diff --git a/src/chains.rs b/src/chains.rs
index bd9f302824b..daf800ace08 100644
--- a/src/chains.rs
+++ b/src/chains.rs
@@ -19,6 +19,7 @@
 // we put each subexpression on a separate, much like the (default) function
 // argument function argument strategy.
 
+use Indent;
 use rewrite::{Rewrite, RewriteContext};
 use utils::{first_line_width, make_indent};
 use expr::rewrite_call;
@@ -30,7 +31,7 @@
 pub fn rewrite_chain(mut expr: &ast::Expr,
                      context: &RewriteContext,
                      width: usize,
-                     offset: usize)
+                     offset: Indent)
                      -> Option<String> {
     let total_span = expr.span;
     let mut subexpr_list = vec![expr];
@@ -116,7 +117,7 @@ pub fn rewrite_chain(mut expr: &ast::Expr,
     let connector = if fits_single_line {
         String::new()
     } else {
-        format!("\n{}", make_indent(indent))
+        format!("\n{}", make_indent(indent, context.config))
     };
 
     let first_connector = if extend {
@@ -145,7 +146,7 @@ fn rewrite_chain_expr(expr: &ast::Expr,
                       span: Span,
                       context: &RewriteContext,
                       width: usize,
-                      offset: usize)
+                      offset: Indent)
                       -> Option<String> {
     match expr.node {
         ast::Expr_::ExprMethodCall(ref method_name, ref types, ref expressions) => {
@@ -179,7 +180,7 @@ fn rewrite_method_call(method_name: ast::Ident,
                        span: Span,
                        context: &RewriteContext,
                        width: usize,
-                       offset: usize)
+                       offset: Indent)
                        -> Option<String> {
     let type_str = if types.is_empty() {
         String::new()
diff --git a/src/comment.rs b/src/comment.rs
index 05117a7cb76..683bf4b650c 100644
--- a/src/comment.rs
+++ b/src/comment.rs
@@ -12,10 +12,17 @@
 
 use std::iter;
 
+use Indent;
+use config::Config;
 use string::{StringFormat, rewrite_string};
 use utils::make_indent;
 
-pub fn rewrite_comment(orig: &str, block_style: bool, width: usize, offset: usize) -> String {
+pub fn rewrite_comment(orig: &str,
+                       block_style: bool,
+                       width: usize,
+                       offset: Indent,
+                       config: &Config)
+                       -> String {
     let s = orig.trim();
 
     // Edge case: block comments. Let's not trim their lines (for now).
@@ -33,11 +40,12 @@ pub fn rewrite_comment(orig: &str, block_style: bool, width: usize, offset: usiz
         line_start: line_start,
         line_end: "",
         width: max_chars,
-        offset: offset + opener.len() - line_start.len(),
+        offset: offset + (opener.len() - line_start.len()),
         trim_end: true,
+        config: config,
     };
 
-    let indent_str = make_indent(offset);
+    let indent_str = make_indent(offset, config);
     let line_breaks = s.chars().filter(|&c| c == '\n').count();
 
     let (_, mut s) = s.lines()
@@ -288,27 +296,32 @@ fn next(&mut self) -> Option<(CodeCharKind, T::Item)> {
 mod test {
     use super::{CharClasses, CodeCharKind, contains_comment, rewrite_comment, FindUncommented};
 
-    // FIXME(#217): prevent string literal from going over the limit.
+    use Indent;
     #[test]
     #[rustfmt_skip]
     fn format_comments() {
-        assert_eq!("/* test */", rewrite_comment(" //test", true, 100, 100));
-        assert_eq!("// comment\n// on a", rewrite_comment("// comment on a", false, 10, 0));
+        let config = Default::default();
+        assert_eq!("/* test */", rewrite_comment(" //test", true, 100, Indent::new(0, 100),
+                                                 &config));
+        assert_eq!("// comment\n// on a", rewrite_comment("// comment on a", false, 10,
+                                                          Indent::new(0, 0), &config));
 
         assert_eq!("//  A multi line comment\n            // between args.",
                    rewrite_comment("//  A multi line comment\n             // between args.",
                                    false,
                                    60,
-                                   12));
+                                   Indent::new(0, 12),
+                                   &config));
 
         let input = "// comment";
         let expected =
             "/* com\n                                                                      \
              * men\n                                                                      \
              * t */";
-        assert_eq!(expected, rewrite_comment(input, true, 9, 69));
+        assert_eq!(expected, rewrite_comment(input, true, 9, Indent::new(0, 69), &config));
 
-        assert_eq!("/* trimmed */", rewrite_comment("/*   trimmed    */", true, 100, 100));
+        assert_eq!("/* trimmed */", rewrite_comment("/*   trimmed    */", true, 100,
+                                                    Indent::new(0, 100), &config));
     }
 
     // This is probably intended to be a non-test fn, but it is not used. I'm
diff --git a/src/config.rs b/src/config.rs
index 2ecee9f98fe..c5b777e1d81 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -246,6 +246,7 @@ pub fn get_docs() -> Vec<ConfigHelpItem> {
     format_strings: bool, "Format string literals, or leave as is",
     chains_overflow_last: bool, "Allow last call in method chain to break the line",
     take_source_hints: bool, "Retain some formatting characteristics from the source code",
+    hard_tabs: bool, "Use tab characters for indentation, spaces for alignment",
 }
 
 impl Default for Config {
@@ -279,6 +280,7 @@ fn default() -> Config {
             format_strings: true,
             chains_overflow_last: true,
             take_source_hints: true,
+            hard_tabs: false,
         }
     }
 }
diff --git a/src/expr.rs b/src/expr.rs
index a91c6c38572..3e8401af8b9 100644
--- a/src/expr.rs
+++ b/src/expr.rs
@@ -11,6 +11,7 @@
 use std::cmp::Ordering;
 use std::borrow::Borrow;
 
+use Indent;
 use rewrite::{Rewrite, RewriteContext};
 use lists::{write_list, itemize_list, ListFormatting, SeparatorTactic, ListTactic};
 use string::{StringFormat, rewrite_string};
@@ -29,7 +30,7 @@
 use syntax::visit::Visitor;
 
 impl Rewrite for ast::Expr {
-    fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Option<String> {
+    fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
         match self.node {
             ast::Expr_::ExprVec(ref expr_vec) => {
                 rewrite_array(expr_vec.iter().map(|e| &**e), self.span, context, width, offset)
@@ -164,7 +165,7 @@ pub fn rewrite_array<'a, I>(expr_iter: I,
                             span: Span,
                             context: &RewriteContext,
                             width: usize,
-                            offset: usize)
+                            offset: Indent)
                             -> Option<String>
     where I: Iterator<Item = &'a ast::Expr>
 {
@@ -201,6 +202,7 @@ pub fn rewrite_array<'a, I>(expr_iter: I,
         h_width: max_item_width,
         v_width: max_item_width,
         ends_with_newline: false,
+        config: context.config,
     };
     let list_str = try_opt!(write_list(&items, &fmt));
 
