X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=src%2Fimports.rs;h=0f635fe1ccb3584210a21debfaa5f423384f556a;hb=1e2258ffa949bf4d273259e78d326857c0b2bb3d;hp=56d23fa98277ec372a55abdfe8b9cdf1a61e1173;hpb=35466adbfe90939552580c15161a1ee9b9f1c4a5;p=rust.git diff --git a/src/imports.rs b/src/imports.rs index 56d23fa9827..0f635fe1ccb 100644 --- a/src/imports.rs +++ b/src/imports.rs @@ -1,536 +1,1210 @@ -// Copyright 2015 The Rust Project Developers. See the COPYRIGHT -// file at the top-level directory of this distribution and at -// http://rust-lang.org/COPYRIGHT. +use std::borrow::Cow; +use std::cmp::Ordering; +use std::fmt; + +use rustc_ast::ast::{self, UseTreeKind}; +use rustc_span::{ + symbol::{self, sym}, + BytePos, Span, DUMMY_SP, +}; + +use crate::comment::combine_strs_with_missing_comments; +use crate::config::lists::*; +use crate::config::{Edition, IndentStyle}; +use crate::lists::{ + definitive_tactic, itemize_list, write_list, ListFormatting, ListItem, Separator, +}; +use crate::rewrite::{Rewrite, RewriteContext}; +use crate::shape::Shape; +use crate::source_map::SpanUtils; +use crate::spanned::Spanned; +use crate::utils::{is_same_visibility, mk_sp, rewrite_ident}; +use crate::visitor::FmtVisitor; + +/// Returns a name imported by a `use` declaration. +/// E.g., returns `Ordering` for `std::cmp::Ordering` and `self` for `std::cmp::self`. +pub(crate) fn path_to_imported_ident(path: &ast::Path) -> symbol::Ident { + path.segments.last().unwrap().ident +} + +impl<'a> FmtVisitor<'a> { + pub(crate) fn format_import(&mut self, item: &ast::Item, tree: &ast::UseTree) { + let span = item.span(); + let shape = self.shape(); + let rw = UseTree::from_ast( + &self.get_context(), + tree, + None, + Some(item.vis.clone()), + Some(item.span.lo()), + Some(item.attrs.clone()), + ) + .rewrite_top_level(&self.get_context(), shape); + match rw { + Some(ref s) if s.is_empty() => { + // Format up to last newline + let prev_span = mk_sp(self.last_pos, source!(self, span).lo()); + let trimmed_snippet = self.snippet(prev_span).trim_end(); + let span_end = self.last_pos + BytePos(trimmed_snippet.len() as u32); + self.format_missing(span_end); + // We have an excessive newline from the removed import. + if self.buffer.ends_with('\n') { + self.buffer.pop(); + self.line_number -= 1; + } + self.last_pos = source!(self, span).hi(); + } + Some(ref s) => { + self.format_missing_with_indent(source!(self, span).lo()); + self.push_str(s); + self.last_pos = source!(self, span).hi(); + } + None => { + self.format_missing_with_indent(source!(self, span).lo()); + self.format_missing(source!(self, span).hi()); + } + } + } +} + +// Ordering of imports + +// We order imports by translating to our own representation and then sorting. +// The Rust AST data structures are really bad for this. Rustfmt applies a bunch +// of normalisations to imports and since we want to sort based on the result +// of these (and to maintain idempotence) we must apply the same normalisations +// to the data structures for sorting. // -// Licensed under the Apache License, Version 2.0 or the MIT license -// , at your -// option. This file may not be copied, modified, or distributed -// except according to those terms. +// We sort `self` and `super` before other imports, then identifier imports, +// then glob imports, then lists of imports. We do not take aliases into account +// when ordering unless the imports are identical except for the alias (rare in +// practice). -use std::cmp::Ordering; +// FIXME(#2531): we should unify the comparison code here with the formatting +// code elsewhere since we are essentially string-ifying twice. Furthermore, by +// parsing to our own format on comparison, we repeat a lot of work when +// sorting. + +// FIXME we do a lot of allocation to make our own representation. +#[derive(Clone, Eq, PartialEq)] +pub(crate) enum UseSegment { + Ident(String, Option), + Slf(Option), + Super(Option), + Crate(Option), + Glob, + List(Vec), +} + +#[derive(Clone)] +pub(crate) struct UseTree { + pub(crate) path: Vec, + pub(crate) span: Span, + // Comment information within nested use tree. + pub(crate) list_item: Option, + // Additional fields for top level use items. + // Should we have another struct for top-level use items rather than reusing this? + visibility: Option, + attrs: Option>, +} -use syntax::ast; -use syntax::codemap::{BytePos, Span}; - -use spanned::Spanned; -use codemap::SpanUtils; -use comment::combine_strs_with_missing_comments; -use config::IndentStyle; -use lists::{definitive_tactic, itemize_list, write_list, DefinitiveListTactic, ListFormatting, - ListItem, Separator, SeparatorPlace, SeparatorTactic}; -use rewrite::{Rewrite, RewriteContext}; -use shape::Shape; -use types::{rewrite_path, PathContext}; -use utils::{format_visibility, mk_sp}; -use visitor::{rewrite_extern_crate, FmtVisitor}; - -fn path_of(a: &ast::ViewPath_) -> &ast::Path { - match *a { - ast::ViewPath_::ViewPathSimple(_, ref p) - | ast::ViewPath_::ViewPathGlob(ref p) - | ast::ViewPath_::ViewPathList(ref p, _) => p, +impl PartialEq for UseTree { + fn eq(&self, other: &UseTree) -> bool { + self.path == other.path } } +impl Eq for UseTree {} -fn compare_path_segments(a: &ast::PathSegment, b: &ast::PathSegment) -> Ordering { - a.identifier.name.as_str().cmp(&b.identifier.name.as_str()) +impl Spanned for UseTree { + fn span(&self) -> Span { + let lo = if let Some(ref attrs) = self.attrs { + attrs.iter().next().map_or(self.span.lo(), |a| a.span.lo()) + } else { + self.span.lo() + }; + mk_sp(lo, self.span.hi()) + } } -fn