X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=src%2Fexpr.rs;h=72cf618dca546fc7c0213013d2340ec4dd989161;hb=caefd218c9f6c43493c28c5cc4ea8828c494830e;hp=f23eb617e9d9482d66799e7e91d44afe3f85822b;hpb=8674ab9a4299263c0980613283ae5efb0ffbc001;p=rust.git

diff --git a/src/expr.rs b/src/expr.rs
index f23eb617e9d..72cf618dca5 100644
--- a/src/expr.rs
+++ b/src/expr.rs
@@ -31,6 +31,7 @@
 use macros::{rewrite_macro, MacroArg, MacroPosition};
 use matches::rewrite_match;
 use overflow;
+use pairs::{rewrite_all_pairs, rewrite_pair, PairParts};
 use patterns::{can_be_overflowed_pat, is_short_pattern, TuplePatField};
 use rewrite::{Rewrite, RewriteContext};
 use shape::{Indent, Shape};
@@ -38,9 +39,9 @@
 use string::{rewrite_string, StringFormat};
 use types::{can_be_overflowed_type, rewrite_path, PathContext};
 use utils::{
-    colon_spaces, contains_skip, count_newlines, first_line_width, inner_attributes,
-    last_line_extendable, last_line_width, mk_sp, outer_attributes, ptr_vec_to_ref_vec,
-    semicolon_for_stmt, wrap_str,
+    colon_spaces, contains_skip, count_newlines, first_line_ends_with, first_line_width,
+    inner_attributes, last_line_extendable, last_line_width, mk_sp, outer_attributes,
+    ptr_vec_to_ref_vec, semicolon_for_stmt, wrap_str,
 };
 use vertical::rewrite_with_alignment;
 use visitor::FmtVisitor;
@@ -88,11 +89,11 @@ pub fn format_expr(
         ast::ExprKind::Paren(ref subexpr) => rewrite_paren(context, subexpr, shape, expr.span),
         ast::ExprKind::Binary(op, ref lhs, ref rhs) => {
             // FIXME: format comments between operands and operator
-            rewrite_simple_binaries(context, expr, shape, op).or_else(|| {
+            rewrite_all_pairs(expr, shape, context).or_else(|| {
                 rewrite_pair(
                     &**lhs,
                     &**rhs,
-                    PairParts::new("", &format!(" {} ", context.snippet(op.span)), ""),
+                    PairParts::infix(&format!(" {} ", context.snippet(op.span))),
                     context,
                     shape,
                     context.config.binop_separator(),
@@ -124,7 +125,7 @@ pub fn format_expr(
                     if is_unsafe_block(block) {
                         rewrite_block(block, Some(&expr.attrs), opt_label, context, shape)
                     } else if let rw @ Some(_) =
-                        rewrite_empty_block(context, block, Some(&expr.attrs), "", shape)
+                        rewrite_empty_block(context, block, Some(&expr.attrs), opt_label, "", shape)
                     {
                         // Rewrite block without trying to put it in a single line.
                         rw
@@ -136,6 +137,7 @@ pub fn format_expr(
                             &prefix,
                             block,
                             Some(&expr.attrs),
+                            opt_label,
                             shape,
                             true,
                         )
@@ -182,9 +184,9 @@ pub fn format_expr(
         } else {
             Some("yield".to_string())
         },
-        ast::ExprKind::Closure(capture, movability, ref fn_decl, ref body, _) => {
+        ast::ExprKind::Closure(capture, asyncness, movability, ref fn_decl, ref body, _) => {
             closures::rewrite_closure(
-                capture, movability, fn_decl, body, expr.span, context, shape,
+                capture, asyncness, movability, fn_decl, body, expr.span, context, shape,
             )
         }
         ast::ExprKind::Try(..) | ast::ExprKind::Field(..) | ast::ExprKind::MethodCall(..) => {
@@ -210,7 +212,7 @@ pub fn format_expr(
         ast::ExprKind::Cast(ref expr, ref ty) => rewrite_pair(
             &**expr,
             &**ty,
-            PairParts::new("", " as ", ""),
+            PairParts::infix(" as "),
             context,
             shape,
             SeparatorPlace::Front,
@@ -218,7 +220,7 @@ pub fn format_expr(
         ast::ExprKind::Type(ref expr, ref ty) => rewrite_pair(
             &**expr,
             &**ty,
-            PairParts::new("", ": ", ""),
+            PairParts::infix(": "),
             context,
             shape,
             SeparatorPlace::Back,
@@ -287,7 +289,7 @@ fn needs_space_after_range(rhs: &ast::Expr) -> bool {
                     rewrite_pair(
                         &*lhs,
                         &*rhs,
-                        PairParts::new("", &sp_delim, ""),
+                        PairParts::infix(&sp_delim),
                         context,
                         shape,
                         context.config.binop_separator(),
@@ -316,9 +318,14 @@ fn needs_space_after_range(rhs: &ast::Expr) -> bool {
         // satisfy our width restrictions.
         ast::ExprKind::InlineAsm(..) => Some(context.snippet(expr.span).to_owned()),
         ast::ExprKind::Catch(ref block) => {
-            if let rw @ Some(_) =
-                rewrite_single_line_block(context, "do catch ", block, Some(&expr.attrs), shape)
-            {
+            if let rw @ Some(_) = rewrite_single_line_block(
+                context,
+                "do catch ",
+                block,
+                Some(&expr.attrs),
+                None,
+                shape,
+            ) {
                 rw
             } else {
                 // 9 = `do catch `
@@ -338,6 +345,38 @@ fn needs_space_after_range(rhs: &ast::Expr) -> bool {
         }
         // FIXME(#2743)
         ast::ExprKind::ObsoleteInPlace(..) => unimplemented!(),
+        ast::ExprKind::Async(capture_by, _node_id, ref block) => {
+            let mover = if capture_by == ast::CaptureBy::Value {
+                "move "
+            } else {
+                ""
+            };
+            if let rw @ Some(_) = rewrite_single_line_block(
+                context,
+                format!("{}{}", "async ", mover).as_str(),
+                block,
+                Some(&expr.attrs),
+                None,
+                shape,
+            ) {
+                rw
+            } else {
+                // 6 = `async `
+                let budget = shape.width.saturating_sub(6);
+                Some(format!(
+                    "{}{}{}",
+                    "async ",
+                    mover,
+                    rewrite_block(
+                        block,
+                        Some(&expr.attrs),
+                        None,
+                        context,
+                        Shape::legacy(budget, shape.indent)
+                    )?
+                ))
+            }
+        }
     };
 