@@ -215,7 +217,7 @@ fn rewrite_closure(capture: ast::CaptureClause,
                    span: Span,
                    context: &RewriteContext,
                    width: usize,
-                   offset: usize)
+                   offset: Indent)
                    -> Option<String> {
     let mover = if capture == ast::CaptureClause::CaptureByValue {
         "move "
@@ -258,6 +260,7 @@ fn rewrite_closure(capture: ast::CaptureClause,
         h_width: horizontal_budget,
         v_width: budget,
         ends_with_newline: false,
+        config: context.config,
     };
     let list_str = try_opt!(write_list(&arg_items.collect::<Vec<_>>(), &fmt));
     let mut prefix = format!("{}|{}|", mover, list_str);
@@ -265,7 +268,7 @@ fn rewrite_closure(capture: ast::CaptureClause,
     if !ret_str.is_empty() {
         if prefix.contains('\n') {
             prefix.push('\n');
-            prefix.push_str(&make_indent(argument_offset));
+            prefix.push_str(&make_indent(argument_offset, context.config));
         } else {
             prefix.push(' ');
         }
@@ -308,18 +311,18 @@ fn rewrite_closure(capture: ast::CaptureClause,
                            .as_ref()
                            .and_then(|body_expr| {
                                if let ast::Expr_::ExprBlock(ref inner) = body_expr.node {
-                                   Some(inner.rewrite(&context, 2, 0))
+                                   Some(inner.rewrite(&context, 2, Indent::new(0, 0)))
                                } else {
                                    None
                                }
                            })
-                           .unwrap_or_else(|| body.rewrite(&context, 2, 0));
+                           .unwrap_or_else(|| body.rewrite(&context, 2, Indent::new(0, 0)));
 
     Some(format!("{} {}", prefix, try_opt!(body_rewrite)))
 }
 
 impl Rewrite for ast::Block {
-    fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Option<String> {
+    fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
         let user_str = context.snippet(self.span);
         if user_str == "{}" && width >= 2 {
             return Some(user_str);
@@ -341,7 +344,8 @@ fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Opti
                 let prefix = if !trimmed.is_empty() {
                     // 9 = "unsafe  {".len(), 7 = "unsafe ".len()
                     let budget = try_opt!(width.checked_sub(9));
-                    format!("unsafe {} ", rewrite_comment(trimmed, true, budget, offset + 7))
+                    format!("unsafe {} ",
+                            rewrite_comment(trimmed, true, budget, offset + 7, context.config))
                 } else {
                     "unsafe ".to_owned()
                 };
@@ -381,7 +385,7 @@ fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Opti
 
 // FIXME(#18): implement pattern formatting
 impl Rewrite for ast::Pat {
-    fn rewrite(&self, context: &RewriteContext, _: usize, _: usize) -> Option<String> {
+    fn rewrite(&self, context: &RewriteContext, _: usize, _: Indent) -> Option<String> {
         Some(context.snippet(self.span))
     }
 }
@@ -447,7 +451,7 @@ fn new_for(pat: &'a ast::Pat,
 }
 
 impl<'a> Rewrite for Loop<'a> {
-    fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Option<String> {
+    fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
         let label_string = rewrite_label(self.label);
         // 2 = " {".len()
         let inner_width = try_opt!(width.checked_sub(self.keyword.len() + 2 + label_string.len()));
@@ -483,7 +487,7 @@ fn rewrite_range(context: &RewriteContext,
                  left: Option<&ast::Expr>,
                  right: Option<&ast::Expr>,
                  width: usize,
-                 offset: usize)
+                 offset: Indent)
                  -> Option<String> {
     let left_string = match left {
         Some(expr) => {
@@ -513,7 +517,7 @@ fn rewrite_if_else(context: &RewriteContext,
                    else_block_opt: Option<&ast::Expr>,
                    pat: Option<&ast::Pat>,
                    width: usize,
-                   offset: usize,
+                   offset: Indent,
                    allow_single_line: bool)
                    -> Option<String> {
     // 3 = "if ", 2 = " {"
@@ -588,11 +592,11 @@ fn single_line_if_else(context: &RewriteContext,
 
         let new_width = try_opt!(width.checked_sub(pat_expr_str.len() + fixed_cost));
         let if_expr = if_node.expr.as_ref().unwrap();
-        let if_str = try_opt!(if_expr.rewrite(context, new_width, 0));
+        let if_str = try_opt!(if_expr.rewrite(context, new_width, Indent::new(0, 0)));
 
         let new_width = try_opt!(new_width.checked_sub(if_str.len()));
         let else_expr = else_node.expr.as_ref().unwrap();
-        let else_str = try_opt!(else_expr.rewrite(context, new_width, 0));
+        let else_str = try_opt!(else_expr.rewrite(context, new_width, Indent::new(0, 0)));
 
         // FIXME: this check shouldn't be necessary. Rewrites should either fail
         // or wrap to a newline when the object does not fit the width.
@@ -621,7 +625,7 @@ fn rewrite_match(context: &RewriteContext,
                  cond: &ast::Expr,
                  arms: &[ast::Arm],
                  width: usize,
-                 offset: usize)
+                 offset: Indent)
                  -> Option<String> {
     if arms.is_empty() {
         return None;
@@ -634,7 +638,7 @@ fn rewrite_match(context: &RewriteContext,
 
     let nested_context = context.nested_context();
     let arm_indent = nested_context.block_indent + context.overflow_indent;
-    let arm_indent_str = make_indent(arm_indent);
+    let arm_indent_str = make_indent(arm_indent, context.config);
 
     let open_brace_pos = span_after(mk_sp(cond.span.hi, arm_start_pos(&arms[0])),
                                     "{",
@@ -669,7 +673,7 @@ fn rewrite_match(context: &RewriteContext,
         result.push_str(&arm_indent_str);
 
         let arm_str = arm.rewrite(&nested_context,
-                                  context.config.max_width - arm_indent,
+                                  context.config.max_width - arm_indent.width(),
                                   arm_indent);
         if let Some(ref arm_str) = arm_str {
             result.push_str(arm_str);
@@ -684,7 +688,7 @@ fn rewrite_match(context: &RewriteContext,
     // match expression, but meh.
 
     result.push('\n');
-    result.push_str(&make_indent(context.block_indent + context.overflow_indent));
+    result.push_str(&make_indent(context.block_indent + context.overflow_indent, context.config));
     result.push('}');
     Some(result)
 }
@@ -704,9 +708,9 @@ fn arm_end_pos(arm: &ast::Arm) -> BytePos {
 
 // Match arms.
 impl Rewrite for ast::Arm {
-    fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Option<String> {
+    fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
         let &ast::Arm { ref attrs, ref pats, ref guard, ref body } = self;
-        let indent_str = make_indent(offset);
+        let indent_str = make_indent(offset, context.config);
 
         // FIXME this is all a bit grotty, would be nice to abstract out the
         // treatment of attributes.
@@ -734,7 +738,7 @@ fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Opti
                                     .map(|p| {
                                         p.rewrite(context,
                                                   pat_budget,
-                                                  offset + context.config.tab_spaces)
+                                                  offset.block_indent(context.config.tab_spaces))
                                     })
                                     .collect::<Option<Vec<_>>>());
 
@@ -775,7 +779,12 @@ fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Opti
         // Where the next text can start.
         let mut line_start = last_line_width(&pats_str);
         if pats_str.find('\n').is_none() {
-            line_start += offset;
+            line_start += offset.width();
+        }
+
+        let mut line_indent = offset + pats_width;
+        if vertical {
+            line_indent = line_indent.block_indent(context.config.tab_spaces);
         }
 