compare_paths(a: &ast::Path, b: &ast::Path) -> Ordering { - for segment in a.segments.iter().zip(b.segments.iter()) { - let ord = compare_path_segments(segment.0, segment.1); - if ord != Ordering::Equal { - return ord; +impl UseSegment { + // Clone a version of self with any top-level alias removed. + fn remove_alias(&self) -> UseSegment { + match *self { + UseSegment::Ident(ref s, _) => UseSegment::Ident(s.clone(), None), + UseSegment::Slf(_) => UseSegment::Slf(None), + UseSegment::Super(_) => UseSegment::Super(None), + UseSegment::Crate(_) => UseSegment::Crate(None), + _ => self.clone(), } } - a.segments.len().cmp(&b.segments.len()) + + fn from_path_segment( + context: &RewriteContext<'_>, + path_seg: &ast::PathSegment, + modsep: bool, + ) -> Option { + let name = rewrite_ident(context, path_seg.ident); + if name.is_empty() || name == "{{root}}" { + return None; + } + Some(match name { + "self" => UseSegment::Slf(None), + "super" => UseSegment::Super(None), + "crate" => UseSegment::Crate(None), + _ => { + let mod_sep = if modsep { "::" } else { "" }; + UseSegment::Ident(format!("{}{}", mod_sep, name), None) + } + }) + } } -fn compare_path_list_items(a: &ast::PathListItem, b: &ast::PathListItem) -> Ordering { - let a_name_str = &*a.node.name.name.as_str(); - let b_name_str = &*b.node.name.name.as_str(); - let name_ordering = if a_name_str == "self" { - if b_name_str == "self" { - Ordering::Equal - } else { - Ordering::Less +pub(crate) fn merge_use_trees(use_trees: Vec, merge_by: SharedPrefix) -> Vec { + let mut result = Vec::with_capacity(use_trees.len()); + for use_tree in use_trees { + if use_tree.has_comment() || use_tree.attrs.is_some() { + result.push(use_tree); + continue; } - } else if b_name_str == "self" { - Ordering::Greater - } else { - a_name_str.cmp(b_name_str) - }; - if name_ordering == Ordering::Equal { - match a.node.rename { - Some(a_rename) => match b.node.rename { - Some(b_rename) => a_rename.name.as_str().cmp(&b_rename.name.as_str()), - None => Ordering::Greater, - }, - None => Ordering::Less, + + for flattened in use_tree.flatten() { + if let Some(tree) = result + .iter_mut() + .find(|tree| tree.share_prefix(&flattened, merge_by)) + { + tree.merge(&flattened, merge_by); + } else { + result.push(flattened); + } } - } else { - name_ordering } + result } -fn compare_path_list_item_lists( - a_items: &[ast::PathListItem], - b_items: &[ast::PathListItem], -) -> Ordering { - let mut a = a_items.to_owned(); - let mut b = b_items.to_owned(); - a.sort_by(|a, b| compare_path_list_items(a, b)); - b.sort_by(|a, b| compare_path_list_items(a, b)); - for comparison_pair in a.iter().zip(b.iter()) { - let ord = compare_path_list_items(comparison_pair.0, comparison_pair.1); - if ord != Ordering::Equal { - return ord; - } - } - a.len().cmp(&b.len()) +pub(crate) fn flatten_use_trees(use_trees: Vec) -> Vec { + use_trees + .into_iter() + .flat_map(UseTree::flatten) + .map(|mut tree| { + // If a path ends in `::self`, rewrite it to `::{self}`. + if let Some(UseSegment::Slf(..)) = tree.path.last() { + let self_segment = tree.path.pop().unwrap(); + tree.path.push(UseSegment::List(vec![UseTree::from_path( + vec![self_segment], + DUMMY_SP, + )])); + } + tree + }) + .collect() } -fn compare_view_path_types(a: &ast::ViewPath_, b: &ast::ViewPath_) -> Ordering { - use syntax::ast::ViewPath_::*; - match (a, b) { - (&ViewPathSimple(..), &ViewPathSimple(..)) | (&ViewPathGlob(_), &ViewPathGlob(_)) => { - Ordering::Equal - } - (&ViewPathSimple(..), _) | (&ViewPathGlob(_), &ViewPathList(..)) => Ordering::Less, - (&ViewPathList(_, ref a_items), &ViewPathList(_, ref b_items)) => { - compare_path_list_item_lists(a_items, b_items) - } - (&ViewPathGlob(_), &ViewPathSimple(..)) | (&ViewPathList(..), _) => Ordering::Greater, +impl fmt::Debug for UseTree { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + fmt::Display::fmt(self, f) } } -fn compare_view_paths(a: &ast::ViewPath_, b: &ast::ViewPath_) -> Ordering { - match compare_paths(path_of(a), path_of(b)) { - Ordering::Equal => compare_view_path_types(a, b), - cmp => cmp, +impl fmt::Debug for UseSegment { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + fmt::Display::fmt(self, f) } } -fn compare_use_items(context: &RewriteContext, a: &ast::Item, b: &ast::Item) -> Option { - match (&a.node, &b.node) { - (&ast::ItemKind::Use(ref a_vp), &ast::ItemKind::Use(ref b_vp)) => { - Some(compare_view_paths(&a_vp.node, &b_vp.node)) +impl fmt::Display for UseSegment { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + match *self { + UseSegment::Glob => write!(f, "*"), + UseSegment::Ident(ref s, _) => write!(f, "{}", s), + UseSegment::Slf(..) => write!(f, "self"), + UseSegment::Super(..) => write!(f, "super"), + UseSegment::Crate(..) => write!(f, "crate"), + UseSegment::List(ref list) => { + write!(f, "{{")?; + for (i, item) in list.iter().enumerate() { + if i != 0 { + write!(f, ", ")?; + } + write!(f, "{}", item)?; + } + write!(f, "}}") + } } - (&ast::ItemKind::ExternCrate(..), &ast::ItemKind::ExternCrate(..)) => { - Some(context.snippet(a.span).cmp(&context.snippet(b.span))) + } +} +impl fmt::Display for UseTree { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + for (i, segment) in self.path.iter().enumerate() { + if i != 0 { + write!(f, "::")?; + } + write!