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use std::cmp::Reverse;
use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
use log::debug;
use rustc::hir::def::{self, DefKind, CtorKind, Namespace::*};
use rustc::hir::def_id::{CRATE_DEF_INDEX, DefId};
use rustc::session::{Session, config::nightly_options};
use syntax::ast::{self, Expr, ExprKind, Ident};
use syntax::ext::base::MacroKind;
use syntax::symbol::{Symbol, kw};
use syntax_pos::{BytePos, Span};
type Res = def::Res<ast::NodeId>;
use crate::macros::ParentScope;
use crate::resolve_imports::{ImportDirective, ImportDirectiveSubclass, ImportResolver};
use crate::{import_candidate_to_enum_paths, is_self_type, is_self_value, path_names_to_string};
use crate::{AssocSuggestion, CrateLint, ImportSuggestion, ModuleOrUniformRoot, PathResult,
PathSource, Resolver, Segment, Suggestion};
impl<'a> Resolver<'a> {
/// Handles error reporting for `smart_resolve_path_fragment` function.
/// Creates base error and amends it with one short label and possibly some longer helps/notes.
pub(crate) fn smart_resolve_report_errors(
&mut self,
path: &[Segment],
span: Span,
source: PathSource<'_>,
res: Option<Res>,
) -> (DiagnosticBuilder<'a>, Vec<ImportSuggestion>) {
let ident_span = path.last().map_or(span, |ident| ident.ident.span);
let ns = source.namespace();
let is_expected = &|res| source.is_expected(res);
let is_enum_variant = &|res| {
if let Res::Def(DefKind::Variant, _) = res { true } else { false }
};
// Make the base error.
let expected = source.descr_expected();
let path_str = Segment::names_to_string(path);
let item_str = path.last().unwrap().ident;
let code = source.error_code(res.is_some());
let (base_msg, fallback_label, base_span) = if let Some(res) = res {
(format!("expected {}, found {} `{}`", expected, res.descr(), path_str),
format!("not a {}", expected),
span)
} else {
let item_span = path.last().unwrap().ident.span;
let (mod_prefix, mod_str) = if path.len() == 1 {
(String::new(), "this scope".to_string())
} else if path.len() == 2 && path[0].ident.name == kw::PathRoot {
(String::new(), "the crate root".to_string())
} else {
let mod_path = &path[..path.len() - 1];
let mod_prefix = match self.resolve_path_without_parent_scope(
mod_path, Some(TypeNS), false, span, CrateLint::No
) {
PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
module.def_kind(),
_ => None,
}.map_or(String::new(), |kind| format!("{} ", kind.descr()));
(mod_prefix, format!("`{}`", Segment::names_to_string(mod_path)))
};
(format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
format!("not found in {}", mod_str),
item_span)
};
let code = DiagnosticId::Error(code.into());
let mut err = self.session.struct_span_err_with_code(base_span, &base_msg, code);
// Emit help message for fake-self from other languages (e.g., `this` in Javascript).
if ["this", "my"].contains(&&*item_str.as_str())
&& self.self_value_is_available(path[0].ident.span, span) {
err.span_suggestion(
span,
"did you mean",
"self".to_string(),
Applicability::MaybeIncorrect,
);
}
// Emit special messages for unresolved `Self` and `self`.
if is_self_type(path, ns) {
__diagnostic_used!(E0411);
err.code(DiagnosticId::Error("E0411".into()));
err.span_label(span, format!("`Self` is only available in impls, traits, \
and type definitions"));
return (err, Vec::new());
}
if is_self_value(path, ns) {
debug!("smart_resolve_path_fragment: E0424, source={:?}", source);
__diagnostic_used!(E0424);
err.code(DiagnosticId::Error("E0424".into()));
err.span_label(span, match source {
PathSource::Pat => {
format!("`self` value is a keyword \
and may not be bound to \
variables or shadowed")
}
_ => {
format!("`self` value is a keyword \
only available in methods \
with `self` parameter")
}
});
return (err, Vec::new());
}
// Try to lookup name in more relaxed fashion for better error reporting.
let ident = path.last().unwrap().ident;
let candidates = self.lookup_import_candidates(ident, ns, is_expected)
.drain(..)
