Merge pull request #1968 from topecongiro/issue-1967

Reorder use items inside blocks

Author: nrc

src/expr.rs

@@ -34,7 +34,7 @@ use string::{rewrite_string, StringFormat};
 use types::{can_be_overflowed_type, rewrite_path, PathContext};
 use utils::{binary_search, colon_spaces, contains_skip, extra_offset, first_line_width,
             inner_attributes, last_line_extendable, last_line_width, left_most_sub_expr, mk_sp,
-            outer_attributes, paren_overhead, semicolon_for_stmt, stmt_expr,
+            outer_attributes, paren_overhead, ptr_vec_to_ref_vec, semicolon_for_stmt, stmt_expr,
             trimmed_last_line_width, wrap_str};
 use vertical::rewrite_with_alignment;
 use visitor::FmtVisitor;
@@ -86,7 +86,7 @@ pub fn format_expr(
             rewrite_call_with_binary_search(
                 context,
                 &**callee,
-                &args.iter().map(|x| &**x).collect::<Vec<_>>()[..],
+                &ptr_vec_to_ref_vec(&args),
                 inner_span,
                 shape,
             )
@@ -114,12 +114,9 @@ pub fn format_expr(
             expr.span,
             shape,
         ),
-        ast::ExprKind::Tup(ref items) => rewrite_tuple(
-            context,
-            &items.iter().map(|x| &**x).collect::<Vec<_>>()[..],
-            expr.span,
-            shape,
-        ),
+        ast::ExprKind::Tup(ref items) => {
+            rewrite_tuple(context, &ptr_vec_to_ref_vec(&items), expr.span, shape)
+        }
         ast::ExprKind::If(..) |
         ast::ExprKind::IfLet(..) |
         ast::ExprKind::ForLoop(..) |
@@ -2094,7 +2091,7 @@ pub fn rewrite_call(
     rewrite_call_inner(
         context,
         callee,
-        &args.iter().map(|x| &**x).collect::<Vec<_>>(),
+        &ptr_vec_to_ref_vec(&args),
         span,
         shape,
         context.config.fn_call_width(),

src/imports.rs

@@ -10,7 +10,7 @@
 
 use std::cmp::Ordering;
 
-use syntax::{ast, ptr};
+use syntax::ast;
 use syntax::codemap::{BytePos, Span};
 
 use {Shape, Spanned};
@@ -216,7 +216,7 @@ fn rewrite_import(
 
 fn rewrite_imports(
     context: &RewriteContext,
-    use_items: &[ptr::P<ast::Item>],
+    use_items: &[&ast::Item],
     shape: Shape,
     span: Span,
 ) -> Option<String> {
@@ -275,7 +275,7 @@ fn rewrite_imports(
 }
 
 impl<'a> FmtVisitor<'a> {
-    pub fn format_imports(&mut self, use_items: &[ptr::P<ast::Item>]) {
+    pub fn format_imports(&mut self, use_items: &[&ast::Item]) {
         if use_items.is_empty() {
             return;
         }

src/types.rs

@@ -727,7 +727,7 @@ impl Rewrite for ast::Ty {
             }
             ast::TyKind::Tup(ref items) => rewrite_tuple(
                 context,
-                &items.iter().map(|x| &**x).collect::<Vec<_>>()[..],
+                &::utils::ptr_vec_to_ref_vec(&items),
                 self.span,
                 shape,
             ),

src/utils.rs

@@ -11,7 +11,7 @@
 use std::borrow::Cow;
 use std::cmp::Ordering;
 
-use syntax::abi;
+use syntax::{abi, ptr};
 use syntax::ast::{self, Attribute, MetaItem, MetaItemKind, NestedMetaItem, NestedMetaItemKind,
                   Path, Visibility};
 use syntax::codemap::{BytePos, Span, NO_EXPANSION};
@@ -97,6 +97,12 @@ pub fn format_abi(abi: abi::Abi, explicit_abi: bool) -> Cow<'static, str> {
     }
 }
 