(f, "{}", segment)?; } - _ => None, + Ok(()) } } -// TODO (some day) remove unused imports, expand globs, compress many single -// imports into a list import. - -fn rewrite_view_path_prefix( - path: &ast::Path, - context: &RewriteContext, - shape: Shape, -) -> Option { - let path_str = if path.segments.last().unwrap().identifier.to_string() == "self" - && path.segments.len() > 1 - { - let path = &ast::Path { - span: path.span, - segments: path.segments[..path.segments.len() - 1].to_owned(), - }; - rewrite_path(context, PathContext::Import, None, path, shape)? - } else { - rewrite_path(context, PathContext::Import, None, path, shape)? - }; - Some(path_str) -} +impl UseTree { + // Rewrite use tree with `use ` and a trailing `;`. + pub(crate) fn rewrite_top_level( + &self, + context: &RewriteContext<'_>, + shape: Shape, + ) -> Option { + let vis = self.visibility.as_ref().map_or(Cow::from(""), |vis| { + crate::utils::format_visibility(context, &vis) + }); + let use_str = self + .rewrite(context, shape.offset_left(vis.len())?) + .map(|s| { + if s.is_empty() { + s + } else { + format!("{}use {};", vis, s) + } + })?; + match self.attrs { + Some(ref attrs) if !attrs.is_empty() => { + let attr_str = attrs.rewrite(context, shape)?; + let lo = attrs.last().as_ref()?.span.hi(); + let hi = self.span.lo(); + let span = mk_sp(lo, hi); -impl Rewrite for ast::ViewPath { - fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option { - match self.node { - ast::ViewPath_::ViewPathList(ref path, ref path_list) => { - rewrite_use_list(shape, path, path_list, self.span, context) - } - ast::ViewPath_::ViewPathGlob(ref path) => { - // 4 = "::*".len() - let prefix_shape = shape.sub_width(3)?; - let path_str = rewrite_view_path_prefix(path, context, prefix_shape)?; - Some(format!("{}::*", path_str)) - } - ast::ViewPath_::ViewPathSimple(ident, ref path) => { - let ident_str = ident.to_string(); - // 4 = " as ".len() - let prefix_shape = shape.sub_width(ident_str.len() + 4)?; - let path_str = rewrite_view_path_prefix(path, context, prefix_shape)?; - - Some(if path.segments.last().unwrap().identifier == ident { - path_str + let allow_extend = if attrs.len() == 1 { + let line_len = attr_str.len() + 1 + use_str.len(); + !attrs.first().unwrap().is_doc_comment() + && context.config.inline_attribute_width() >= line_len } else { - format!("{} as {}", path_str, ident_str) - }) + false + }; + + combine_strs_with_missing_comments( + context, + &attr_str, + &use_str, + span, + shape, + allow_extend, + ) } + _ => Some(use_str), } } -} -// Rewrite `use foo;` WITHOUT attributes. -fn rewrite_import( - context: &RewriteContext, - vis: &ast::Visibility, - vp: &ast::ViewPath, - attrs: &[ast::Attribute], - shape: Shape, -) -> Option { - let vis = format_visibility(vis); - // 4 = `use `, 1 = `;` - let rw = shape - .offset_left(vis.len() + 4) - .and_then(|shape| shape.sub_width(1)) - .and_then(|shape| match vp.node { - // If we have an empty path list with no attributes, we erase it - ast::ViewPath_::ViewPathList(_, ref path_list) - if path_list.is_empty() && attrs.is_empty() => - { - Some("".into()) - } - _ => vp.rewrite(context, shape), - }); - match rw { - Some(ref s) if !s.is_empty() => Some(format!("{}use {};", vis, s)), - _ => rw, + // FIXME: Use correct span? + // The given span is essentially incorrect, since we are reconstructing + // use-statements. This should not be a problem, though, since we have + // already tried to extract comment and observed that there are no comment + // around the given use item, and the span will not be used afterward. + fn from_path(path: Vec, span: Span) -> UseTree { + UseTree { + path, + span, + list_item: None, + visibility: None, + attrs: None, + } } -} -fn rewrite_imports( - context: &RewriteContext, - use_items: &[&ast::Item], - shape: Shape, - span: Span, -) -> Option { - let items = itemize_list( - context.codemap, - use_items.iter(), - "", - ";", - |item| item.span().lo(), - |item| item.span().hi(), - |item| { - let attrs_str = item.attrs.rewrite(context, shape)?; - - let missed_span = if item.attrs.is_empty() { - mk_sp(item.span.lo(), item.span.lo()) - } else { - mk_sp(item.attrs.last().unwrap().span.hi(), item.span.lo()) - }; + pub(crate) fn from_ast_with_normalization( + context: &RewriteContext<'_>, + item: &ast::Item, + ) -> Option { + match item.kind { + ast::ItemKind::Use(ref use_tree) => Some( + UseTree::from_ast( + context, + use_tree, + None, + Some(item.vis.clone()), + Some(item.span.lo()), + if item.attrs.is_empty() { + None + } else { + Some(item.attrs.clone()) + }, + ) + .normalize(), + ), + _ => None, + } + } - let item_str = match item.node { - ast::ItemKind::Use(ref vp) => { - rewrite_import(context, &item.vis, vp, &item.attrs, shape)? - } - ast::ItemKind::ExternCrate(..) => rewrite_extern_crate(context, item)?, - _ => return None, - }; + fn from_ast( + context: &RewriteContext<'_>, + a: &ast::UseTree, + list_item: Option, + visibility: Option, + opt_lo: Option, + attrs: Option>, + ) -> UseTree { + let span = if let Some(lo) = opt_lo { + mk_sp(lo, a.span.hi()) + } else { + a.span + }; + let mut result = UseTree { + path: vec![], + span, + list_item, + visibility, + attrs, + }; - combine_strs_with_missing_comments( - context, - &attrs_str, - &item_str, - missed_span, - shape, - false, - ) - }, - span.lo(), - span.hi(), - false, - ); - let mut item_pair_vec: Vec<_> = items.zip(use_items.iter()).collect(); - item_pair_vec.sort_by(|a, b| compare_use_items(context, a.1, b.1).unwrap()); - let item_vec: Vec<_> = item_pair_vec.into_iter().map(|pair| pair.0).collect(); - - let fmt = ListFormatting { - tactic: DefinitiveListTactic::Vertical, - separator: "", - trailing_separator: SeparatorTactic::Never, - separator_place: SeparatorPlace::Back, - shape: shape, - ends_with_newline: true, - preserve_newline: false, - config: context.config, - }; + let leading_modsep = + context.config.edition() >= Edition::Edition2018 && a.prefix.is_global(); - write_list(&item_vec, &fmt) -} + let mut modsep = leading_modsep; -impl<'a> FmtVisitor<'a> { - pub fn format_imports(&mut self, use_items: &[&ast::Item]) { - if use_items.is_empty() { - return; + for p in &a.prefix.segments { + if let Some(use_segment) = UseSegment::from_path_segment(context, p, modsep) { + result.path.push(use_segment); + modsep = false; + } } - let lo = use_items.first().unwrap().span().lo(); - let hi = use_items.last().unwrap().span().hi(); - let span = mk_sp(lo, hi); - let rw = rewrite_imports(&self.get_context(), use_items, self.shape(), span); - self.push_rewrite(span, rw); + match a.kind { + UseTreeKind::Glob => { + // in case of a global path and the glob starts at the root, e.g., "::*" + if a.prefix.segments.len() == 1 && leading_modsep { + result.path.push(UseSegment::Ident("".to_owned(), None)); + } + result.path.push(UseSegment::Glob); + } + UseTreeKind::Nested(ref list) => { + // Extract comments between nested use items. + // This needs to be done before sorting use items. + let items: Vec<_> = itemize_list( + context.snippet_provider, + list.iter().map(|(tree, _)| tree), + "}", + ",", + |tree| tree.span.lo(), + |tree| tree.span.hi(), + |_| Some("".to_owned()), // We only need comments for now. + context.snippet_provider.span_after(a.span, "{"), + a.span.hi(), + false, + ) + .collect(); + // in case of a global path and the nested list starts at the root, + // e.g., "::{foo, bar}" + if a.prefix.segments.len() == 1 && leading_modsep { + result.path.push(UseSegment::Ident("".to_owned(), None)); + } + result.path.push(UseSegment::List( + list.iter() + .zip(items.into_iter()) + .map(|(t, list_item)| { + Self::from_ast(context, &t.0, Some(list_item), None, None, None) + }) + .collect(), + )); + } + UseTreeKind::Simple(ref rename, ..) => { + // If the path has leading double colons and is composed of only 2 segments, then we + // bypass the call to path_to_imported_ident which would get only the ident and + // lose the path root, e.g., `that` in `::that`. + // The span of `a.prefix` contains the leading colons. + let name = if a.prefix.segments.len() == 2 && leading_modsep { + context.snippet(a.prefix.span).to_owned() + } else { + rewrite_ident(context, path_to_imported_ident(&a.prefix)).to_owned() + }; + let alias = rename.and_then(|ident| { + if ident.name == sym::underscore_imports { + // for impl-only-use + Some("_".to_owned()) + } else if ident == path_to_imported_ident(&a.prefix) { + None + } else { + Some(rewrite_ident(context, ident).to_owned()) + } + }); + let segment = match name.as_ref() { + "self" => UseSegment::Slf(alias), + "super" => UseSegment::Super(alias), + "crate" => UseSegment::Crate(alias), + _ => UseSegment::Ident(name, alias), + }; + + // `name` is already in result. + result.path.pop(); + result.path.push(segment); + } + } + result } - pub fn format_import(&mut self, item: &ast::Item, vp: &ast::ViewPath) { - let span = item.span; - let shape = self.shape(); - let rw = rewrite_import(&self.get_context(), &item.vis, vp, &item.attrs, shape); - match rw { - Some(ref s) if s.is_empty() => { - // Format up to last newline - let prev_span = mk_sp(self.last_pos, source!(self, span).lo()); - let span_end = match self.snippet(prev_span).rfind('\n') { - Some(offset) => self.last_pos + BytePos(offset as u32), - None => source!(self, span).lo(), - }; - self.format_missing(span_end); - self.last_pos = source!(self, span).hi(); + // Do the adjustments that rustfmt does elsewhere to use paths. + pub(crate) fn normalize(mut self) -> UseTree { + let mut last = self.path.pop().expect("Empty use tree?"); + // Hack around borrow checker. + let mut normalize_sole_list = false; + let mut aliased_self = false; + + // Remove foo::{} or self without attributes. + match last { + _ if self.attrs.is_some() => (), + UseSegment::List(ref list) if list.is_empty() => { + self.path = vec![]; + return self; } - Some(ref s) => { - self.format_missing_with_indent(source!(self, span).lo()); - self.buffer.push_str(s); - self.last_pos = source!(self, span).hi(); + UseSegment::Slf(None) if self.path.is_empty() && self.visibility.is_some() => { + self.path = vec![]; + return self; } - None => { - self.format_missing_with_indent(source!(self, span).lo()); - self.format_missing(source!(self, span).hi()); + _ => (), + } + + // Normalise foo::self -> foo. + if let UseSegment::Slf(None) = last { + if !self.path.is_empty() { + return self; } } - } -} -fn rewrite_single_use_list(path_str: String, vpi: &ast::PathListItem) -> String { - let mut item_str = vpi.node.name.to_string(); - if item_str == "self" { - item_str = "".to_owned(); - } - let path_item_str = if path_str.is_empty() { - if item_str.is_empty() { - "self".to_owned() - } else { - item_str + // Normalise foo::self as bar -> foo as bar. + if let UseSegment::Slf(_) = last { + match self.path.last() { + Some(UseSegment::Ident(_, None)) => { + aliased_self = true; + } + _ => {} + } } - } else if item_str.is_empty() { - path_str - } else { - format!("{}::{}", path_str, item_str) - }; - append_alias(path_item_str, vpi) -} -fn rewrite_path_item(vpi: &&ast::PathListItem) -> Option { - Some(append_alias(vpi.node.name.to_string(), vpi)) -} + let mut done = false; + if aliased_self { + match self.path.last_mut() { + Some(UseSegment::Ident(_, ref mut old_rename)) => { + assert!