     expr_rw
@@ -353,172 +392,6 @@ fn needs_space_after_range(rhs: &ast::Expr) -> bool {
         })
 }
 
-/// Collect operands that appears in the given binary operator in the opposite order.
-/// e.g. `collect_binary_items(e, ||)` for `a && b || c || d` returns `[d, c, a && b]`.
-fn collect_binary_items<'a>(mut expr: &'a ast::Expr, binop: ast::BinOp) -> Vec<&'a ast::Expr> {
-    let mut result = vec![];
-    let mut prev_lhs = None;
-    loop {
-        match expr.node {
-            ast::ExprKind::Binary(inner_binop, ref lhs, ref rhs)
-                if inner_binop.node == binop.node =>
-            {
-                result.push(&**rhs);
-                expr = lhs;
-                prev_lhs = Some(lhs);
-            }
-            _ => {
-                if let Some(lhs) = prev_lhs {
-                    result.push(lhs);
-                }
-                break;
-            }
-        }
-    }
-    result
-}
-
-/// Rewrites a binary expression whose operands fits within a single line.
-fn rewrite_simple_binaries(
-    context: &RewriteContext,
-    expr: &ast::Expr,
-    shape: Shape,
-    op: ast::BinOp,
-) -> Option<String> {
-    let op_str = context.snippet(op.span);
-
-    // 2 = spaces around a binary operator.
-    let sep_overhead = op_str.len() + 2;
-    let nested_overhead = sep_overhead - 1;
-
-    let nested_shape = (match context.config.indent_style() {
-        IndentStyle::Visual => shape.visual_indent(0),
-        IndentStyle::Block => shape.block_indent(context.config.tab_spaces()),
-    }).with_max_width(context.config);
-    let nested_shape = match context.config.binop_separator() {
-        SeparatorPlace::Back => nested_shape.sub_width(nested_overhead)?,
-        SeparatorPlace::Front => nested_shape.offset_left(nested_overhead)?,
-    };
-
-    let opt_rewrites: Option<Vec<_>> = collect_binary_items(expr, op)
-        .iter()
-        .rev()
-        .map(|e| e.rewrite(context, nested_shape))
-        .collect();
-    if let Some(rewrites) = opt_rewrites {
-        if rewrites.iter().all(|e| ::utils::is_single_line(e)) {
-            let total_width = rewrites.iter().map(|s| s.len()).sum::<usize>()
-                + sep_overhead * (rewrites.len() - 1);
-
-            let sep_str = if total_width <= shape.width {
-                format!(" {} ", op_str)
-            } else {
-                let indent_str = nested_shape.indent.to_string_with_newline(context.config);
-                match context.config.binop_separator() {
-                    SeparatorPlace::Back => format!(" {}{}", op_str.trim_right(), indent_str),
-                    SeparatorPlace::Front => format!("{}{} ", indent_str, op_str.trim_left()),
-                }
-            };
-
-            return wrap_str(rewrites.join(&sep_str), context.config.max_width(), shape);
-        }
-    }
-
-    None
-}
-
-#[derive(new, Clone, Copy)]
-pub struct PairParts<'a> {
-    prefix: &'a str,
-    infix: &'a str,
-    suffix: &'a str,
-}
-
-pub fn rewrite_pair<LHS, RHS>(
-    lhs: &LHS,
-    rhs: &RHS,
-    pp: PairParts,
-    context: &RewriteContext,
-    shape: Shape,
-    separator_place: SeparatorPlace,
-) -> Option<String>
-where
-    LHS: Rewrite,
-    RHS: Rewrite,
-{
-    let lhs_overhead = match separator_place {
-        SeparatorPlace::Back => shape.used_width() + pp.prefix.len() + pp.infix.trim_right().len(),