+#[inline]
+// Transform `Vec<syntax::ptr::P<T>>` into `Vec<&T>`
+pub fn ptr_vec_to_ref_vec<T>(vec: &[ptr::P<T>]) -> Vec<&T> {
+    vec.iter().map(|x| &**x).collect::<Vec<_>>()
+}
+
 #[inline]
 pub fn filter_attributes(attrs: &[ast::Attribute], style: ast::AttrStyle) -> Vec<ast::Attribute> {
     attrs

src/visitor.rs

@@ -11,7 +11,7 @@
 use std::cmp;
 
 use strings::string_buffer::StringBuffer;
-use syntax::{ast, ptr, visit};
+use syntax::{ast, visit};
 use syntax::attr::HasAttrs;
 use syntax::codemap::{self, BytePos, CodeMap, Pos, Span};
 use syntax::parse::ParseSess;
@@ -30,7 +30,7 @@ use lists::{itemize_list, write_list, DefinitiveListTactic, ListFormatting, Sepa
 use macros::{rewrite_macro, MacroPosition};
 use regex::Regex;
 use rewrite::{Rewrite, RewriteContext};
-use utils::{self, contains_skip, inner_attributes, mk_sp};
+use utils::{self, contains_skip, inner_attributes, mk_sp, ptr_vec_to_ref_vec};
 
 fn is_use_item(item: &ast::Item) -> bool {
     match item.node {
@@ -152,9 +152,7 @@ impl<'a> FmtVisitor<'a> {
             self.visit_attrs(attrs, ast::AttrStyle::Inner);
         }
 
-        for stmt in &b.stmts {
-            self.visit_stmt(stmt)
-        }
+        self.walk_block_stmts(b);
 
         if !b.stmts.is_empty() {
             if let Some(expr) = utils::stmt_expr(&b.stmts[b.stmts.len() - 1]) {
@@ -641,12 +639,7 @@ impl<'a> FmtVisitor<'a> {
         false
     }
 
-    fn reorder_items<F>(
-        &mut self,
-        items_left: &[ptr::P<ast::Item>],
-        is_item: &F,
-        in_group: bool,
-    ) -> usize
+    fn reorder_items<F>(&mut self, items_left: &[&ast::Item], is_item: &F, in_group: bool) -> usize
     where
         F: Fn(&ast::Item) -> bool,
     {
@@ -679,8 +672,7 @@ impl<'a> FmtVisitor<'a> {
         item_length
     }
 
-    fn walk_mod_items(&mut self, m: &ast::Mod) {
-        let mut items_left: &[ptr::P<ast::Item>] = &m.items;
+    fn walk_items(&mut self, mut items_left: &[&ast::Item]) {
         while !items_left.is_empty() {
             // If the next item is a `use` declaration, then extract it and any subsequent `use`s
             // to be potentially reordered within `format_imports`. Otherwise, just format the
@@ -711,6 +703,43 @@ impl<'a> FmtVisitor<'a> {
         }
     }
 
+    fn walk_mod_items(&mut self, m: &ast::Mod) {
+        self.walk_items(&ptr_vec_to_ref_vec(&m.items));
+    }
+
+    fn walk_stmts(&mut self, stmts: &[ast::Stmt]) {
+        fn to_stmt_item(stmt: &ast::Stmt) -> Option<&ast::Item> {
+            match stmt.node {
+                ast::StmtKind::Item(ref item) => Some(&**item),
+                _ => None,
+            }
+        }
+
+        if stmts.is_empty() {
+            return;
+        }
+
+        // Extract leading `use ...;`.
+        let items: Vec<_> = stmts
+            .iter()
+            .take_while(|stmt| to_stmt_item(stmt).is_some())
+            .filter_map(|stmt| to_stmt_item(stmt))
+            .take_while(|item| is_use_item(item))
+            .collect();
+
+        if items.is_empty() {
+            self.visit_stmt(&stmts[0]);
+            self.walk_stmts(&stmts[1..]);
+        } else {
+            self.walk_items(&items);
+            self.walk_stmts(&stmts[items.len()..]);
+        }
+    }
+
+    fn walk_block_stmts(&mut self, b: &ast::Block) {
+        self.walk_stmts(&b.stmts)
+    }
+
     fn format_mod(
         &mut self,
         m: &ast::Mod,

tests/source/configs-reorder_imports-true.rs

@@ -5,3 +5,15 @@ use lorem;
 use ipsum;
 use dolor;
 use sit;
+
+fn foo() {
+    use C;
+    use B;
+    use A;
+
+    bar();
+
+    use F;
+    use E;
+    use D;
+}

tests/target/configs-reorder_imports-true.rs

@@ -5,3 +5,15 @@ use dolor;
 use ipsum;
 use lorem;
 use sit;
+
+fn foo() {
+    use A;
+    use B;
+    use C;
+
+    bar();
+
+    use D;
+    use E;
+    use F;
+}