         let comma = if let ast::ExprBlock(_) = body.node {
@@ -788,7 +797,7 @@ fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Opti
         // 4 = ` => `.len()
         if context.config.max_width > line_start + comma.len() + 4 {
             let budget = context.config.max_width - line_start - comma.len() - 4;
-            if let Some(ref body_str) = body.rewrite(context, budget, line_start + 4) {
+            if let Some(ref body_str) = body.rewrite(context, budget, line_indent + 4) {
                 if first_line_width(body_str) <= budget {
                     return Some(format!("{}{} => {}{}",
                                         attr_str.trim_left(),
@@ -810,7 +819,7 @@ fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Opti
         Some(format!("{}{} =>\n{}{},",
                      attr_str.trim_left(),
                      pats_str,
-                     make_indent(offset + context.config.tab_spaces),
+                     make_indent(offset.block_indent(context.config.tab_spaces), context.config),
                      body_str))
     }
 }
@@ -819,7 +828,7 @@ fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Opti
 fn rewrite_guard(context: &RewriteContext,
                  guard: &Option<ptr::P<ast::Expr>>,
                  width: usize,
-                 offset: usize,
+                 offset: Indent,
                  // The amount of space used up on this line for the pattern in
                  // the arm (excludes offset).
                  pattern_width: usize)
@@ -840,10 +849,11 @@ fn rewrite_guard(context: &RewriteContext,
         if overhead < width {
             let cond_str = guard.rewrite(context,
                                          width - overhead,
-                                         offset + context.config.tab_spaces);
+                                         offset.block_indent(context.config.tab_spaces));
             if let Some(cond_str) = cond_str {
                 return Some(format!("\n{}if {}",
-                                    make_indent(offset + context.config.tab_spaces),
+                                    make_indent(offset.block_indent(context.config.tab_spaces),
+                                                context.config),
                                     cond_str));
             }
         }
@@ -862,7 +872,7 @@ fn rewrite_pat_expr(context: &RewriteContext,
                     // *without* trailing space.
                     connector: &str,
                     width: usize,
-                    offset: usize)
+                    offset: Indent)
                     -> Option<String> {
     let pat_offset = offset + matcher.len();
     let mut result = match pat {
@@ -898,9 +908,11 @@ fn rewrite_pat_expr(context: &RewriteContext,
 
     // The expression won't fit on the current line, jump to next.
     result.push('\n');
-    result.push_str(&make_indent(pat_offset));
+    result.push_str(&make_indent(pat_offset, context.config));
 
-    let expr_rewrite = expr.rewrite(context, context.config.max_width - pat_offset, pat_offset);
+    let expr_rewrite = expr.rewrite(context,
+                                    context.config.max_width - pat_offset.width(),
+                                    pat_offset);
     result.push_str(&&try_opt!(expr_rewrite));
 
     Some(result)
@@ -909,7 +921,7 @@ fn rewrite_pat_expr(context: &RewriteContext,
 fn rewrite_string_lit(context: &RewriteContext,
                       span: Span,
                       width: usize,
-                      offset: usize)
+                      offset: Indent)
                       -> Option<String> {
     if !context.config.format_strings {
         return Some(context.snippet(span));
@@ -923,6 +935,7 @@ fn rewrite_string_lit(context: &RewriteContext,
         width: width,
         offset: offset,
         trim_end: false,
+        config: context.config,
     };
 
     let string_lit = context.snippet(span);
@@ -936,7 +949,7 @@ pub fn rewrite_call<R>(context: &RewriteContext,
                        args: &[ptr::P<ast::Expr>],
                        span: Span,
                        width: usize,
-                       offset: usize)
+                       offset: Indent)
                        -> Option<String>
     where R: Rewrite
 {
@@ -955,7 +968,7 @@ fn rewrite_call_inner<R>(context: &RewriteContext,
                          args: &[ptr::P<ast::Expr>],
                          span: Span,
                          width: usize,
-                         offset: usize)
+                         offset: Indent)
                          -> Result<String, Ordering>
     where R: Rewrite
 {
@@ -1003,7 +1016,7 @@ fn rewrite_call_inner<R>(context: &RewriteContext,
                              span.lo,
                              span.hi);
 
-    let fmt = ListFormatting::for_fn(remaining_width, offset);
+    let fmt = ListFormatting::for_fn(remaining_width, offset, context.config);
     let list_str = match write_list(&items.collect::<Vec<_>>(), &fmt) {
         Some(str) => str,
         None => return Err(Ordering::Less),
@@ -1015,9 +1028,9 @@ fn rewrite_call_inner<R>(context: &RewriteContext,
 fn rewrite_paren(context: &RewriteContext,
                  subexpr: &ast::Expr,
                  width: usize,
-                 offset: usize)
+                 offset: Indent)
                  -> Option<String> {
-    debug!("rewrite_paren, width: {}, offset: {}", width, offset);
+    debug!("rewrite_paren, width: {}, offset: {:?}", width, offset);
     // 1 is for opening paren, 2 is for opening+closing, we want to keep the closing
     // paren on the same line as the subexpr.
     let subexpr_str = subexpr.rewrite(context, try_opt!(width.checked_sub(2)), offset + 1);
@@ -1031,9 +1044,9 @@ fn rewrite_struct_lit<'a>(context: &RewriteContext,
                           base: Option<&'a ast::Expr>,
                           span: Span,
                           width: usize,
-                          offset: usize)
+                          offset: Indent)
                           -> Option<String> {
-    debug!("rewrite_struct_lit: width {}, offset {}", width, offset);
+    debug!("rewrite_struct_lit: width {}, offset {:?}", width, offset);
     assert!(!fields.is_empty() || base.is_some());
 
     enum StructLitField<'a> {
@@ -1054,8 +1067,8 @@ enum StructLitField<'a> {
         StructLitStyle::Block => {
             // If we are all on one line, then we'll ignore the indent, and we
             // have a smaller budget.
-            let indent = context.block_indent + context.config.tab_spaces;
-            let v_budget = context.config.max_width.checked_sub(indent).unwrap_or(0);
+            let indent = context.block_indent.block_indent(context.config.tab_spaces);
+            let v_budget = context.config.max_width.checked_sub(indent.width()).unwrap_or(0);
             (indent, v_budget)
         }
     };
@@ -1121,12 +1134,15 @@ enum StructLitField<'a> {
         h_width: h_budget,
         v_width: v_budget,
         ends_with_newline: false,
+        config: context.config,
     };
     let fields_str = try_opt!(write_list(&items.collect::<Vec<_>>(), &fmt));
 
     let format_on_newline = || {
-        let inner_indent = make_indent(context.block_indent + context.config.tab_spaces);
-        let outer_indent = make_indent(context.block_indent);
+        let inner_indent = make_indent(context.block_indent
+                                              .block_indent(context.config.tab_spaces),
+                                       context.config);
+        let outer_indent = make_indent(context.block_indent, context.config);
         Some(format!("{} {{\n{}{}\n{}}}", path_str, inner_indent, fields_str, outer_indent))
     };
 
@@ -1143,7 +1159,7 @@ enum StructLitField<'a> {
 fn rewrite_field(context: &RewriteContext,
                  field: &ast::Field,
                  width: usize,
-                 offset: usize)
+                 offset: Indent)
                  -> Option<String> {
     let name = &field.ident.node.to_string();
     let overhead = name.len() + 2;
@@ -1156,9 +1172,9 @@ fn rewrite_tuple_lit(context: &RewriteContext,
                      items: &[ptr::P<ast::Expr>],
                      span: Span,
                      width: usize,
-                     offset: usize)
+                     offset: Indent)
                      -> Option<String> {
-    debug!("rewrite_tuple_lit: width: {}, offset: {}", width, offset);
+    debug!("rewrite_tuple_lit: width: {}, offset: {:?}", width, offset);
     let indent = offset + 1;
     // In case of length 1, need a trailing comma
     if items.len() == 1 {
@@ -1173,7 +1189,7 @@ fn rewrite_tuple_lit(context: &RewriteContext,
                              |item| item.span.lo,
                              |item| item.span.hi,
                              |item| {
-                                 let inner_width = context.config.max_width - indent - 1;
+                                 let inner_width = context.config.max_width - indent.width() - 1;
                                  item.rewrite(context, inner_width, indent)
                                      .unwrap_or(context.snippet(item.span))
                              },
@@ -1181,7 +1197,7 @@ fn rewrite_tuple_lit(context: &RewriteContext,
                              span.hi - BytePos(1));
 
     let budget = try_opt!(width.checked_sub(2));
-    let fmt = ListFormatting::for_fn(budget, indent);
+    let fmt = ListFormatting::for_fn(budget, indent, context.config);
     let list_str = try_opt!(write_list(&items.collect::<Vec<_>>(), &fmt));
 
     Some(format!("({})", list_str))
@@ -1192,7 +1208,7 @@ fn rewrite_binary_op(context: &RewriteContext,
                      lhs: &ast::Expr,
                      rhs: &ast::Expr,
                      width: usize,
-                     offset: usize)
+                     offset: Indent)
                      -> Option<String> {
     // FIXME: format comments between operands and operator
 
@@ -1233,11 +1249,13 @@ fn rewrite_binary_op(context: &RewriteContext,
     // We have to use multiple lines.
 
