diff options
Diffstat (limited to 'compiler/rustc_span/src/lib.rs')
| -rw-r--r-- | compiler/rustc_span/src/lib.rs | 92 |
1 files changed, 52 insertions, 40 deletions
diff --git a/compiler/rustc_span/src/lib.rs b/compiler/rustc_span/src/lib.rs index 9b0e009b2cd..e95b743b1ce 100644 --- a/compiler/rustc_span/src/lib.rs +++ b/compiler/rustc_span/src/lib.rs @@ -17,6 +17,7 @@ // tidy-alphabetical-start #![allow(internal_features)] +#![cfg_attr(bootstrap, feature(round_char_boundary))] #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")] #![doc(rust_logo)] #![feature(array_windows)] @@ -26,7 +27,6 @@ #![feature(map_try_insert)] #![feature(negative_impls)] #![feature(read_buf)] -#![feature(round_char_boundary)] #![feature(rustc_attrs)] #![feature(rustdoc_internals)] // tidy-alphabetical-end @@ -66,7 +66,8 @@ pub use span_encoding::{DUMMY_SP, Span}; pub mod symbol; pub use symbol::{ - ByteSymbol, Ident, MacroRulesNormalizedIdent, STDLIB_STABLE_CRATES, Symbol, kw, sym, + ByteSymbol, Ident, MacroRulesNormalizedIdent, Macros20NormalizedIdent, STDLIB_STABLE_CRATES, + Symbol, kw, sym, }; mod analyze_source_file; @@ -167,6 +168,7 @@ where } } +#[inline] pub fn with_session_globals<R, F>(f: F) -> R where F: FnOnce(&SessionGlobals) -> R, @@ -708,19 +710,24 @@ impl Span { if !ctxt.is_root() { ctxt.outer_expn_data().call_site.source_callsite() } else { self } } - /// The `Span` for the tokens in the previous macro expansion from which `self` was generated, - /// if any. + /// Returns the call-site span of the last macro expansion which produced this `Span`. + /// (see [`ExpnData::call_site`]). Returns `None` if this is not an expansion. pub fn parent_callsite(self) -> Option<Span> { let ctxt = self.ctxt(); (!ctxt.is_root()).then(|| ctxt.outer_expn_data().call_site) } - /// Walk down the expansion ancestors to find a span that's contained within `outer`. + /// Find the first ancestor span that's contained within `outer`. + /// + /// This method traverses the macro expansion ancestors until it finds the first span + /// that's contained within `outer`. /// - /// The span returned by this method may have a different [`SyntaxContext`] as `outer`. + /// The span returned by this method may have a different [`SyntaxContext`] than `outer`. /// If you need to extend the span, use [`find_ancestor_inside_same_ctxt`] instead, /// because joining spans with different syntax contexts can create unexpected results. /// + /// This is used to find the span of the macro call when a parent expr span, i.e. `outer`, is known. + /// /// [`find_ancestor_inside_same_ctxt`]: Self::find_ancestor_inside_same_ctxt pub fn find_ancestor_inside(mut self, outer: Span) -> Option<Span> { while !outer.contains(self) { @@ -729,8 +736,10 @@ impl Span { Some(self) } - /// Walk down the expansion ancestors to find a span with the same [`SyntaxContext`] as - /// `other`. + /// Find the first ancestor span with the same [`SyntaxContext`] as `other`. + /// + /// This method traverses the macro expansion ancestors until it finds a span + /// that has the same [`SyntaxContext`] as `other`. /// /// Like [`find_ancestor_inside_same_ctxt`], but specifically for when spans might not /// overlap. Take care when using this, and prefer [`find_ancestor_inside`] or @@ -746,9 +755,12 @@ impl Span { Some(self) } - /// Walk down the expansion ancestors to find a span that's contained within `outer` and + /// Find the first ancestor span that's contained within `outer` and /// has the same [`SyntaxContext`] as `outer`. /// + /// This method traverses the macro expansion ancestors until it finds a span + /// that is both contained within `outer` and has the same [`SyntaxContext`] as `outer`. + /// /// This method is the combination of [`find_ancestor_inside`] and /// [`find_ancestor_in_same_ctxt`] and should be preferred when extending the returned span. /// If you do not need to modify the span, use [`find_ancestor_inside`] instead. @@ -762,43 +774,43 @@ impl Span { Some(self) } - /// Recursively walk down the expansion ancestors to find the oldest ancestor span with the same - /// [`SyntaxContext`] the initial span. + /// Find the first ancestor span that does not come from an external macro. /// - /// This method is suitable for peeling through *local* macro expansions to find the "innermost" - /// span that is still local and shares the same [`SyntaxContext`]. For example, given + /// This method traverses the macro expansion ancestors until it finds a span + /// that is either from user-written code or from a local macro (defined in the current crate). /// - /// ```ignore (illustrative example, contains type error) - /// macro_rules! outer { - /// ($x: expr) => { - /// inner!($x) - /// } - /// } + /// External macros are those defined in dependencies or the standard library. + /// This method is useful for reporting errors in user-controllable code and avoiding + /// diagnostics inside external macros. /// - /// macro_rules! inner { - /// ($x: expr) => { - /// format!("error: {}", $x) - /// //~^ ERROR mismatched types - /// } - /// } + /// # See also /// - /// fn bar(x: &str) -> Result<(), Box<dyn std::error::Error>> { - /// Err(outer!(x)) - /// } - /// ``` + /// - [`Self::find_ancestor_not_from_macro`] + /// - [`Self::in_external_macro`] + pub fn find_ancestor_not_from_extern_macro(mut self, sm: &SourceMap) -> Option<Span> { + while self.in_external_macro(sm) { + self = self.parent_callsite()?; + } + Some(self) + } + + /// Find the first ancestor span that does not come from any macro expansion. /// - /// if provided the initial span of `outer!(x)` inside `bar`, this method will recurse - /// the parent callsites until we reach `format!("error: {}", $x)`, at which point it is the - /// oldest ancestor span that is both still local and shares the same [`SyntaxContext`] as the - /// initial span. - pub fn find_oldest_ancestor_in_same_ctxt(self) -> Span { - let mut cur = self; - while cur.eq_ctxt(self) - && let Some(parent_callsite) = cur.parent_callsite() - { - cur = parent_callsite; + /// This method traverses the macro expansion ancestors until it finds a span + /// that originates from user-written code rather than any macro-generated code. + /// + /// This method is useful for reporting errors at the exact location users wrote code + /// and providing suggestions at directly editable locations. + /// + /// # See also + /// + /// - [`Self::find_ancestor_not_from_extern_macro`] + /// - [`Span::from_expansion`] + pub fn find_ancestor_not_from_macro(mut self) -> Option<Span> { + while self.from_expansion() { + self = self.parent_callsite()?; } - cur + Some(self) } /// Edition of the crate from which this span came. |