.filter(|ImportSuggestion { did, .. }| {
match (did, res.and_then(|res| res.opt_def_id())) {
(Some(suggestion_did), Some(actual_did)) => *suggestion_did != actual_did,
_ => true,
}
})
.collect::<Vec<_>>();
let crate_def_id = DefId::local(CRATE_DEF_INDEX);
if candidates.is_empty() && is_expected(Res::Def(DefKind::Enum, crate_def_id)) {
let enum_candidates =
self.lookup_import_candidates(ident, ns, is_enum_variant);
let mut enum_candidates = enum_candidates.iter()
.map(|suggestion| {
import_candidate_to_enum_paths(&suggestion)
}).collect::<Vec<_>>();
enum_candidates.sort();
if !enum_candidates.is_empty() {
// Contextualize for E0412 "cannot find type", but don't belabor the point
// (that it's a variant) for E0573 "expected type, found variant".
let preamble = if res.is_none() {
let others = match enum_candidates.len() {
1 => String::new(),
2 => " and 1 other".to_owned(),
n => format!(" and {} others", n)
};
format!("there is an enum variant `{}`{}; ",
enum_candidates[0].0, others)
} else {
String::new()
};
let msg = format!("{}try using the variant's enum", preamble);
err.span_suggestions(
span,
&msg,
enum_candidates.into_iter()
.map(|(_variant_path, enum_ty_path)| enum_ty_path)
// Variants re-exported in prelude doesn't mean `prelude::v1` is the
// type name!
// FIXME: is there a more principled way to do this that
// would work for other re-exports?
.filter(|enum_ty_path| enum_ty_path != "std::prelude::v1")
// Also write `Option` rather than `std::prelude::v1::Option`.
.map(|enum_ty_path| {
// FIXME #56861: DRY-er prelude filtering.
enum_ty_path.trim_start_matches("std::prelude::v1::").to_owned()
}),
Applicability::MachineApplicable,
);
}
}
if path.len() == 1 && self.self_type_is_available(span) {
if let Some(candidate) = self.lookup_assoc_candidate(ident, ns, is_expected) {
let self_is_available = self.self_value_is_available(path[0].ident.span, span);
match candidate {
AssocSuggestion::Field => {
if self_is_available {
err.span_suggestion(
span,
"you might have meant to use the available field",
format!("self.{}", path_str),
Applicability::MachineApplicable,
);
} else {
err.span_label(
span,
"a field by this name exists in `Self`",
);
}
}
AssocSuggestion::MethodWithSelf if self_is_available => {
err.span_suggestion(
span,
"try",
format!("self.{}", path_str),
Applicability::MachineApplicable,
);
}
AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
err.span_suggestion(
span,
"try",
format!("Self::{}", path_str),
Applicability::MachineApplicable,
);
}
}
return (err, candidates);
}
}
let mut levenshtein_worked = false;
// Try Levenshtein algorithm.
let suggestion = self.lookup_typo_candidate(path, ns, is_expected, span);
if let Some(suggestion) = suggestion {
let msg = format!(
"{} {} with a similar name exists",
suggestion.article, suggestion.kind
);
err.span_suggestion(
ident_span,
&msg,
suggestion.candidate.to_string(),
Applicability::MaybeIncorrect,
);
levenshtein_worked = true;
}
// Try context-dependent help if relaxed lookup didn't work.
if let Some(res) = res {
if self.smart_resolve_context_dependent_help(&mut err,
span,
source,
res,
&path_str,
&fallback_label) {
return (err, candidates);
}
}
// Fallback label.
if !levenshtein_worked {
err.span_label(base_span, fallback_label);
self.type_ascription_suggestion(&mut err, base_span);
}
(err, candidates)
}
fn followed_by_brace(&self, span: Span) -> (bool, Option<(Span, String)>) {
// HACK(estebank): find a better way to figure out that this was a
// parser issue where a struct literal is being used on an expression
// where a brace being opened means a block is being started. Look
// ahead for the next text to see if `span` is followed by a `{`.
