Use RefCell for RewriteContext fields

src/chains.rs

@@ -251,7 +251,7 @@ pub fn rewrite_chain(expr: &ast::Expr, context: &RewriteContext, shape: Shape) -
         Cow::from("")
     } else {
         // Use new lines.
-        if context.force_one_line_chain {
+        if *context.force_one_line_chain.borrow() {
             return None;
         }
         nested_shape.indent.to_string_with_newline(context.config)

src/rewrite.rs

@@ -17,6 +17,8 @@ use config::{Config, IndentStyle};
 use shape::Shape;
 use visitor::SnippetProvider;
 
+use std::cell::RefCell;
+
 pub trait Rewrite {
     /// Rewrite self into shape.
     fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String>;
@@ -29,12 +31,12 @@ pub struct RewriteContext<'a> {
     pub config: &'a Config,
     pub inside_macro: bool,
     // Force block indent style even if we are using visual indent style.
-    pub use_block: bool,
+    pub use_block: RefCell<bool>,
     // When `format_if_else_cond_comment` is true, unindent the comment on top
     // of the `else` or `else if`.
     pub is_if_else_block: bool,
     // When rewriting chain, veto going multi line except the last element
-    pub force_one_line_chain: bool,
+    pub force_one_line_chain: RefCell<bool>,
     pub snippet_provider: &'a SnippetProvider<'a>,
 }
 
@@ -45,7 +47,7 @@ impl<'a> RewriteContext<'a> {
 
     /// Return true if we should use block indent style for rewriting function call.
     pub fn use_block_indent(&self) -> bool {
-        self.config.indent_style() == IndentStyle::Block || self.use_block
+        self.config.indent_style() == IndentStyle::Block || *self.use_block.borrow()
     }
 
     pub fn budget(&self, used_width: usize) -> usize {

src/visitor.rs

@@ -26,6 +26,8 @@ use shape::{Indent, Shape};
 use spanned::Spanned;
 use utils::{self, contains_skip, count_newlines, inner_attributes, mk_sp, ptr_vec_to_ref_vec};
 
+use std::cell::RefCell;
+
 /// Creates a string slice corresponding to the specified span.
 pub struct SnippetProvider<'a> {
     /// A pointer to the content of the file we are formatting.
@@ -691,9 +693,9 @@ impl<'b, 'a: 'b> FmtVisitor<'a> {
             codemap: self.codemap,
             config: self.config,
             inside_macro: false,
-            use_block: false,
+            use_block: RefCell::new(false),
             is_if_else_block: false,
-            force_one_line_chain: false,
+            force_one_line_chain: RefCell::new(false),
             snippet_provider: self.snippet_provider,
         }
     }