(old_rename.is_none()); + if let UseSegment::Slf(Some(rename)) = last.clone() { + *old_rename = Some(rename); + done = true; + } + } + _ => unreachable!(), + } + } + + if done { + return self; + } + + // Normalise foo::{bar} -> foo::bar + if let UseSegment::List(ref list) = last { + if list.len() == 1 && list[0].to_string() != "self" { + normalize_sole_list = true; + } + } -fn append_alias(path_item_str: String, vpi: &ast::PathListItem) -> String { - match vpi.node.rename { - Some(rename) => format!("{} as {}", path_item_str, rename), - None => path_item_str, + if normalize_sole_list { + match last { + UseSegment::List(list) => { + for seg in &list[0].path { + self.path.push(seg.clone()); + } + return self.normalize(); + } + _ => unreachable!(), + } + } + + // Recursively normalize elements of a list use (including sorting the list). + if let UseSegment::List(list) = last { + let mut list = list.into_iter().map(UseTree::normalize).collect::>(); + list.sort(); + last = UseSegment::List(list); + } + + self.path.push(last); + self } -} -#[derive(Eq, PartialEq)] -enum ImportItem<'a> { - // `self` or `self as a` - SelfImport(&'a str), - // name_one, name_two, ... - SnakeCase(&'a str), - // NameOne, NameTwo, ... - CamelCase(&'a str), - // NAME_ONE, NAME_TWO, ... - AllCaps(&'a str), - // Failed to format the import item - Invalid, -} + fn has_comment(&self) -> bool { + self.list_item.as_ref().map_or(false, ListItem::has_comment) + } -impl<'a> ImportItem<'a> { - fn from_str(s: &str) -> ImportItem { - if s == "self" || s.starts_with("self as") { - ImportItem::SelfImport(s) - } else if s.chars().all(|c| c.is_lowercase() || c == '_' || c == ' ') { - ImportItem::SnakeCase(s) - } else if s.chars().all(|c| c.is_uppercase() || c == '_' || c == ' ') { - ImportItem::AllCaps(s) + fn same_visibility(&self, other: &UseTree) -> bool { + match (&self.visibility, &other.visibility) { + ( + Some(ast::Visibility { + kind: ast::VisibilityKind::Inherited, + .. + }), + None, + ) + | ( + None, + Some(ast::Visibility { + kind: ast::VisibilityKind::Inherited, + .. + }), + ) + | (None, None) => true, + (Some(ref a), Some(ref b)) => is_same_visibility(a, b), + _ => false, + } + } + + fn share_prefix(&self, other: &UseTree, shared_prefix: SharedPrefix) -> bool { + if self.path.is_empty() + || other.path.is_empty() + || self.attrs.is_some() + || !self.same_visibility(other) + { + false } else { - ImportItem::CamelCase(s) + match shared_prefix { + SharedPrefix::Crate => self.path[0] == other.path[0], + SharedPrefix::Module => { + self.path[..self.path.len() - 1] == other.path[..other.path.len() - 1] + } + } } } - fn from_opt_str(s: Option<&String>) -> ImportItem { - s.map_or(ImportItem::Invalid, |s| ImportItem::from_str(s)) + fn flatten(self) -> Vec { + if self.path.is_empty() { + return vec![self]; + } + match self.path.clone().last().unwrap() { + UseSegment::List(list) => { + if list.len() == 1 && list[0].path.len() == 1 { + match list[0].path[0] { + UseSegment::Slf(..) => return vec![self], + _ => (), + }; + } + let prefix = &self.path[..self.path.len() - 1]; + let mut result = vec![]; + for nested_use_tree in list { + for flattend in &mut nested_use_tree.clone().flatten() { + let mut new_path = prefix.to_vec(); + new_path.append(&mut flattend.path); + result.push(UseTree { + path: new_path, + span: self.span, + list_item: None, + visibility: self.visibility.clone(), + attrs: None, + }); + } + } + + result + } + _ => vec![self], + } } - fn to_str(&self) -> Option<&str> { - match *self { - ImportItem::SelfImport(s) - | ImportItem::SnakeCase(s) - | ImportItem::CamelCase(s) - | ImportItem::AllCaps(s) => Some(s), - ImportItem::Invalid => None, + fn merge(&mut self, other: &UseTree, merge_by: SharedPrefix) { + let mut prefix = 0; + for (a, b) in self.path.iter().zip(other.path.iter()) { + if *a == *b { + prefix += 1; + } else { + break; + } + } + if let Some(new_path) = merge_rest(&self.path, &other.path, prefix, merge_by) { + self.path = new_path; + self.span = self.span.to(other.span); } } +} - fn to_u32(&self) -> u32 { - match *self { - ImportItem::SelfImport(..) => 0, - ImportItem::SnakeCase(..) => 1, - ImportItem::CamelCase(..) => 2, - ImportItem::AllCaps(..) => 3, - ImportItem::Invalid => 4, +fn merge_rest( + a: &[UseSegment], + b: &[UseSegment], + mut len: usize, + merge_by: SharedPrefix, +) -> Option> { + if a.len() == len && b.len() == len { + return None; + } + if a.len() != len && b.len() != len { + if let UseSegment::List(ref list) = a[len] { + let mut list = list.clone(); + merge_use_trees_inner( + &mut list, + UseTree::from_path(b[len..].to_vec(), DUMMY_SP), + merge_by, + ); + let mut new_path = b[..len].to_vec(); + new_path.push(UseSegment::List(list)); + return Some(new_path); + } + } else if len == 1 { + let rest = if a.len() == len { &b[1..] } else { &a[1..] }; + return Some(vec![ + b[0].clone(), + UseSegment::List(vec![ + UseTree::from_path(vec![UseSegment::Slf(None)], DUMMY_SP), + UseTree::from_path(rest.to_vec(), DUMMY_SP), + ]), + ]); + } else { + len -= 1; + } + let mut list = vec![ + UseTree::from_path(a[len..].to_vec(), DUMMY_SP), + UseTree::from_path(b[len..].to_vec(), DUMMY_SP), + ]; + list.sort(); + let mut new_path = b[..len].to_vec(); + new_path.push(UseSegment::List(list)); + Some(new_path) +} + +fn merge_use_trees_inner(trees: &mut Vec, use_tree: UseTree, merge_by: SharedPrefix) { + let similar_trees = trees + .iter_mut() + .filter(|tree| tree.share_prefix(&use_tree, merge_by)); + if use_tree.path.len() == 1 && merge_by == SharedPrefix::Crate { + if let