let sm = self.session.source_map();
let mut sp = span;
loop {
sp = sm.next_point(sp);
match sm.span_to_snippet(sp) {
Ok(ref snippet) => {
if snippet.chars().any(|c| { !c.is_whitespace() }) {
break;
}
}
_ => break,
}
}
let followed_by_brace = match sm.span_to_snippet(sp) {
Ok(ref snippet) if snippet == "{" => true,
_ => false,
};
// In case this could be a struct literal that needs to be surrounded
// by parenthesis, find the appropriate span.
let mut i = 0;
let mut closing_brace = None;
loop {
sp = sm.next_point(sp);
match sm.span_to_snippet(sp) {
Ok(ref snippet) => {
if snippet == "}" {
let sp = span.to(sp);
if let Ok(snippet) = sm.span_to_snippet(sp) {
closing_brace = Some((sp, snippet));
}
break;
}
}
_ => break,
}
i += 1;
// The bigger the span, the more likely we're incorrect --
// bound it to 100 chars long.
if i > 100 {
break;
}
}
return (followed_by_brace, closing_brace)
}
/// Provides context-dependent help for errors reported by the `smart_resolve_path_fragment`
/// function.
/// Returns `true` if able to provide context-dependent help.
fn smart_resolve_context_dependent_help(
&mut self,
err: &mut DiagnosticBuilder<'a>,
span: Span,
source: PathSource<'_>,
res: Res,
path_str: &str,
fallback_label: &str,
) -> bool {
let ns = source.namespace();
let is_expected = &|res| source.is_expected(res);
let path_sep = |err: &mut DiagnosticBuilder<'_>, expr: &Expr| match expr.node {
ExprKind::Field(_, ident) => {
err.span_suggestion(
expr.span,
"use the path separator to refer to an item",
format!("{}::{}", path_str, ident),
Applicability::MaybeIncorrect,
);
true
}
ExprKind::MethodCall(ref segment, ..) => {
let span = expr.span.with_hi(segment.ident.span.hi());
err.span_suggestion(
span,
"use the path separator to refer to an item",
format!("{}::{}", path_str, segment.ident),
Applicability::MaybeIncorrect,
);
true
}
_ => false,
};
let mut bad_struct_syntax_suggestion = || {
let (followed_by_brace, closing_brace) = self.followed_by_brace(span);
let mut suggested = false;
match source {
PathSource::Expr(Some(parent)) => {
suggested = path_sep(err, &parent);
}
PathSource::Expr(None) if followed_by_brace == true => {
if let Some((sp, snippet)) = closing_brace {
err.span_suggestion(
sp,
"surround the struct literal with parenthesis",
format!("({})", snippet),
Applicability::MaybeIncorrect,
);
} else {
err.span_label(
span, // Note the parenthesis surrounding the suggestion below
format!("did you mean `({} {{ /* fields */ }})`?", path_str),
);
}
suggested = true;
},
_ => {}
}
if !suggested {
err.span_label(
span,
format!("did you mean `{} {{ /* fields */ }}`?", path_str),
);
}
};
match (res, source) {
(Res::Def(DefKind::Macro(..), _), _) => {
err.span_suggestion(
span,
"use `!` to invoke the macro",
format!("{}!", path_str),
Applicability::MaybeIncorrect,
);
if path_str == "try" && span.rust_2015() {
err.note("if you want the `try` keyword, you need to be in the 2018 edition");
}
}
(Res::Def(DefKind::TyAlias, _), PathSource::Trait(_)) => {
err.span_label(span, "type aliases cannot be used as traits");
if nightly_options::is_nightly_build() {
err.note("did you mean to use a trait alias?");
}
}
(Res::Def(DefKind::Mod, _), PathSource::Expr(Some(parent))) => {
if !path_sep(err, &parent) {
return false;
}
}
(Res::Def(DefKind::Enum, def_id), PathSource::TupleStruct)