     // Re-evaluate the lhs because we have more space now:
-    let budget = try_opt!(context.config.max_width.checked_sub(offset + 1 + operator_str.len()));
+    let budget = try_opt!(context.config
+                                 .max_width
+                                 .checked_sub(offset.width() + 1 + operator_str.len()));
     Some(format!("{} {}\n{}{}",
                  try_opt!(lhs.rewrite(context, budget, offset)),
                  operator_str,
-                 make_indent(offset),
+                 make_indent(offset, context.config),
                  rhs_result))
 }
 
@@ -1245,7 +1263,7 @@ fn rewrite_unary_op(context: &RewriteContext,
                     op: &ast::UnOp,
                     expr: &ast::Expr,
                     width: usize,
-                    offset: usize)
+                    offset: Indent)
                     -> Option<String> {
     // For some reason, an UnOp is not spanned like BinOp!
     let operator_str = match *op {
@@ -1265,7 +1283,7 @@ fn rewrite_assignment(context: &RewriteContext,
                       rhs: &ast::Expr,
                       op: Option<&ast::BinOp>,
                       width: usize,
-                      offset: usize)
+                      offset: Indent)
                       -> Option<String> {
     let operator_str = match op {
         Some(op) => context.snippet(op.span),
@@ -1285,7 +1303,7 @@ pub fn rewrite_assign_rhs<S: Into<String>>(context: &RewriteContext,
                                            lhs: S,
                                            ex: &ast::Expr,
                                            width: usize,
-                                           offset: usize)
+                                           offset: Indent)
                                            -> Option<String> {
     let mut result = lhs.into();
 
@@ -1301,13 +1319,14 @@ pub fn rewrite_assign_rhs<S: Into<String>>(context: &RewriteContext,
         None => {
             // Expression did not fit on the same line as the identifier. Retry
             // on the next line.
-            let new_offset = offset + context.config.tab_spaces;
-            result.push_str(&format!("\n{}", make_indent(new_offset)));
+            let new_offset = offset.block_indent(context.config.tab_spaces);
+            result.push_str(&format!("\n{}", make_indent(new_offset, context.config)));
 
             // FIXME: we probably should related max_width to width instead of config.max_width
             // where is the 1 coming from anyway?
-            let max_width = try_opt!(context.config.max_width.checked_sub(new_offset + 1));
-            let overflow_context = context.overflow_context(context.config.tab_spaces);
+            let max_width = try_opt!(context.config.max_width.checked_sub(new_offset.width() + 1));
+            let rhs_indent = Indent::new(context.config.tab_spaces, 0);
+            let overflow_context = context.overflow_context(rhs_indent);
             let rhs = ex.rewrite(&overflow_context, max_width, new_offset);
 
             result.push_str(&&try_opt!(rhs));
diff --git a/src/imports.rs b/src/imports.rs
index 1d215d022d1..f5f81015efb 100644
--- a/src/imports.rs
+++ b/src/imports.rs
@@ -8,6 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+use Indent;
 use lists::{write_list, itemize_list, ListItem, ListFormatting, SeparatorTactic, ListTactic};
 use utils::span_after;
 use rewrite::{Rewrite, RewriteContext};
@@ -20,7 +21,7 @@
 
 impl Rewrite for ast::ViewPath {
     // Returns an empty string when the ViewPath is empty (like foo::bar::{})
-    fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Option<String> {
+    fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
         match self.node {
             ast::ViewPath_::ViewPathList(_, ref path_list) if path_list.is_empty() => {
                 Some(String::new())
@@ -68,7 +69,7 @@ fn rewrite_single_use_list(path_str: String, vpi: ast::PathListItem) -> String {
 // Pretty prints a multi-item import.
 // Assumes that path_list.len() > 0.
 pub fn rewrite_use_list(width: usize,
-                        offset: usize,
+                        offset: Indent,
                         path: &ast::Path,
                         path_list: &[ast::PathListItem],
                         span: Span,
@@ -105,6 +106,7 @@ pub fn rewrite_use_list(width: usize,
         // (loose 1 column (";"))
         v_width: remaining_width,
         ends_with_newline: false,
+        config: context.config,
     };
 
     let mut items = {
diff --git a/src/items.rs b/src/items.rs
index a14310e94ef..ae55fdf4c29 100644
--- a/src/items.rs
+++ b/src/items.rs
@@ -10,6 +10,7 @@
 
 // Formatting top-level items - functions, structs, enums, traits, impls.
 
+use Indent;
 use utils::{format_mutability, format_visibility, make_indent, contains_skip, span_after,
             end_typaram, wrap_str};
 use lists::{write_list, itemize_list, ListItem, ListFormatting, SeparatorTactic, ListTactic};
@@ -26,7 +27,7 @@
 
 impl<'a> FmtVisitor<'a> {
     pub fn visit_let(&mut self, local: &ast::Local, span: Span) {
-        self.format_missing_with_indent(span.lo);
+        self.format_missing_with_indent(span.lo, self.config);
 
         // String that is placed within the assignment pattern and expression.
         let infix = {
@@ -34,8 +35,7 @@ pub fn visit_let(&mut self, local: &ast::Local, span: Span) {
 
             if let Some(ref ty) = local.ty {
                 infix.push_str(": ");
-                // FIXME: silly width, indent
-                infix.push_str(&ty.rewrite(&self.get_context(), 1000, 0).unwrap());
+                infix.push_str(&ty.rewrite(&self.get_context(), 1000, Indent::new(0, 0)).unwrap());
             }
 
             if local.init.is_some() {
@@ -52,12 +52,13 @@ pub fn visit_let(&mut self, local: &ast::Local, span: Span) {
             let mut result = "let ".to_owned();
             let pattern_offset = self.block_indent + result.len() + infix.len();
             // 1 = ;
-            let pattern_width = match self.config.max_width.checked_sub(pattern_offset + 1) {
+            let pattern_width = self.config.max_width.checked_sub(pattern_offset.width() + 1);
+            let pattern_width = match pattern_width {
                 Some(width) => width,
                 None => return,
             };
 
