error> { + Ok(()) + } + + fn print_type(self, _ty: Ty<'tcx>) -> Result<Self::Type, Self::Error> { + Ok(()) + } + + fn print_dyn_existential( + self, + _predicates: &'tcx ty::List<ty::Binder<'tcx, ty::ExistentialPredicate<'tcx>>>, + ) -> Result<Self::DynExistential, Self::Error> { + Ok(()) + } + + fn print_const(self, _ct: ty::Const<'tcx>) -> Result<Self::Const, Self::Error> { + Ok(()) + } + + fn path_crate(self, cnum: CrateNum) -> Result<Self::Path, Self::Error> { + Ok(vec![self.tcx.crate_name(cnum)]) + } + + fn path_qualified( + self, + self_ty: Ty<'tcx>, + trait_ref: Option<ty::TraitRef<'tcx>>, + ) -> Result<Self::Path, Self::Error> { + if trait_ref.is_none() { + if let ty::Adt(def, substs) = self_ty.kind() { + return self.print_def_path(def.did(), substs); + } + } + + // This shouldn't ever be needed, but just in case: + with_no_trimmed_paths!({ + Ok(vec![match trait_ref { + Some(trait_ref) => Symbol::intern(&format!("{:?}", trait_ref)), + None => Symbol::intern(&format!("<{}>", self_ty)), + }]) + }) + } + + fn path_append_impl( + self, + print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>, + _disambiguated_data: &DisambiguatedDefPathData, + self_ty: Ty<'tcx>, + trait_ref: Option<ty::TraitRef<'tcx>>, + ) -> Result<Self::Path, Self::Error> { + let mut path = print_prefix(self)?; + + // This shouldn't ever be needed, but just in case: + path.push(match trait_ref { + Some(trait_ref) => { + with_no_trimmed_paths!(Symbol::intern(&format!( + "<impl {} for {}>", + trait_ref.print_only_trait_path(), + self_ty + ))) + } + None => { + with_no_trimmed_paths!(Symbol::intern(&format!("<impl {}>", self_ty))) + } + }); + + Ok(path) + } + + fn path_append( + self, + print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>, + disambiguated_data: &DisambiguatedDefPathData, + ) -> Result<Self::Path, Self::Error> { + let mut path = print_prefix(self)?; + + // Skip `::{{extern}}` blocks and `::{{constructor}}` on tuple/unit structs. + if let DefPathData::ForeignMod | DefPathData::Ctor = disambiguated_data.data { + return Ok(path); + } + + path.push(Symbol::intern(&disambiguated_data.data.to_string())); + Ok(path) + } + + fn path_generic_args( + self, + print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>, + _args: &[GenericArg<'tcx>], + ) -> Result<Self::Path, Self::Error> { + print_prefix(self) + } + } + + AbsolutePathPrinter { tcx: self.tcx }.print_def_path(def_id, &[]).unwrap() + } +} + +impl<'tcx> abi::HasDataLayout for LateContext<'tcx> { + #[inline] + fn data_layout(&self) -> &abi::TargetDataLayout { + &self.tcx.data_layout + } +} + +impl<'tcx> ty::layout::HasTyCtxt<'tcx> for LateContext<'tcx> { + #[inline] + fn tcx(&self) -> TyCtxt<'tcx> { + self.tcx + } +} + +impl<'tcx> ty::layout::HasParamEnv<'tcx> for LateContext<'tcx> { + #[inline] + fn param_env(&self) -> ty::ParamEnv<'tcx> { + self.param_env + } +} + +impl<'tcx> LayoutOfHelpers<'tcx> for LateContext<'tcx> { + type LayoutOfResult = Result<TyAndLayout<'tcx>, LayoutError<'tcx>>; + + #[inline] + fn handle_layout_err(&self, err: LayoutError<'tcx>, _: Span, _: Ty<'tcx>) -> LayoutError<'tcx> { + err + } +} + +pub fn parse_lint_and_tool_name(lint_name: &str) -> (Option<Symbol>, &str) { + match lint_name.split_once("::") { + Some((tool_name, lint_name)) => { + let tool_name = Symbol::intern(tool_name); + + (Some(tool_name), lint_name) + } + None => (None, lint_name), + } +} |