| (Res::Def(DefKind::Enum, def_id), PathSource::Expr(..)) => {
if let Some(variants) = self.collect_enum_variants(def_id) {
if !variants.is_empty() {
let msg = if variants.len() == 1 {
"try using the enum's variant"
} else {
"try using one of the enum's variants"
};
err.span_suggestions(
span,
msg,
variants.iter().map(path_names_to_string),
Applicability::MaybeIncorrect,
);
}
} else {
err.note("did you mean to use one of the enum's variants?");
}
},
(Res::Def(DefKind::Struct, def_id), _) if ns == ValueNS => {
if let Some((ctor_def, ctor_vis))
= self.struct_constructors.get(&def_id).cloned() {
let accessible_ctor = self.is_accessible(ctor_vis);
if is_expected(ctor_def) && !accessible_ctor {
err.span_label(
span,
format!("constructor is not visible here due to private fields"),
);
}
} else {
bad_struct_syntax_suggestion();
}
}
(Res::Def(DefKind::Union, _), _) |
(Res::Def(DefKind::Variant, _), _) |
(Res::Def(DefKind::Ctor(_, CtorKind::Fictive), _), _) if ns == ValueNS => {
bad_struct_syntax_suggestion();
}
(Res::SelfTy(..), _) if ns == ValueNS => {
err.span_label(span, fallback_label);
err.note("can't use `Self` as a constructor, you must use the implemented struct");
}
(Res::Def(DefKind::TyAlias, _), _)
| (Res::Def(DefKind::AssocTy, _), _) if ns == ValueNS => {
err.note("can't use a type alias as a constructor");
}
_ => return false,
}
true
}
}
impl<'a, 'b> ImportResolver<'a, 'b> {
/// Adds suggestions for a path that cannot be resolved.
pub(crate) fn make_path_suggestion(
&mut self,
span: Span,
mut path: Vec<Segment>,
parent_scope: &ParentScope<'b>,
) -> Option<(Vec<Segment>, Vec<String>)> {
debug!("make_path_suggestion: span={:?} path={:?}", span, path);
match (path.get(0), path.get(1)) {
// `{{root}}::ident::...` on both editions.
// On 2015 `{{root}}` is usually added implicitly.
(Some(fst), Some(snd)) if fst.ident.name == kw::PathRoot &&
!snd.ident.is_path_segment_keyword() => {}
// `ident::...` on 2018.
(Some(fst), _) if fst.ident.span.rust_2018() &&
!fst.ident.is_path_segment_keyword() => {
// Insert a placeholder that's later replaced by `self`/`super`/etc.
path.insert(0, Segment::from_ident(Ident::invalid()));
}
_ => return None,
}
self.make_missing_self_suggestion(span, path.clone(), parent_scope)
.or_else(|| self.make_missing_crate_suggestion(span, path.clone(), parent_scope))
.or_else(|| self.make_missing_super_suggestion(span, path.clone(), parent_scope))
.or_else(|| self.make_external_crate_suggestion(span, path, parent_scope))
}
/// Suggest a missing `self::` if that resolves to an correct module.
///
/// ```
/// |
/// LL | use foo::Bar;
/// | ^^^ did you mean `self::foo`?
/// ```
fn make_missing_self_suggestion(
&mut self,
span: Span,
mut path: Vec<Segment>,
parent_scope: &ParentScope<'b>,
) -> Option<(Vec<Segment>, Vec<String>)> {
// Replace first ident with `self` and check if that is valid.
path[0].ident.name = kw::SelfLower;
let result = self.resolve_path(&path, None, parent_scope, false, span, CrateLint::No);
debug!("make_missing_self_suggestion: path={:?} result={:?}", path, result);
if let PathResult::Module(..) = result {
Some((path, Vec::new()))
} else {
None
}
}
/// Suggests a missing `crate::` if that resolves to an correct module.
///
/// ```
/// |
/// LL | use foo::Bar;
/// | ^^^ did you mean `crate::foo`?