-        SeparatorPlace::Front => shape.used_width(),
-    };
-    let lhs_shape = Shape {
-        width: context.budget(lhs_overhead),
-        ..shape
-    };
-    let lhs_result = lhs
-        .rewrite(context, lhs_shape)
-        .map(|lhs_str| format!("{}{}", pp.prefix, lhs_str))?;
-
-    // Try to put both lhs and rhs on the same line.
-    let rhs_orig_result = shape
-        .offset_left(last_line_width(&lhs_result) + pp.infix.len())
-        .and_then(|s| s.sub_width(pp.suffix.len()))
-        .and_then(|rhs_shape| rhs.rewrite(context, rhs_shape));
-    if let Some(ref rhs_result) = rhs_orig_result {
-        // If the length of the lhs is equal to or shorter than the tab width or
-        // the rhs looks like block expression, we put the rhs on the same
-        // line with the lhs even if the rhs is multi-lined.
-        let allow_same_line = lhs_result.len() <= context.config.tab_spaces()
-            || rhs_result
-                .lines()
-                .next()
-                .map(|first_line| first_line.ends_with('{'))
-                .unwrap_or(false);
-        if !rhs_result.contains('\n') || allow_same_line {
-            let one_line_width = last_line_width(&lhs_result)
-                + pp.infix.len()
-                + first_line_width(rhs_result)
-                + pp.suffix.len();
-            if one_line_width <= shape.width {
-                return Some(format!(
-                    "{}{}{}{}",
-                    lhs_result, pp.infix, rhs_result, pp.suffix
-                ));
-            }
-        }
-    }
-
-    // We have to use multiple lines.
-    // Re-evaluate the rhs because we have more space now:
-    let mut rhs_shape = match context.config.indent_style() {
-        IndentStyle::Visual => shape
-            .sub_width(pp.suffix.len() + pp.prefix.len())?
-            .visual_indent(pp.prefix.len()),
-        IndentStyle::Block => {
-            // Try to calculate the initial constraint on the right hand side.
-            let rhs_overhead = shape.rhs_overhead(context.config);
-            Shape::indented(shape.indent.block_indent(context.config), context.config)
-                .sub_width(rhs_overhead)?
-        }
-    };
-    let infix = match separator_place {
-        SeparatorPlace::Back => pp.infix.trim_right(),
-        SeparatorPlace::Front => pp.infix.trim_left(),
-    };
-    if separator_place == SeparatorPlace::Front {
-        rhs_shape = rhs_shape.offset_left(infix.len())?;
-    }
-    let rhs_result = rhs.rewrite(context, rhs_shape)?;
-    let indent_str = rhs_shape.indent.to_string_with_newline(context.config);
-    let infix_with_sep = match separator_place {
-        SeparatorPlace::Back => format!("{}{}", infix, indent_str),
-        SeparatorPlace::Front => format!("{}{}", indent_str, infix),
-    };
-    Some(format!(
-        "{}{}{}{}",
-        lhs_result, infix_with_sep, rhs_result, pp.suffix
-    ))
-}
-
 pub fn rewrite_array<T: Rewrite + Spanned + ToExpr>(
     name: &str,
     exprs: &[&T],
@@ -543,16 +416,18 @@ fn rewrite_empty_block(
     context: &RewriteContext,
     block: &ast::Block,
     attrs: Option<&[ast::Attribute]>,
+    label: Option<ast::Label>,
     prefix: &str,
     shape: Shape,
 ) -> Option<String> {
+    let label_str = rewrite_label(label);
     if attrs.map_or(false, |a| !inner_attributes(a).is_empty()) {
         return None;
     }
 