-            match local.pat.rewrite(&context, pattern_offset, pattern_width) {
+            match local.pat.rewrite(&context, pattern_width, pattern_offset) {
                 Some(ref pat_string) => result.push_str(pat_string),
                 None => return,
             }
@@ -65,7 +66,8 @@ pub fn visit_let(&mut self, local: &ast::Local, span: Span) {
             result.push_str(&infix);
 
             if let Some(ref ex) = local.init {
-                let max_width = match self.config.max_width.checked_sub(context.block_indent + 1) {
+                let max_width = self.config.max_width.checked_sub(context.block_indent.width() + 1);
+                let max_width = match max_width {
                     Some(width) => width,
                     None => return,
                 };
@@ -88,7 +90,7 @@ pub fn visit_let(&mut self, local: &ast::Local, span: Span) {
     }
 
     pub fn rewrite_fn(&mut self,
-                      indent: usize,
+                      indent: Indent,
                       ident: ast::Ident,
                       fd: &ast::FnDecl,
                       explicit_self: Option<&ast::ExplicitSelf>,
@@ -124,7 +126,7 @@ pub fn rewrite_fn(&mut self,
         // this.
         if newline_brace {
             result.push('\n');
-            result.push_str(&make_indent(indent));
+            result.push_str(&make_indent(indent, self.config));
         } else {
             result.push(' ');
         }
@@ -133,7 +135,7 @@ pub fn rewrite_fn(&mut self,
     }
 
     pub fn rewrite_required_fn(&mut self,
-                               indent: usize,
+                               indent: Indent,
                                ident: ast::Ident,
                                sig: &ast::MethodSig,
                                span: Span)
@@ -160,7 +162,7 @@ pub fn rewrite_required_fn(&mut self,
     }
 
     fn rewrite_fn_base(&mut self,
-                       indent: usize,
+                       indent: Indent,
                        ident: ast::Ident,
                        fd: &ast::FnDecl,
                        explicit_self: Option<&ast::ExplicitSelf>,
@@ -207,13 +209,15 @@ fn rewrite_fn_base(&mut self,
         result.push_str(&generics_str);
 
         let context = self.get_context();
-        let ret_str = fd.output.rewrite(&context, self.config.max_width - indent, indent).unwrap();
+        let ret_str = fd.output
+                        .rewrite(&context, self.config.max_width - indent.width(), indent)
+                        .unwrap();
 
         // Args.
         let (one_line_budget, multi_line_budget, mut arg_indent) =
             self.compute_budgets_for_args(&result, indent, ret_str.len(), newline_brace);
 
-        debug!("rewrite_fn: one_line_budget: {}, multi_line_budget: {}, arg_indent: {}",
+        debug!("rewrite_fn: one_line_budget: {}, multi_line_budget: {}, arg_indent: {:?}",
                one_line_budget,
                multi_line_budget,
                arg_indent);
@@ -222,17 +226,17 @@ fn rewrite_fn_base(&mut self,
         if one_line_budget <= 0 {
             if self.config.fn_args_paren_newline {
                 result.push('\n');
-                result.push_str(&make_indent(arg_indent));
+                result.push_str(&make_indent(arg_indent, self.config));
                 arg_indent = arg_indent + 1; // extra space for `(`
                 result.push('(');
             } else {
                 result.push_str("(\n");
-                result.push_str(&make_indent(arg_indent));
+                result.push_str(&make_indent(arg_indent, self.config));
             }
         } else if self.config.fn_args_layout == StructLitStyle::Block {
-            arg_indent = indent + self.config.tab_spaces;
+            arg_indent = indent.block_indent(self.config.tab_spaces);
             result.push_str("(\n");
-            result.push_str(&make_indent(arg_indent));
+            result.push_str(&make_indent(arg_indent, self.config));
         } else {
             result.push('(');
         }
@@ -266,7 +270,7 @@ fn rewrite_fn_base(&mut self,
             // Unless we are formatting args like a block, in which case there
             // should always be room for the return type.
             if (result.contains("\n") ||
-                result.len() + indent + ret_str.len() > self.config.max_width) &&
+                result.len() + indent.width() + ret_str.len() > self.config.max_width) &&
                self.config.fn_args_layout != StructLitStyle::Block {
                 let indent = match self.config.fn_return_indent {
                     ReturnIndent::WithWhereClause => indent + 4,
@@ -277,7 +281,7 @@ fn rewrite_fn_base(&mut self,
                 };
 
                 result.push('\n');
-                result.push_str(&make_indent(indent));
+                result.push_str(&make_indent(indent, self.config));
             } else {
                 result.push(' ');
             }
@@ -326,8 +330,8 @@ fn rewrite_args(&self,
                     explicit_self: Option<&ast::ExplicitSelf>,
                     one_line_budget: usize,
                     multi_line_budget: usize,
-                    indent: usize,
-                    arg_indent: usize,
+                    indent: Indent,
+                    arg_indent: Indent,
                     span: Span)
                     -> Option<String> {
         let context = self.get_context();
@@ -386,7 +390,7 @@ fn rewrite_args(&self,
 
         let indent = match self.config.fn_arg_indent {
             BlockIndentStyle::Inherit => indent,
-            BlockIndentStyle::Tabbed => indent + self.config.tab_spaces,
+            BlockIndentStyle::Tabbed => indent.block_indent(self.config.tab_spaces),
             BlockIndentStyle::Visual => arg_indent,
         };
 
@@ -398,6 +402,7 @@ fn rewrite_args(&self,
             h_width: one_line_budget,
             v_width: multi_line_budget,
             ends_with_newline: false,
+            config: self.config,
         };
 
         write_list(&arg_items, &fmt)
@@ -405,16 +410,16 @@ fn rewrite_args(&self,
 
     fn compute_budgets_for_args(&self,
                                 result: &str,
-                                indent: usize,
+                                indent: Indent,
                                 ret_str_len: usize,
                                 newline_brace: bool)
-                                -> (usize, usize, usize) {
+                                -> (usize, usize, Indent) {
         let mut budgets = None;
 
         // Try keeping everything on the same line
         if !result.contains("\n") {
             // 3 = `() `, space is before ret_string
-            let mut used_space = indent + result.len() + ret_str_len + 3;
+            let mut used_space = indent.width() + result.len() + ret_str_len + 3;
             if !newline_brace {
                 used_space += 2;
             }
@@ -425,7 +430,7 @@ fn compute_budgets_for_args(&self,
             };
 
             // 2 = `()`
-            let used_space = indent + result.len() + 2;
+            let used_space = indent.width() + result.len() + 2;
             let max_space = self.config.ideal_width + self.config.leeway;
             debug!("compute_budgets_for_args: used_space: {}, max_space: {}",
                    used_space,
@@ -439,8 +444,8 @@ fn compute_budgets_for_args(&self,
 
         // Didn't work. we must force vertical layout and put args on a newline.
         if let None = budgets {
-            let new_indent = indent + self.config.tab_spaces;
-            let used_space = new_indent + 2; // account for `(` and `)`
+            let new_indent = indent.block_indent(self.config.tab_spaces);
+            let used_space = new_indent.width() + 2; // account for `(` and `)`
             let max_space = self.config.ideal_width + self.config.leeway;
             if used_space > max_space {
                 // Whoops! bankrupt.
@@ -475,13 +480,14 @@ pub fn visit_enum(&mut self,
         let generics_str = self.format_generics(generics,
                                                 " {",
                                                 self.block_indent,
-                                                self.block_indent + self.config.tab_spaces,
+                                                self.block_indent
+                                                    .block_indent(self.config.tab_spaces),
                                                 codemap::mk_sp(span.lo, body_start))
                                .unwrap();
         self.buffer.push_str(&generics_str);
 
         self.last_pos = body_start;
-        self.block_indent += self.config.tab_spaces;
+        self.block_indent = self.block_indent.block_indent(self.config.tab_spaces);
         for (i, f) in enum_def.variants.iter().enumerate() {
             let next_span_start: BytePos = if i == enum_def.variants.len() - 1 {
                 span.hi
@@ -491,9 +497,10 @@ pub fn visit_enum(&mut self,
 
             self.visit_variant(f, i == enum_def.variants.len() - 1, next_span_start);
         }
-        self.block_indent -= self.config.tab_spaces;
+        self.block_indent = self.block_indent.block_unindent(self.config.tab_spaces);
 
-        self.format_missing_with_indent(span.lo + BytePos(enum_snippet.rfind('}').unwrap() as u32));
+        self.format_missing_with_indent(span.lo + BytePos(enum_snippet.rfind('}').unwrap() as u32),
+                                        self.config);
         self.buffer.push_str("}");
     }
 