/// ```
fn make_missing_crate_suggestion(
&mut self,
span: Span,
mut path: Vec<Segment>,
parent_scope: &ParentScope<'b>,
) -> Option<(Vec<Segment>, Vec<String>)> {
// Replace first ident with `crate` and check if that is valid.
path[0].ident.name = kw::Crate;
let result = self.resolve_path(&path, None, parent_scope, false, span, CrateLint::No);
debug!("make_missing_crate_suggestion: path={:?} result={:?}", path, result);
if let PathResult::Module(..) = result {
Some((
path,
vec![
"`use` statements changed in Rust 2018; read more at \
<https://doc.rust-lang.org/edition-guide/rust-2018/module-system/path-\
clarity.html>".to_string()
],
))
} else {
None
}
}
/// Suggests a missing `super::` if that resolves to an correct module.
///
/// ```
/// |
/// LL | use foo::Bar;
/// | ^^^ did you mean `super::foo`?
/// ```
fn make_missing_super_suggestion(
&mut self,
span: Span,
mut path: Vec<Segment>,
parent_scope: &ParentScope<'b>,
) -> Option<(Vec<Segment>, Vec<String>)> {
// Replace first ident with `crate` and check if that is valid.
path[0].ident.name = kw::Super;
let result = self.resolve_path(&path, None, parent_scope, false, span, CrateLint::No);
debug!("make_missing_super_suggestion: path={:?} result={:?}", path, result);
if let PathResult::Module(..) = result {
Some((path, Vec::new()))
} else {
None
}
}
/// Suggests a missing external crate name if that resolves to an correct module.
///
/// ```
/// |
/// LL | use foobar::Baz;
/// | ^^^^^^ did you mean `baz::foobar`?
/// ```
///
/// Used when importing a submodule of an external crate but missing that crate's
/// name as the first part of path.
fn make_external_crate_suggestion(
&mut self,
span: Span,
mut path: Vec<Segment>,
parent_scope: &ParentScope<'b>,
) -> Option<(Vec<Segment>, Vec<String>)> {
if path[1].ident.span.rust_2015() {
return None;
}
// Sort extern crate names in reverse order to get
// 1) some consistent ordering for emitted dignostics, and
// 2) `std` suggestions before `core` suggestions.
let mut extern_crate_names =
self.resolver.extern_prelude.iter().map(|(ident, _)| ident.name).collect::<Vec<_>>();
extern_crate_names.sort_by_key(|name| Reverse(name.as_str()));
for name in extern_crate_names.into_iter() {
// Replace first ident with a crate name and check if that is valid.
path[0].ident.name = name;
let result = self.resolve_path(&path, None, parent_scope, false, span, CrateLint::No);
debug!("make_external_crate_suggestion: name={:?} path={:?} result={:?}",
name, path, result);
if let PathResult::Module(..) = result {
return Some((path, Vec::new()));
}
}
None
}
/// Suggests importing a macro from the root of the crate rather than a module within
/// the crate.
///
/// ```
/// help: a macro with this name exists at the root of the crate
/// |
/// LL | use issue_59764::makro;
/// | ^^^^^^^^^^^^^^^^^^
/// |
/// = note: this could be because a macro annotated with `#[macro_export]` will be exported
/// at the root of the crate instead of the module where it is defined
/// ```
pub(crate) fn check_for_module_export_macro(
&self,
directive: &'b ImportDirective<'b>,
module: ModuleOrUniformRoot<'b>,
ident: Ident,
) -> Option<(Option<Suggestion>, Vec<String>)> {
let mut crate_module = if let ModuleOrUniformRoot::Module(module) = module {
module
} else {
return None;
};
while let Some(parent) = crate_module.parent {
crate_module = parent;
}
if ModuleOrUniformRoot::same_def(ModuleOrUniformRoot::Module(crate_module), module) {
// Don't make a suggestion if the import was already from the root of the
// crate.