     if block.stmts.is_empty() && !block_contains_comment(block, context.codemap) && shape.width >= 2
     {
-        return Some(format!("{}{{}}", prefix));
+        return Some(format!("{}{}{{}}", prefix, label_str));
     }
 
     // If a block contains only a single-line comment, then leave it on one line.
@@ -565,7 +440,7 @@ fn rewrite_empty_block(
             && !comment_str.starts_with("//")
             && comment_str.len() + 4 <= shape.width
         {
-            return Some(format!("{}{{ {} }}", prefix, comment_str));
+            return Some(format!("{}{}{{ {} }}", prefix, label_str, comment_str));
         }
     }
 
@@ -605,12 +480,14 @@ fn rewrite_single_line_block(
     prefix: &str,
     block: &ast::Block,
     attrs: Option<&[ast::Attribute]>,
+    label: Option<ast::Label>,
     shape: Shape,
 ) -> Option<String> {
     if is_simple_block(block, attrs, context.codemap) {
         let expr_shape = shape.offset_left(last_line_width(prefix))?;
         let expr_str = block.stmts[0].rewrite(context, expr_shape)?;
-        let result = format!("{}{{ {} }}", prefix, expr_str);
+        let label_str = rewrite_label(label);
+        let result = format!("{}{}{{ {} }}", prefix, label_str, expr_str);
         if result.len() <= shape.width && !result.contains('\n') {
             return Some(result);
         }
@@ -623,10 +500,11 @@ pub fn rewrite_block_with_visitor(
     prefix: &str,
     block: &ast::Block,
     attrs: Option<&[ast::Attribute]>,
+    label: Option<ast::Label>,
     shape: Shape,
     has_braces: bool,
 ) -> Option<String> {
-    if let rw @ Some(_) = rewrite_empty_block(context, block, attrs, prefix, shape) {
+    if let rw @ Some(_) = rewrite_empty_block(context, block, attrs, label, prefix, shape) {
         return rw;
     }
 