@@ -503,7 +510,7 @@ fn visit_variant(&mut self, field: &ast::Variant, last_field: bool, next_span_st
             return;
         }
 
-        self.format_missing_with_indent(field.span.lo);
+        self.format_missing_with_indent(field.span.lo, self.config);
 
         let result = match field.node.kind {
             ast::VariantKind::TupleVariantKind(ref types) => {
@@ -521,7 +528,9 @@ fn visit_variant(&mut self, field: &ast::Variant, last_field: bool, next_span_st
                                              |arg| {
                                                  // FIXME silly width, indent
                                                  arg.ty
-                                                    .rewrite(&self.get_context(), 1000, 0)
+                                                    .rewrite(&self.get_context(),
+                                                             1000,
+                                                             Indent::new(0, 0))
                                                     .unwrap()
                                              },
                                              span_after(field.span, "(", self.codemap),
@@ -536,7 +545,7 @@ fn visit_variant(&mut self, field: &ast::Variant, last_field: bool, next_span_st
                     } else {
                         0
                     };
-                    let budget = self.config.ideal_width - indent - comma_cost - 1; // 1 = )
+                    let budget = self.config.ideal_width - indent.width() - comma_cost - 1; // 1 = )
 
                     let fmt = ListFormatting {
                         tactic: ListTactic::HorizontalVertical,
@@ -546,6 +555,7 @@ fn visit_variant(&mut self, field: &ast::Variant, last_field: bool, next_span_st
                         h_width: budget,
                         v_width: budget,
                         ends_with_newline: true,
+                        config: self.config,
                     };
                     let list_str = match write_list(&items.collect::<Vec<_>>(), &fmt) {
                         Some(list_str) => list_str,
@@ -601,7 +611,7 @@ fn format_struct(&self,
                      struct_def: &ast::StructDef,
                      generics: Option<&ast::Generics>,
                      span: Span,
-                     offset: usize)
+                     offset: Indent)
                      -> Option<String> {
         let mut result = String::with_capacity(1024);
 
@@ -654,7 +664,7 @@ fn format_struct(&self,
                                  span.hi);
 
         // 2 terminators and a semicolon
-        let used_budget = offset + header_str.len() + generics_str.len() + 3;
+        let used_budget = offset.width() + header_str.len() + generics_str.len() + 3;
 
         // Conservative approximation
         let single_line_cost = (span.hi - struct_def.fields[0].span.lo).0;
@@ -662,7 +672,7 @@ fn format_struct(&self,
                          single_line_cost as usize + used_budget > self.config.max_width;
 
         let tactic = if break_line {
-            let indentation = make_indent(offset + self.config.tab_spaces);
+            let indentation = make_indent(offset.block_indent(self.config.tab_spaces), self.config);
             result.push('\n');
             result.push_str(&indentation);
 
@@ -672,15 +682,16 @@ fn format_struct(&self,
         };
 
         // 1 = ,
-        let budget = self.config.ideal_width - offset + self.config.tab_spaces - 1;
+        let budget = self.config.ideal_width - offset.width() + self.config.tab_spaces - 1;
         let fmt = ListFormatting {
             tactic: tactic,
             separator: ",",
             trailing_separator: self.config.struct_trailing_comma,
-            indent: offset + self.config.tab_spaces,
+            indent: offset.block_indent(self.config.tab_spaces),
             h_width: self.config.max_width,
             v_width: budget,
             ends_with_newline: true,
+            config: self.config,
         };
         let list_str = write_list(&items.collect::<Vec<_>>(), &fmt).unwrap();
 
@@ -688,7 +699,7 @@ fn format_struct(&self,
 
         if break_line {
             result.push('\n');
-            result.push_str(&make_indent(offset));
+            result.push_str(&make_indent(offset, self.config));
         }
 
         result.push_str(terminator);
@@ -727,8 +738,8 @@ fn format_header(&self, item_name: &str, ident: ast::Ident, vis: ast::Visibility
     fn format_generics(&self,
                        generics: &ast::Generics,
                        opener: &str,
-                       offset: usize,
-                       generics_offset: usize,
+                       offset: Indent,
+                       generics_offset: Indent,
                        span: Span)
                        -> Option<String> {
         let mut result = try_opt!(self.rewrite_generics(generics, offset, generics_offset, span));
@@ -740,7 +751,7 @@ fn format_generics(&self,
                                                                       Density::Tall,
                                                                       span.hi));
             result.push_str(&where_clause_str);
-            result.push_str(&make_indent(self.block_indent));
+            result.push_str(&make_indent(self.block_indent, self.config));
             result.push('\n');
             result.push_str(opener.trim());
         } else {
@@ -765,18 +776,18 @@ fn format_field(&self, field: &ast::StructField) -> String {
             ast::StructFieldKind::UnnamedField(vis) => format_visibility(vis),
         };
         // FIXME silly width, indent
-        let typ = field.node.ty.rewrite(&self.get_context(), 1000, 0).unwrap();
+        let typ = field.node.ty.rewrite(&self.get_context(), 1000, Indent::new(0, 0)).unwrap();
 
         let indent = self.block_indent + self.config.tab_spaces;
         let mut attr_str = field.node
                                 .attrs
                                 .rewrite(&self.get_context(),
-                                         self.config.max_width - indent,
+                                         self.config.max_width - indent.width(),
                                          indent)
                                 .unwrap();
         if !attr_str.is_empty() {
             attr_str.push('\n');
-            attr_str.push_str(&make_indent(indent));
+            attr_str.push_str(&make_indent(indent, self.config));
         }
 
         match name {
@@ -787,8 +798,8 @@ fn format_field(&self, field: &ast::StructField) -> String {
 
     fn rewrite_generics(&self,
                         generics: &ast::Generics,
-                        offset: usize,
-                        generics_offset: usize,
+                        offset: Indent,
+                        generics_offset: Indent,
                         span: Span)
                         -> Option<String> {
         // FIXME: convert bounds to where clauses where they get too big or if
@@ -801,12 +812,12 @@ fn rewrite_generics(&self,
 
         let offset = match self.config.generics_indent {
             BlockIndentStyle::Inherit => offset,
-            BlockIndentStyle::Tabbed => offset + self.config.tab_spaces,
+            BlockIndentStyle::Tabbed => offset.block_indent(self.config.tab_spaces),
             // 1 = <
             BlockIndentStyle::Visual => generics_offset + 1,
         };
 
-        let h_budget = self.config.max_width - generics_offset - 2;
+        let h_budget = self.config.max_width - generics_offset.width() - 2;
         // TODO: might need to insert a newline if the generics are really long.
 
         // Strings for the generics.
@@ -841,7 +852,7 @@ fn rewrite_generics(&self,
             item.item = ty;
         }
 
-        let fmt = ListFormatting::for_fn(h_budget, offset);
+        let fmt = ListFormatting::for_fn(h_budget, offset, self.config);
         let list_str = try_opt!(write_list(&items, &fmt));
 
         Some(format!("<{}>", list_str))
@@ -850,7 +861,7 @@ fn rewrite_generics(&self,
     fn rewrite_where_clause(&self,
                             where_clause: &ast::WhereClause,
                             config: &Config,
-                            indent: usize,
+                            indent: Indent,
                             density: Density,
                             span_end: BytePos)
                             -> Option<String> {
@@ -859,22 +870,23 @@ fn rewrite_where_clause(&self,
         }
 
         let extra_indent = match self.config.where_indent {
-            BlockIndentStyle::Inherit => 0,
-            BlockIndentStyle::Tabbed | BlockIndentStyle::Visual => config.tab_spaces,
+            BlockIndentStyle::Inherit => Indent::new(0, 0),
+            BlockIndentStyle::Tabbed | BlockIndentStyle::Visual => Indent::new(config.tab_spaces,
+                                                                               0),
         };
 
         let context = self.get_context();
 
         let offset = match self.config.where_pred_indent {
             BlockIndentStyle::Inherit => indent + extra_indent,
-            BlockIndentStyle::Tabbed => indent + extra_indent + config.tab_spaces,
+            BlockIndentStyle::Tabbed => indent + extra_indent.block_indent(config.tab_spaces),
             // 6 = "where ".len()
             BlockIndentStyle::Visual => indent + extra_indent + 6,
         };
         // FIXME: if where_pred_indent != Visual, then the budgets below might
         // be out by a char or two.
 