return None;
}
let resolutions = crate_module.resolutions.borrow();
let resolution = resolutions.get(&(ident, MacroNS))?;
let binding = resolution.borrow().binding()?;
if let Res::Def(DefKind::Macro(MacroKind::Bang), _) = binding.res() {
let module_name = crate_module.kind.name().unwrap();
let import = match directive.subclass {
ImportDirectiveSubclass::SingleImport { source, target, .. } if source != target =>
format!("{} as {}", source, target),
_ => format!("{}", ident),
};
let mut corrections: Vec<(Span, String)> = Vec::new();
if !directive.is_nested() {
// Assume this is the easy case of `use issue_59764::foo::makro;` and just remove
// intermediate segments.
corrections.push((directive.span, format!("{}::{}", module_name, import)));
} else {
// Find the binding span (and any trailing commas and spaces).
// ie. `use a::b::{c, d, e};`
// ^^^
let (found_closing_brace, binding_span) = find_span_of_binding_until_next_binding(
self.resolver.session, directive.span, directive.use_span,
);
debug!("check_for_module_export_macro: found_closing_brace={:?} binding_span={:?}",
found_closing_brace, binding_span);
let mut removal_span = binding_span;
if found_closing_brace {
// If the binding span ended with a closing brace, as in the below example:
// ie. `use a::b::{c, d};`
// ^
// Then expand the span of characters to remove to include the previous
// binding's trailing comma.
// ie. `use a::b::{c, d};`
// ^^^
if let Some(previous_span) = extend_span_to_previous_binding(
self.resolver.session, binding_span,
) {
debug!("check_for_module_export_macro: previous_span={:?}", previous_span);
removal_span = removal_span.with_lo(previous_span.lo());
}
}
debug!("check_for_module_export_macro: removal_span={:?}", removal_span);
// Remove the `removal_span`.
corrections.push((removal_span, "".to_string()));
// Find the span after the crate name and if it has nested imports immediatately
// after the crate name already.
// ie. `use a::b::{c, d};`
// ^^^^^^^^^
// or `use a::{b, c, d}};`
// ^^^^^^^^^^^
let (has_nested, after_crate_name) = find_span_immediately_after_crate_name(
self.resolver.session, module_name, directive.use_span,
);
debug!("check_for_module_export_macro: has_nested={:?} after_crate_name={:?}",
has_nested, after_crate_name);
let source_map = self.resolver.session.source_map();
// Add the import to the start, with a `{` if required.
let start_point = source_map.start_point(after_crate_name);
if let Ok(start_snippet) = source_map.span_to_snippet(start_point) {
corrections.push((
start_point,
if has_nested {
// In this case, `start_snippet` must equal '{'.
format!("{}{}, ", start_snippet, import)
} else {
// In this case, add a `{`, then the moved import, then whatever
// was there before.
format!("{{{}, {}", import, start_snippet)
}
));
}
// Add a `};` to the end if nested, matching the `{` added at the start.
if !has_nested {
corrections.push((source_map.end_point(after_crate_name),
"};".to_string()));
}
}
let suggestion = Some((
corrections,
String::from("a macro with this name exists at the root of the crate"),
Applicability::MaybeIncorrect,
));
let note = vec![
"this could be because a macro annotated with `#[macro_export]` will be exported \
at the root of the crate instead of the module where it is defined".to_string(),
];
Some((suggestion, note))
} else {
None
}
}
}
/// Given a `binding_span` of a binding within a use statement:
///
/// ```
/// use foo::{a, b, c};
/// ^
/// ```
///
/// then return the span until the next binding or the end of the statement:
///
/// ```
/// use foo::{a, b, c};
/// ^^^
/// ```
pub(crate) fn find_span_of_binding_until_next_binding(
sess: &Session,
binding_span: Span,
use_span: Span,
) -> (bool, Span) {
let source_map = sess.source_map();
// Find the span of everything after the binding.
// ie. `a, e};` or `a};`
let binding_until_end = binding_span.with_hi(use_span.hi());
// Find everything after the binding but not including the binding.