@@ -643,8 +521,9 @@ pub fn rewrite_block_with_visitor(
     }
 
     let inner_attrs = attrs.map(inner_attributes);
+    let label_str = rewrite_label(label);
     visitor.visit_block(block, inner_attrs.as_ref().map(|a| &**a), has_braces);
-    Some(format!("{}{}", prefix, visitor.buffer))
+    Some(format!("{}{}{}", prefix, label_str, visitor.buffer))
 }
 
 impl Rewrite for ast::Block {
@@ -660,20 +539,20 @@ fn rewrite_block(
     context: &RewriteContext,
     shape: Shape,
 ) -> Option<String> {
-    let unsafe_string = block_prefix(context, block, shape)?;
-    let label_string = rewrite_label(label);
-    let prefix = format!("{}{}", unsafe_string, label_string);
+    let prefix = block_prefix(context, block, shape)?;
 
     // shape.width is used only for the single line case: either the empty block `{}`,
     // or an unsafe expression `unsafe { e }`.
-    if let rw @ Some(_) = rewrite_empty_block(context, block, attrs, &prefix, shape) {
+    if let rw @ Some(_) = rewrite_empty_block(context, block, attrs, label, &prefix, shape) {
         return rw;
     }
 
-    let result = rewrite_block_with_visitor(context, &prefix, block, attrs, shape, true);
+    let result = rewrite_block_with_visitor(context, &prefix, block, attrs, label, shape, true);
     if let Some(ref result_str) = result {
         if result_str.lines().count() <= 3 {
-            if let rw @ Some(_) = rewrite_single_line_block(context, &prefix, block, attrs, shape) {
+            if let rw @ Some(_) =
+                rewrite_single_line_block(context, &prefix, block, attrs, label, shape)
+            {
                 return rw;
             }
         }
@@ -1014,16 +893,16 @@ fn rewrite_cond(
             && context
                 .config
                 .width_heuristics()
-                .single_line_if_else_max_width > 0
+                .single_line_if_else_max_width
+                > 0
         {
             let trial = self.rewrite_single_line(&pat_expr_string, context, shape.width);
 
             if let Some(cond_str) = trial {
-                if cond_str.len()
-                    <= context
-                        .config
-                        .width_heuristics()
-                        .single_line_if_else_max_width
+                if cond_str.len() <= context
+                    .config
+                    .width_heuristics()
+                    .single_line_if_else_max_width
                 {
                     return Some((cond_str, 0));
                 }
@@ -1125,7 +1004,7 @@ fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
         let block_str = {
             let old_val = context.is_if_else_block.replace(self.else_block.is_some());
             let result =
-                rewrite_block_with_visitor(context, "", self.block, None, block_shape, true);
+                rewrite_block_with_visitor(context, "", self.block, None, None, block_shape, true);
             context.is_if_else_block.replace(old_val);
             result?
         };
@@ -1326,6 +1205,7 @@ pub fn rewrite_multiple_patterns(
         shape,
         ends_with_newline: false,
         preserve_newline: false,
+        nested: false,
         config: context.config,
     };
     write_list(&items, &fmt)
@@ -1362,8 +1242,7 @@ fn rewrite_string_lit(context: &RewriteContext, span: Span, shape: Shape) -> Opt
                             new_indent.to_string(context.config),
                             line.trim_left()
                         )
-                    })
-                    .collect::<Vec<_>>()
+                    }).collect::<Vec<_>>()
                     .join("\n")
                     .trim_left(),
             );
@@ -1379,7 +1258,6 @@ fn rewrite_string_lit(context: &RewriteContext, span: Span, shape: Shape) -> Opt
     rewrite_string(
         str_lit,
         &StringFormat::new(shape.visual_indent(0), context.config),
-        None,
     )
 }
 