-        let budget = self.config.ideal_width + self.config.leeway - offset;
+        let budget = self.config.ideal_width + self.config.leeway - offset.width();
         let span_start = span_for_where_pred(&where_clause.predicates[0]).lo;
         let items = itemize_list(self.codemap,
                                  where_clause.predicates.iter(),
@@ -896,13 +908,16 @@ fn rewrite_where_clause(&self,
             h_width: budget,
             v_width: budget,
             ends_with_newline: true,
+            config: self.config,
         };
         let preds_str = try_opt!(write_list(&items.collect::<Vec<_>>(), &fmt));
 
         // 9 = " where ".len() + " {".len()
         if density == Density::Tall || preds_str.contains('\n') ||
-           indent + 9 + preds_str.len() > self.config.max_width {
-            Some(format!("\n{}where {}", make_indent(indent + extra_indent), preds_str))
+           indent.width() + 9 + preds_str.len() > self.config.max_width {
+            Some(format!("\n{}where {}",
+                         make_indent(indent + extra_indent, self.config),
+                         preds_str))
         } else {
             Some(format!(" where {}", preds_str))
         }
@@ -910,7 +925,7 @@ fn rewrite_where_clause(&self,
 }
 
 impl Rewrite for ast::FunctionRetTy {
-    fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Option<String> {
+    fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
         match *self {
             ast::FunctionRetTy::DefaultReturn(_) => Some(String::new()),
             ast::FunctionRetTy::NoReturn(_) => {
@@ -929,7 +944,7 @@ fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Opti
 }
 
 impl Rewrite for ast::Arg {
-    fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Option<String> {
+    fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
         if is_named_arg(self) {
             if let ast::Ty_::TyInfer = self.ty.node {
                 wrap_str(pprust::pat_to_string(&self.pat), context.config.max_width, width, offset)
diff --git a/src/lib.rs b/src/lib.rs
index 7b6adeba2c8..2ca206665e2 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -44,6 +44,7 @@
 use syntax::codemap::CodeMap;
 use syntax::diagnostics;
 
+use std::ops::{Add, Sub};
 use std::path::PathBuf;
 use std::collections::HashMap;
 use std::fmt;
@@ -80,6 +81,79 @@
 // When we get scoped annotations, we should have rustfmt::skip.
 const SKIP_ANNOTATION: &'static str = "rustfmt_skip";
 
+#[derive(Copy, Clone, Debug)]
+pub struct Indent {
+    block_indent: usize,
+    alignment: usize,
+}
+
+impl Indent {
+    pub fn new(block_indent: usize, alignment: usize) -> Indent {
+        Indent { block_indent: block_indent, alignment: alignment }
+    }
+
+    pub fn block_indent(mut self, block_indent: usize) -> Indent {
+        self.block_indent += block_indent;
+        self
+    }
+
+    pub fn block_unindent(mut self, block_indent: usize) -> Indent {
+        self.block_indent -= block_indent;
+        self
+    }
+
+    pub fn width(&self) -> usize {
+        self.block_indent + self.alignment
+    }
+
+    pub fn to_string(&self, config: &Config) -> String {
+        let (num_tabs, num_spaces) = if config.hard_tabs {
+            (self.block_indent / config.tab_spaces, self.alignment)
+        } else {
+            (0, self.block_indent + self.alignment)
+        };
+        let num_chars = num_tabs + num_spaces;
+        let mut indent = String::with_capacity(num_chars);
+        for _ in 0..num_tabs {
+            indent.push('\t')
+        }
+        for _ in 0..num_spaces {
+            indent.push(' ')
+        }
+        indent
+    }
+}
+
+impl Add for Indent {
+    type Output = Indent;
+
+    fn add(self, rhs: Indent) -> Indent {
+        Indent {
+            block_indent: self.block_indent + rhs.block_indent,
+            alignment: self.alignment + rhs.alignment,
+        }
+    }
+}
+
+impl Sub for Indent {
+    type Output = Indent;
+
+    fn sub(self, rhs: Indent) -> Indent {
+        Indent {
+            block_indent: self.block_indent - rhs.block_indent,
+            alignment: self.alignment - rhs.alignment,
+        }
+    }
+}
+
+impl Add<usize> for Indent {
+    type Output = Indent;
+
+    fn add(self, rhs: usize) -> Indent {
+        Indent { block_indent: self.block_indent, alignment: self.alignment + rhs }
+    }
+}
+
 #[derive(Copy, Clone)]
 pub enum WriteMode {
     // Backups the original file and overwrites the orignal.
diff --git a/src/lists.rs b/src/lists.rs
index 2b85c994581..40da7af198e 100644
--- a/src/lists.rs
+++ b/src/lists.rs
@@ -13,8 +13,10 @@
 
 use syntax::codemap::{self, CodeMap, BytePos};
 
+use Indent;
 use utils::{round_up_to_power_of_two, make_indent, wrap_str};
 use comment::{FindUncommented, rewrite_comment, find_comment_end};
+use config::Config;
 
 #[derive(Eq, PartialEq, Debug, Copy, Clone)]
 pub enum ListTactic {
@@ -44,7 +46,7 @@ pub struct ListFormatting<'a> {
     pub tactic: ListTactic,
     pub separator: &'a str,
     pub trailing_separator: SeparatorTactic,
-    pub indent: usize,
+    pub indent: Indent,
     // Available width if we layout horizontally.
     pub h_width: usize,
     // Available width if we layout vertically
@@ -52,10 +54,11 @@ pub struct ListFormatting<'a> {
     // Non-expressions, e.g. items, will have a new line at the end of the list.
     // Important for comment styles.
     pub ends_with_newline: bool,
+    pub config: &'a Config,
 }
 
 impl<'a> ListFormatting<'a> {
-    pub fn for_fn(width: usize, offset: usize) -> ListFormatting<'a> {
+    pub fn for_fn(width: usize, offset: Indent, config: &'a Config) -> ListFormatting<'a> {
         ListFormatting {
             tactic: ListTactic::HorizontalVertical,
             separator: ",",
@@ -64,6 +67,7 @@ pub fn for_fn(width: usize, offset: usize) -> ListFormatting<'a> {
             h_width: width,
             v_width: width,
             ends_with_newline: false,
+            config: config,
         }
     }
 }
@@ -146,12 +150,12 @@ pub fn write_list<'b>(items: &[ListItem], formatting: &ListFormatting<'b>) -> Op
     let alloc_width = if tactic == ListTactic::Horizontal {
         total_width + total_sep_len
     } else {
-        total_width + items.len() * (formatting.indent + 1)
+        total_width + items.len() * (formatting.indent.width() + 1)
     };
     let mut result = String::with_capacity(round_up_to_power_of_two(alloc_width));
 
     let mut line_len = 0;
-    let indent_str = &make_indent(formatting.indent);
+    let indent_str = &make_indent(formatting.indent, formatting.config);
     for (i, item) in items.iter().enumerate() {
         let first = i == 0;
         let last = i == items.len() - 1;
@@ -196,7 +200,8 @@ pub fn write_list<'b>(items: &[ListItem], formatting: &ListFormatting<'b>) -> Op
             let block_mode = tactic != ListTactic::Vertical;
             // Width restriction is only relevant in vertical mode.
             let max_width = formatting.v_width;
-            result.push_str(&rewrite_comment(comment, block_mode, max_width, formatting.indent));
+            result.push_str(&rewrite_comment(comment, block_mode, max_width, formatting.indent,
+                                             formatting.config));
 
             if tactic == ListTactic::Vertical {
                 result.push('\n');
@@ -206,14 +211,18 @@ pub fn write_list<'b>(items: &[ListItem], formatting: &ListFormatting<'b>) -> Op
             }
         }
 