Some(tree) = similar_trees.min_by_key(|tree| tree.path.len()) { + if tree.path.len() == 1 { + return; + } + } + } else if let Some(tree) = similar_trees.max_by_key(|tree| tree.path.len()) { + if tree.path.len() > 1 { + tree.merge(&use_tree, merge_by); + return; } } + trees.push(use_tree); + trees.sort(); } -impl<'a> PartialOrd for ImportItem<'a> { - fn partial_cmp(&self, other: &ImportItem<'a>) -> Option { +impl PartialOrd for UseSegment { + fn partial_cmp(&self, other: &UseSegment) -> Option { Some(self.cmp(other)) } } +impl PartialOrd for UseTree { + fn partial_cmp(&self, other: &UseTree) -> Option { + Some(self.cmp(other)) + } +} +impl Ord for UseSegment { + fn cmp(&self, other: &UseSegment) -> Ordering { + use self::UseSegment::*; -impl<'a> Ord for ImportItem<'a> { - fn cmp(&self, other: &ImportItem<'a>) -> Ordering { - let res = self.to_u32().cmp(&other.to_u32()); - if res != Ordering::Equal { - return res; + fn is_upper_snake_case(s: &str) -> bool { + s.chars() + .all(|c| c.is_uppercase() || c == '_' || c.is_numeric()) + } + + match (self, other) { + (&Slf(ref a), &Slf(ref b)) + | (&Super(ref a), &Super(ref b)) + | (&Crate(ref a), &Crate(ref b)) => a.cmp(b), + (&Glob, &Glob) => Ordering::Equal, + (&Ident(ref ia, ref aa), &Ident(ref ib, ref ab)) => { + // snake_case < CamelCase < UPPER_SNAKE_CASE + if ia.starts_with(char::is_uppercase) && ib.starts_with(char::is_lowercase) { + return Ordering::Greater; + } + if ia.starts_with(char::is_lowercase) && ib.starts_with(char::is_uppercase) { + return Ordering::Less; + } + if is_upper_snake_case(ia) && !is_upper_snake_case(ib) { + return Ordering::Greater; + } + if !is_upper_snake_case(ia) && is_upper_snake_case(ib) { + return Ordering::Less; + } + let ident_ord = ia.cmp(ib); + if ident_ord != Ordering::Equal { + return ident_ord; + } + if aa.is_none() && ab.is_some() { + return Ordering::Less; + } + if aa.is_some() && ab.is_none() { + return Ordering::Greater; + } + aa.cmp(ab) + } + (&List(ref a), &List(ref b)) => { + for (a, b) in a.iter().zip(b.iter()) { + let ord = a.cmp(b); + if ord != Ordering::Equal { + return ord; + } + } + + a.len().cmp(&b.len()) + } + (&Slf(_), _) => Ordering::Less, + (_, &Slf(_)) => Ordering::Greater, + (&Super(_), _) => Ordering::Less, + (_, &Super(_)) => Ordering::Greater, + (&Crate(_), _) => Ordering::Less, + (_, &Crate(_)) => Ordering::Greater, + (&Ident(..), _) => Ordering::Less, + (_, &Ident(..)) => Ordering::Greater, + (&Glob, _) => Ordering::Less, + (_, &Glob) => Ordering::Greater, } - self.to_str().map_or(Ordering::Greater, |self_str| { - other - .to_str() - .map_or(Ordering::Less, |other_str| self_str.cmp(other_str)) - }) } } +impl Ord for UseTree { + fn cmp(&self, other: &UseTree) -> Ordering { + for (a, b) in self.path.iter().zip(other.path.iter()) { + let ord = a.cmp(b); + // The comparison without aliases is a hack to avoid situations like + // comparing `a::b` to `a as c` - where the latter should be ordered + // first since it is shorter. + if ord != Ordering::Equal && a.remove_alias().cmp(&b.remove_alias()) != Ordering::Equal + { + return ord; + } + } -// Pretty prints a multi-item import. -// If the path list is empty, it leaves the braces empty. -fn rewrite_use_list( + self.path.len().cmp(&other.path.len()) + } +} + +fn rewrite_nested_use_tree( + context: &RewriteContext<'_>, + use_tree_list: &[UseTree], shape: Shape, - path: &ast::Path, - path_list: &[ast::PathListItem], - span: Span, - context: &RewriteContext, ) -> Option { - // Returns a different option to distinguish `::foo` and `foo` - let path_str = rewrite_path(context, PathContext::Import, None, path, shape)?; - - match path_list.len() { - 0 => { - return rewrite_path(context, PathContext::Import, None, path, shape) - .map(|path_str| format!("{}::{{}}", path_str)); + let mut list_items = Vec::with_capacity(use_tree_list.len()); + let nested_shape = match context.config.imports_indent() { + IndentStyle::Block => shape + .block_indent(context.config.tab_spaces()) + .with_max_width(context.config) + .sub_width(1)?, + IndentStyle::Visual => shape.visual_indent(0), + }; + for use_tree in use_tree_list { + if let Some(mut list_item) = use_tree.list_item.clone() { + list_item.item = use_tree.rewrite(context, nested_shape); + list_items.push(list_item); + } else { + list_items.push(ListItem::from_str(use_tree.rewrite(context, nested_shape)?)); } - 1 => return Some(rewrite_single_use_list(path_str, &path_list[0])), - _ => (), } + let has_nested_list = use_tree_list.iter().any(|use_segment| { + use_segment + .path + .last() + .map_or(false, |last_segment| match last_segment { + UseSegment::List(..) => true, + _ => false, + }) + }); - let path_str = if path_str.is_empty() { - path_str + let remaining_width = if has_nested_list { + 0 } else { - format!