// ie. `, e};` or `};`
let after_binding_until_end = binding_until_end.with_lo(binding_span.hi());
// Keep characters in the span until we encounter something that isn't a comma or
// whitespace.
// ie. `, ` or ``.
//
// Also note whether a closing brace character was encountered. If there
// was, then later go backwards to remove any trailing commas that are left.
let mut found_closing_brace = false;
let after_binding_until_next_binding = source_map.span_take_while(
after_binding_until_end,
|&ch| {
if ch == '}' { found_closing_brace = true; }
ch == ' ' || ch == ','
}
);
// Combine the two spans.
// ie. `a, ` or `a`.
//
// Removing these would leave `issue_52891::{d, e};` or `issue_52891::{d, e, };`
let span = binding_span.with_hi(after_binding_until_next_binding.hi());
(found_closing_brace, span)
}
/// Given a `binding_span`, return the span through to the comma or opening brace of the previous
/// binding.
///
/// ```
/// use foo::a::{a, b, c};
/// ^^--- binding span
/// |
/// returned span
///
/// use foo::{a, b, c};
/// --- binding span
/// ```
pub(crate) fn extend_span_to_previous_binding(
sess: &Session,
binding_span: Span,
) -> Option<Span> {
let source_map = sess.source_map();
// `prev_source` will contain all of the source that came before the span.
// Then split based on a command and take the first (ie. closest to our span)
// snippet. In the example, this is a space.
let prev_source = source_map.span_to_prev_source(binding_span).ok()?;
let prev_comma = prev_source.rsplit(',').collect::<Vec<_>>();
let prev_starting_brace = prev_source.rsplit('{').collect::<Vec<_>>();
if prev_comma.len() <= 1 || prev_starting_brace.len() <= 1 {
return None;
}
let prev_comma = prev_comma.first().unwrap();
let prev_starting_brace = prev_starting_brace.first().unwrap();
// If the amount of source code before the comma is greater than
// the amount of source code before the starting brace then we've only
// got one item in the nested item (eg. `issue_52891::{self}`).
if prev_comma.len() > prev_starting_brace.len() {
return None;
}
Some(binding_span.with_lo(BytePos(
// Take away the number of bytes for the characters we've found and an
// extra for the comma.
binding_span.lo().0 - (prev_comma.as_bytes().len() as u32) - 1
)))
}
/// Given a `use_span` of a binding within a use statement, returns the highlighted span and if
/// it is a nested use tree.
///
/// ```
/// use foo::a::{b, c};
/// ^^^^^^^^^^ // false
///
/// use foo::{a, b, c};
/// ^^^^^^^^^^ // true
///
/// use foo::{a, b::{c, d}};
/// ^^^^^^^^^^^^^^^ // true
/// ```
fn find_span_immediately_after_crate_name(
sess: &Session,
module_name: Symbol,
use_span: Span,
) -> (bool, Span) {
debug!("find_span_immediately_after_crate_name: module_name={:?} use_span={:?}",
module_name, use_span);
let source_map = sess.source_map();
// Using `use issue_59764::foo::{baz, makro};` as an example throughout..
let mut num_colons = 0;
// Find second colon.. `use issue_59764:`
let until_second_colon = source_map.span_take_while(use_span, |c| {
if *c == ':' { num_colons += 1; }
match c {
':' if num_colons == 2 => false,
_ => true,
}
});
// Find everything after the second colon.. `foo::{baz, makro};`
let from_second_colon = use_span.with_lo(until_second_colon.hi() + BytePos(1));
let mut found_a_non_whitespace_character = false;
// Find the first non-whitespace character in `from_second_colon`.. `f`
let after_second_colon = source_map.span_take_while(from_second_colon, |c| {
if found_a_non_whitespace_character { return false; }
if !c.is_whitespace() { found_a_non_whitespace_character = true; }
true
});
// Find the first `{` in from_second_colon.. `foo::{`
let next_left_bracket = source_map.span_through_char(from_second_colon, '{');
(next_left_bracket == after_second_colon, from_second_colon)
}
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