@@ -1803,7 +1681,7 @@ pub fn rewrite_field(
     if !attrs_str.is_empty() {
         attrs_str.push_str(&shape.indent.to_string_with_newline(context.config));
     };
-    let name = &field.ident.name.to_string();
+    let name = context.snippet(field.ident.span);
     if field.is_shorthand {
         Some(attrs_str + &name)
     } else {
@@ -1890,6 +1768,7 @@ fn rewrite_tuple_in_visual_indent_style<'a, T>(
         shape,
         ends_with_newline: false,
         preserve_newline: false,
+        nested: false,
         config: context.config,
     };
     let list_str = write_list(&item_vec, &fmt)?;
@@ -2000,8 +1879,8 @@ fn rewrite_assignment(
 pub enum RhsTactics {
     /// Use heuristics.
     Default,
-    /// Put the rhs on the next line if it uses multiple line.
-    ForceNextLine,
+    /// Put the rhs on the next line if it uses multiple line, without extra indentation.
+    ForceNextLineWithoutIndent,
 }
 
 // The left hand side must contain everything up to, and including, the
@@ -2058,11 +1937,12 @@ fn choose_rhs<R: Rewrite>(
         _ => {
             // Expression did not fit on the same line as the identifier.
             // Try splitting the line and see if that works better.
-            let new_shape =
-                Shape::indented(shape.indent.block_indent(context.config), context.config)
-                    .sub_width(shape.rhs_overhead(context.config))?;
+            let new_shape = shape_from_rhs_tactic(context, shape, rhs_tactics)?;
             let new_rhs = expr.rewrite(context, new_shape);
-            let new_indent_str = &new_shape.indent.to_string_with_newline(context.config);
+            let new_indent_str = &shape
+                .indent
+                .block_indent(context.config)
+                .to_string_with_newline(context.config);
 
             match (orig_rhs, new_rhs) {
                 (Some(ref orig_rhs), Some(ref new_rhs))
@@ -2078,16 +1958,33 @@ fn choose_rhs<R: Rewrite>(
                 }
                 (None, Some(ref new_rhs)) => Some(format!("{}{}", new_indent_str, new_rhs)),
                 (None, None) => None,
-                (Some(ref orig_rhs), _) => Some(format!(" {}", orig_rhs)),
+                (Some(orig_rhs), _) => Some(format!(" {}", orig_rhs)),
             }
         }
     }
 }
 
+fn shape_from_rhs_tactic(
+    context: &RewriteContext,
+    shape: Shape,
+    rhs_tactic: RhsTactics,
+) -> Option<Shape> {
+    match rhs_tactic {
+        RhsTactics::ForceNextLineWithoutIndent => Some(shape.with_max_width(context.config)),
+        RhsTactics::Default => {
+            Shape::indented(shape.indent.block_indent(context.config), context.config)
+                .sub_width(shape.rhs_overhead(context.config))
+        }
+    }
+}
+
 pub fn prefer_next_line(orig_rhs: &str, next_line_rhs: &str, rhs_tactics: RhsTactics) -> bool {
-    rhs_tactics == RhsTactics::ForceNextLine
+    rhs_tactics == RhsTactics::ForceNextLineWithoutIndent
         || !next_line_rhs.contains('\n')
         || count_newlines(orig_rhs) > count_newlines(next_line_rhs) + 1
+        || first_line_ends_with(orig_rhs, '(') && !first_line_ends_with(next_line_rhs, '(')
+        || first_line_ends_with(orig_rhs, '{') && !first_line_ends_with(next_line_rhs, '{')
+        || first_line_ends_with(orig_rhs, '[') && !first_line_ends_with(next_line_rhs, '[')
 }
 
 fn rewrite_expr_addrof(