("{}::", path_str) - }; - - // 2 = "{}" - let remaining_width = shape.width.checked_sub(path_str.len() + 2).unwrap_or(0); - - let mut items = { - // Dummy value, see explanation below. - let mut items = vec![ListItem::from_str("")]; - let iter = itemize_list( - context.codemap, - path_list.iter(), - "}", - ",", - |vpi| vpi.span.lo(), - |vpi| vpi.span.hi(), - rewrite_path_item, - context.codemap.span_after(span, "{"), - span.hi(), - false, - ); - items.extend(iter); - items + shape.width.saturating_sub(2) }; - // We prefixed the item list with a dummy value so that we can - // potentially move "self" to the front of the vector without touching - // the rest of the items. - let has_self = move_self_to_front(&mut items); - let first_index = if has_self { 0 } else { 1 }; - - if context.config.reorder_imported_names() { - items[1..].sort_by(|a, b| { - let a = ImportItem::from_opt_str(a.item.as_ref()); - let b = ImportItem::from_opt_str(b.item.as_ref()); - a.cmp(&b) - }); - } - let tactic = definitive_tactic( - &items[first_index..], + &list_items, context.config.imports_layout(), Separator::Comma, remaining_width, ); - let nested_indent = match context.config.imports_indent() { - IndentStyle::Block => shape.indent.block_indent(context.config), - // 1 = `{` - IndentStyle::Visual => shape.visual_indent(path_str.len() + 1).indent, - }; - - let nested_shape = match context.config.imports_indent() { - IndentStyle::Block => Shape::indented(nested_indent, context.config), - IndentStyle::Visual => Shape::legacy(remaining_width, nested_indent), - }; - let ends_with_newline = context.config.imports_indent() == IndentStyle::Block && tactic != DefinitiveListTactic::Horizontal; - - let fmt = ListFormatting { - tactic: tactic, - separator: ",", - trailing_separator: if ends_with_newline { - context.config.trailing_comma() - } else { - SeparatorTactic::Never - }, - separator_place: SeparatorPlace::Back, - shape: nested_shape, - ends_with_newline: ends_with_newline, - preserve_newline: true, - config: context.config, + let trailing_separator = if ends_with_newline { + context.config.trailing_comma() + } else { + SeparatorTactic::Never }; - let list_str = write_list(&items[first_index..], &fmt)?; + let fmt = ListFormatting::new(nested_shape, context.config) + .tactic(tactic) + .trailing_separator(trailing_separator) + .ends_with_newline(ends_with_newline) + .preserve_newline(true) + .nested(has_nested_list); + + let list_str = write_list(&list_items, &fmt)?; - let result = if list_str.contains('\n') && context.config.imports_indent() == IndentStyle::Block + let result = if (list_str.contains('\n') || list_str.len() > remaining_width) + && context.config.imports_indent() == IndentStyle::Block { format!( - "{}{{\n{}{}\n{}}}", - path_str, + "{{\n{}{}\n{}}}", nested_shape.indent.to_string(context.config), list_str, shape.indent.to_string(context.config) ) } else { - format!("{}{{{}}}", path_str, list_str) + format!("{{{}}}", list_str) }; + Some(result) } -// Returns true when self item was found. -fn move_self_to_front(items: &mut Vec) -> bool { - match items - .iter() - .position(|item| item.item.as_ref().map(|x| &x[..]) == Some("self")) - { - Some(pos) => { - items[0] = items.remove(pos); - true +impl Rewrite for UseSegment { + fn rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option { + Some(match self { + UseSegment::Ident(ref ident, Some(ref rename)) => format!("{} as {}", ident, rename), + UseSegment::Ident(ref ident, None) => ident.clone(), + UseSegment::Slf(Some(ref rename)) => format!("self as {}", rename), + UseSegment::Slf(None) => "self".to_owned(), + UseSegment::Super(Some(ref rename)) => format!("super as {}", rename), + UseSegment::Super(None) => "super".to_owned(), + UseSegment::Crate(Some(ref rename)) => format!("crate as {}", rename), + UseSegment::Crate(None) => "crate".to_owned(), + UseSegment::Glob => "*".to_owned(), + UseSegment::List(ref use_tree_list) => rewrite_nested_use_tree( + context, + use_tree_list, + // 1 = "{" and "}" + shape.offset_left(1)?.sub_width(1)?, + )?, + }) + } +} + +impl Rewrite for UseTree { + // This does NOT format attributes and visibility or add a trailing `;`. + fn rewrite(&self, context: &RewriteContext<'_>, mut shape: Shape) -> Option { + let mut result = String::with_capacity(256); + let mut iter = self.path.iter().peekable(); + while let Some(ref segment) = iter.next() { + let segment_str = segment.rewrite(context, shape)?; + result.push_str(&segment_str); + if iter.peek().is_some() { + result.push_str("::"); + // 2 = "::" + shape = shape.offset_left(2 + segment_str.len())?; + } + } + Some(result) + } +} + +#[derive(Copy, Clone, Debug, PartialEq, Eq)] +pub(crate) enum SharedPrefix { + Crate, + Module, +} + +#[cfg(test)] +mod test { + use super::*; + use rustc_span::DUMMY_SP; + + // Parse the path part of an import. This parser is not robust and is only + // suitable for use in a test harness. + fn parse_use_tree(s: &str) -> UseTree { + use std::iter::Peekable; + use std::mem::swap; + use std::str::Chars; + + struct Parser<'a> { + input: Peekable>, + } + + impl<'a> Parser<'a> { + fn bump(&mut self) { + self.input.next().unwrap(); + } + + fn eat(&mut self, c: char) { + assert!(self.input.next().unwrap() == c); + } + + fn push_segment( + result: &mut Vec, + buf: &mut String, + alias_buf: &mut Option, + ) { + if !buf.is_empty() { + let mut alias = None; + swap(alias_buf, &mut alias); + + match buf.as_ref() { + "self" => { + result.push(UseSegment::Slf(alias)); + *buf = String::new(); + *alias_buf = None; + } + "super" => { + result.push(UseSegment::Super(alias)); + *buf = String::new(); + *alias_buf = None; + } + "crate" => { + result.push(UseSegment::Crate(alias)); + *buf = String::new(); + *alias_buf = None; + } + _ => { + let mut name = String::new(); + swap(buf, &mut name); + result.push(UseSegment::Ident(name, alias)); + } + } + } + } + + fn parse_in_list(&mut self) -> UseTree { + let mut result = vec![]; + let mut buf = String::new(); + let mut alias_buf = None; + while let Some(&c) = self.input.peek() { + match c { + '{' => { + assert!(buf.is_empty()); + self.bump(); + result.push(UseSegment::List(self.parse_list())); + self.eat('}'); + } + '*' => { + assert!