Add syntux module (#3880)

Author: topecongiro

Cargo.toml

@@ -56,6 +56,7 @@ ignore = "0.4.6"
 annotate-snippets = { version = "0.6", features = ["ansi_term"] }
 structopt = "0.3"
 rustfmt-config_proc_macro = { version = "0.2", path = "config_proc_macro" }
+lazy_static = "1.0.0"
 
 # A noop dependency that changes in the Rust repository, it's a bit of a hack.
 # See the `src/tools/rustc-workspace-hack/README.md` file in `rust-lang/rust`
@@ -74,5 +75,3 @@ version = "610.0.0"
 package = "rustc-ap-syntax_pos"
 version = "610.0.0"
 
-[dev-dependencies]
-lazy_static = "1.0.0"

src/closures.rs

@@ -43,7 +43,7 @@ pub(crate) fn rewrite_closure(
 
     if let ast::ExprKind::Block(ref block, _) = body.kind {
         // The body of the closure is an empty block.
-        if block.stmts.is_empty() && !block_contains_comment(block, context.source_map) {
+        if block.stmts.is_empty() && !block_contains_comment(context, block) {
             return body
                 .rewrite(context, shape)
                 .map(|s| format!("{} {}", prefix, s));
@@ -112,7 +112,7 @@ fn needs_block(block: &ast::Block, prefix: &str, context: &RewriteContext<'_>) -
     is_unsafe_block(block)
         || block.stmts.len() > 1
         || has_attributes
-        || block_contains_comment(block, context.source_map)
+        || block_contains_comment(context, block)
         || prefix.contains('\n')
 }
 
@@ -304,7 +304,7 @@ pub(crate) fn rewrite_last_closure(
             ast::ExprKind::Block(ref block, _)
                 if !is_unsafe_block(block)
                     && !context.inside_macro()
-                    && is_simple_block(block, Some(&body.attrs), context.source_map) =>
+                    && is_simple_block(context, block, Some(&body.attrs)) =>
             {
                 stmt_expr(&block.stmts[0]).unwrap_or(body)
             }

src/comment.rs

@@ -1556,10 +1556,10 @@ pub(crate) fn recover_comment_removed(
         // We missed some comments. Warn and keep the original text.
         if context.config.error_on_unformatted() {
             context.report.append(
-                context.source_map.span_to_filename(span).into(),
+                context.parse_sess.span_to_filename(span),
                 vec![FormattingError::from_span(
                     span,
-                    &context.source_map,
+                    &context.parse_sess,
                     ErrorKind::LostComment,
                 )],
             );

src/expr.rs

@@ -3,7 +3,7 @@ use std::cmp::min;
 
 use itertools::Itertools;
 use syntax::parse::token::{DelimToken, LitKind};
-use syntax::source_map::{BytePos, SourceMap, Span};
+use syntax::source_map::{BytePos, Span};
 use syntax::{ast, ptr};
 
 use crate::chains::rewrite_chain;
@@ -430,7 +430,7 @@ fn rewrite_empty_block(
         return None;
     }
 
-    if !block_contains_comment(block, context.source_map) && shape.width >= 2 {
+    if !block_contains_comment(context, block) && shape.width >= 2 {
         return Some(format!("{}{}{{}}", prefix, label_str));
     }
 
@@ -487,7 +487,7 @@ fn rewrite_single_line_block(
     label: Option<ast::Label>,
     shape: Shape,
 ) -> Option<String> {
-    if is_simple_block(block, attrs, context.source_map) {
+    if is_simple_block(context, block, attrs) {
         let expr_shape = shape.offset_left(last_line_width(prefix))?;
         let expr_str = block.stmts[0].rewrite(context, expr_shape)?;
         let label_str = rewrite_label(label);
@@ -750,8 +750,8 @@ impl<'a> ControlFlow<'a> {
         let fixed_cost = self.keyword.len() + "  {  } else {  }".len();
 
         if let ast::ExprKind::Block(ref else_node, _) = else_block.kind {
-            if !is_simple_block(self.block, None, context.source_map)
-                || !is_simple_block(else_node, None, context.source_map)
+            if !is_simple_block(context, self.block, None)
+                || !is_simple_block(context, else_node, None)
                 || pat_expr_str.contains('\n')
             {
                 return None;
@@ -1134,47 +1134,46 @@ fn extract_comment(span: Span, context: &RewriteContext<'_>, shape: Shape) -> Op
     }
 }
 
-pub(crate) fn block_contains_comment(block: &ast::Block, source_map: &SourceMap) -> bool {
-    let snippet = source_map.span_to_snippet(block.span).unwrap();
-    contains_comment(&snippet)
+pub(crate) fn block_contains_comment(context: &RewriteContext<'_>, block: &ast::Block) -> bool {
+    contains_comment(context.snippet(block.span))
 }
 
 // Checks that a block contains no statements, an expression and no comments or
 // attributes.
 // FIXME: incorrectly returns false when comment is contained completely within
 // the expression.
 pub(crate) fn is_simple_block(
+    context: &RewriteContext<'_>,
     block: &ast::Block,
     attrs: Option<&[ast::Attribute]>,
-    source_map: &SourceMap,
 ) -> bool {
     (block.stmts.len() == 1
         && stmt_is_expr(&block.stmts[0])
-        && !block_contains_comment(block, source_map)
+        && !block_contains_comment(context, block)
         && attrs.map_or(true, |a| a.is_empty()))
 }
 
 /// Checks whether a block contains at most one statement or expression, and no
 /// comments or attributes.
 pub(crate) fn is_simple_block_stmt(
+    context: &RewriteContext<'_>,
     block: &ast::Block,
     attrs: Option<&[ast::Attribute]>,
-    source_map: &SourceMap,
 ) -> bool {
     block.stmts.len() <= 1
-        && !block_contains_comment(block, source_map)
+        && !block_contains_comment(context, block)
         && attrs.map_or(true, |a| a.is_empty())
 }
 
 /// Checks whether a block contains no statements, expressions, comments, or
 /// inner attributes.
 pub(crate) fn is_empty_block(
+    context: &RewriteContext<'_>,
     block: &ast::Block,
     attrs: Option<&[ast::Attribute]>,
-    source_map: &SourceMap,
 ) -> bool {
     block.stmts.is_empty()
-        && !block_contains_comment(block, source_map)
+        && !block_contains_comment(context, block)
         && attrs.map_or(true, |a| inner_attributes(a).is_empty())
 }