(buf.is_empty()); + self.bump(); + result.push(UseSegment::Glob); + } + ':' => { + self.bump(); + self.eat(':'); + Self::push_segment(&mut result, &mut buf, &mut alias_buf); + } + '}' | ',' => { + Self::push_segment(&mut result, &mut buf, &mut alias_buf); + return UseTree { + path: result, + span: DUMMY_SP, + list_item: None, + visibility: None, + attrs: None, + }; + } + ' ' => { + self.bump(); + self.eat('a'); + self.eat('s'); + self.eat(' '); + alias_buf = Some(String::new()); + } + c => { + self.bump(); + if let Some(ref mut buf) = alias_buf { + buf.push(c); + } else { + buf.push(c); + } + } + } + } + Self::push_segment(&mut result, &mut buf, &mut alias_buf); + UseTree { + path: result, + span: DUMMY_SP, + list_item: None, + visibility: None, + attrs: None, + } + } + + fn parse_list(&mut self) -> Vec { + let mut result = vec![]; + loop { + match self.input.peek().unwrap() { + ',' | ' ' => self.bump(), + '}' => { + return result; + } + _ => result.push(self.parse_in_list()), + } + } + } } - None => false, + + let mut parser = Parser { + input: s.chars().peekable(), + }; + parser.parse_in_list() + } + + macro_rules! parse_use_trees { + ($($s:expr),* $(,)*) => { + vec![ + $(parse_use_tree($s),)* + ] + } + } + + macro_rules! test_merge { + ($by:ident, [$($input:expr),* $(,)*], [$($output:expr),* $(,)*]) => { + assert_eq!( + merge_use_trees(parse_use_trees!($($input,)*), SharedPrefix::$by), + parse_use_trees!($($output,)*), + ); + } + } + + #[test] + fn test_use_tree_merge_crate() { + test_merge!( + Crate, + ["a::b::{c, d}", "a::b::{e, f}"], + ["a::b::{c, d, e, f}"] + ); + test_merge!(Crate, ["a::b::c", "a::b"], ["a::{b, b::c}"]); + test_merge!(Crate, ["a::b", "a::b"], ["a::b"]); + test_merge!(Crate, ["a", "a::b", "a::b::c"], ["a::{self, b, b::c}"]); + test_merge!( + Crate, + ["a", "a::b", "a::b::c", "a::b::c::d"], + ["a::{self, b, b::{c, c::d}}"] + ); + test_merge!( + Crate, + ["a", "a::b", "a::b::c", "a::b"], + ["a::{self, b, b::c}"] + ); + test_merge!( + Crate, + ["a::{b::{self, c}, d::e}", "a::d::f"], + ["a::{b::{self, c}, d::{e, f}}"] + ); + test_merge!( + Crate, + ["a::d::f", "a::{b::{self, c}, d::e}"], + ["a::{b::{self, c}, d::{e, f}}"] + ); + test_merge!( + Crate, + ["a::{c, d, b}", "a::{d, e, b, a, f}", "a::{f, g, c}"], + ["a::{a, b, c, d, e, f, g}"] + ); + test_merge!( + Crate, + ["a::{self}", "b::{self as foo}"], + ["a::{self}", "b::{self as foo}"] + ); + } + + #[test] + fn test_use_tree_merge_module() { + test_merge!( + Module, + ["foo::b", "foo::{a, c, d::e}"], + ["foo::{a, b, c}", "foo::d::e"] + ); + + test_merge!( + Module, + ["foo::{a::b, a::c, d::e, d::f}"], + ["foo::a::{b, c}", "foo::d::{e, f}"] + ); + } + + #[test] + fn test_flatten_use_trees() { + assert_eq!( + flatten_use_trees(parse_use_trees!["foo::{a::{b, c}, d::e}"]), + parse_use_trees!["foo::a::b", "foo::a::c", "foo::d::e"] + ); + + assert_eq!( + flatten_use_trees(parse_use_trees!["foo::{self, a, b::{c, d}, e::*}"]), + parse_use_trees![ + "foo::{self}", + "foo::a", + "foo::b::c", + "foo::b::d", + "foo::e::*" + ] + ); + } + + #[test] + fn test_use_tree_flatten() { + assert_eq!( + parse_use_tree("a::b::{c, d, e, f}").flatten(), + parse_use_trees!("a::b::c", "a::b::d", "a::b::e", "a::b::f",) + ); + + assert_eq!( + parse_use_tree("a::b::{c::{d, e, f}, g, h::{i, j, k}}").flatten(), + parse_use_trees![ + "a::b::c::d", + "a::b::c::e", + "a::b::c::f", + "a::b::g", + "a::b::h::i", + "a::b::h::j", + "a::b::h::k", + ] + ); + } + + #[test] + fn test_use_tree_normalize() { + assert_eq!(parse_use_tree("a::self").normalize(), parse_use_tree("a")); + assert_eq!( + parse_use_tree("a::self as foo").normalize(), + parse_use_tree("a as foo") + ); + assert_eq!( + parse_use_tree("a::{self}").normalize(), + parse_use_tree("a::{self}") + ); + assert_eq!(parse_use_tree("a::{b}").normalize(), parse_use_tree("a::b")); + assert_eq!( + parse_use_tree("a::{b, c::self}").normalize(), + parse_use_tree("a::{b, c}") + ); + assert_eq!( + parse_use_tree("a::{b as bar, c::self}").normalize(), + parse_use_tree("a::{b as bar, c}") + ); + } + + #[test] + fn test_use_tree_ord() { + assert!(parse_use_tree("a").normalize() < parse_use_tree("aa").normalize()); + assert!(parse_use_tree("a").normalize() < parse_use_tree("a::a").normalize()); + assert!(parse_use_tree("a").normalize() < parse_use_tree("*").normalize()); + assert!(parse_use_tree("a").normalize() < parse_use_tree("{a, b}").normalize()); + assert!(parse_use_tree("*").normalize() < parse_use_tree("{a, b}").normalize()); + + assert!( + parse_use_tree("aaaaaaaaaaaaaaa::{bb, cc, dddddddd}").normalize() + < parse_use_tree("aaaaaaaaaaaaaaa::{bb, cc, ddddddddd}").normalize() + ); + assert!( + parse_use_tree("serde::de::{Deserialize}").normalize() + < parse_use_tree("serde_json").normalize() + ); + assert!(parse_use_tree("a::b::c").normalize() < parse_use_tree("a::b::*").normalize()); + assert!( + parse_use_tree("foo::{Bar, Baz}").normalize() + < parse_use_tree("{Bar, Baz}").normalize() + ); + + assert!( + parse_use_tree("foo::{qux as bar}").normalize() + < parse_use_tree("foo::{self as bar}").normalize() + ); + assert!( + parse_use_tree("foo::{qux as bar}").normalize() + < parse_use_tree("foo::{baz, qux as bar}").normalize() + ); + assert!( + parse_use_tree("foo::{self as bar, baz}").normalize() + < parse_use_tree("foo::{baz, qux as bar}").normalize() + ); + + assert!(parse_use_tree("foo").normalize() < parse_use_tree("Foo").normalize()); + assert!(parse_use_tree("foo").normalize() < parse_use_tree("foo::Bar").normalize()); + + assert!( + parse_use_tree("std::cmp::{d, c, b, a}").normalize() + < parse_use_tree("std::cmp::{b, e, g, f}").normalize() + ); } }