-        let max_width = formatting.indent + formatting.v_width;
+        let max_width = formatting.indent.width() + formatting.v_width;
         let item_str = wrap_str(&item.item[..], max_width, formatting.v_width, formatting.indent);
         result.push_str(&&try_opt!(item_str));
 
         // Post-comments
         if tactic != ListTactic::Vertical && item.post_comment.is_some() {
             let comment = item.post_comment.as_ref().unwrap();
-            let formatted_comment = rewrite_comment(comment, true, formatting.v_width, 0);
+            let formatted_comment = rewrite_comment(comment,
+                                                    true,
+                                                    formatting.v_width,
+                                                    Indent::new(0, 0),
+                                                    formatting.config);
 
             result.push(' ');
             result.push_str(&formatted_comment);
@@ -226,14 +235,19 @@ pub fn write_list<'b>(items: &[ListItem], formatting: &ListFormatting<'b>) -> Op
         if tactic == ListTactic::Vertical && item.post_comment.is_some() {
             // 1 = space between item and comment.
             let width = formatting.v_width.checked_sub(item_width + 1).unwrap_or(1);
-            let offset = formatting.indent + item_width + 1;
+            let mut offset = formatting.indent;
+            offset.alignment += item_width + 1;
             let comment = item.post_comment.as_ref().unwrap();
             // Use block-style only for the last item or multiline comments.
             let block_style = !formatting.ends_with_newline && last ||
                               comment.trim().contains('\n') ||
                               comment.trim().len() > width;
 
-            let formatted_comment = rewrite_comment(comment, block_style, width, offset);
+            let formatted_comment = rewrite_comment(comment,
+                                                    block_style,
+                                                    width,
+                                                    offset,
+                                                    formatting.config);
 
             result.push(' ');
             result.push_str(&formatted_comment);
diff --git a/src/macros.rs b/src/macros.rs
index dd742ad46c8..8c38326ee8a 100644
--- a/src/macros.rs
+++ b/src/macros.rs
@@ -25,6 +25,7 @@
 use syntax::parse::token::{Eof, Comma, Token};
 use syntax::parse::{ParseSess, tts_to_parser};
 
+use Indent;
 use rewrite::RewriteContext;
 use expr::{rewrite_call, rewrite_array};
 use comment::FindUncommented;
@@ -46,7 +47,7 @@ enum MacroStyle {
 pub fn rewrite_macro(mac: &ast::Mac,
                      context: &RewriteContext,
                      width: usize,
-                     offset: usize)
+                     offset: Indent)
                      -> Option<String> {
     let ast::Mac_::MacInvocTT(ref path, ref tt_vec, _) = mac.node;
     let style = macro_style(mac, context);
diff --git a/src/missed_spans.rs b/src/missed_spans.rs
index 535fc4c8ad9..c8da3e76b63 100644
--- a/src/missed_spans.rs
+++ b/src/missed_spans.rs
@@ -8,6 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+use config::Config;
 use utils::make_indent;
 use visitor::FmtVisitor;
 
@@ -20,15 +21,15 @@ pub fn format_missing(&mut self, end: BytePos) {
         self.format_missing_inner(end, |this, last_snippet, _| this.buffer.push_str(last_snippet))
     }
 
-    pub fn format_missing_with_indent(&mut self, end: BytePos) {
+    pub fn format_missing_with_indent(&mut self, end: BytePos, config: &Config) {
         self.format_missing_inner(end,
                                   |this, last_snippet, snippet| {
                                       this.buffer.push_str(last_snippet.trim_right());
                                       if last_snippet == snippet {
-                // No new lines in the snippet.
+                                          // No new lines in the snippet.
                                           this.buffer.push_str("\n");
                                       }
-                                      let indent = make_indent(this.block_indent);
+                                      let indent = make_indent(this.block_indent, config);
                                       this.buffer.push_str(&indent);
                                   })
     }
diff --git a/src/rewrite.rs b/src/rewrite.rs
index 49c09ac53d1..2e0f5691d2e 100644
--- a/src/rewrite.rs
+++ b/src/rewrite.rs
@@ -12,6 +12,7 @@
 
 use syntax::codemap::{CodeMap, Span};
 
+use Indent;
 use config::Config;
 
 pub trait Rewrite {
@@ -22,7 +23,7 @@ pub trait Rewrite {
     /// `width` is the maximum number of characters on the last line
     /// (excluding offset). The width of other lines is not limited by
     /// `width`.
-    fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Option<String>;
+    fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String>;
 }
 
 pub struct RewriteContext<'a> {
@@ -30,12 +31,12 @@ pub struct RewriteContext<'a> {
     pub config: &'a Config,
 
     // Indentation due to nesting of blocks.
-    pub block_indent: usize,
+    pub block_indent: Indent,
     // *Extra* indentation due to overflowing to the next line, e.g.,
     // let foo =
     //     bar();
     // The extra 4 spaces when formatting `bar()` is overflow_indent.
-    pub overflow_indent: usize,
+    pub overflow_indent: Indent,
 }
 
 impl<'a> RewriteContext<'a> {
@@ -43,12 +44,12 @@ pub fn nested_context(&self) -> RewriteContext<'a> {
         RewriteContext {
             codemap: self.codemap,
             config: self.config,
-            block_indent: self.block_indent + self.config.tab_spaces,
+            block_indent: self.block_indent.block_indent(self.config.tab_spaces),
             overflow_indent: self.overflow_indent,
         }
     }
 
-    pub fn overflow_context(&self, overflow: usize) -> RewriteContext<'a> {
+    pub fn overflow_context(&self, overflow: Indent) -> RewriteContext<'a> {
         RewriteContext {
             codemap: self.codemap,
             config: self.config,
diff --git a/src/string.rs b/src/string.rs
index 5e5af61faf5..3da0a5f4a25 100644
--- a/src/string.rs
+++ b/src/string.rs
@@ -13,6 +13,8 @@
 use unicode_segmentation::UnicodeSegmentation;
 use regex::Regex;
 
+use Indent;
+use config::Config;
 use utils::{make_indent, round_up_to_power_of_two};
 
 use MIN_STRING;
@@ -23,8 +25,9 @@ pub struct StringFormat<'a> {
     pub line_start: &'a str,
     pub line_end: &'a str,
     pub width: usize,
-    pub offset: usize,
+    pub offset: Indent,
     pub trim_end: bool,
+    pub config: &'a Config,
 }
 
 // TODO: simplify this!
@@ -36,7 +39,7 @@ pub fn rewrite_string<'a>(s: &str, fmt: &StringFormat<'a>) -> String {
 
     let graphemes = UnicodeSegmentation::graphemes(&*stripped_str, false).collect::<Vec<&str>>();
 
-    let indent = make_indent(fmt.offset);
+    let indent = make_indent(fmt.offset, fmt.config);
     let indent = &indent;
 
     let mut cur_start = 0;
diff --git a/src/types.rs b/src/types.rs
index e52909b0d5c..9ba50a59cd9 100644
--- a/src/types.rs
+++ b/src/types.rs
@@ -12,12 +12,13 @@
 use syntax::print::pprust;
 use syntax::codemap::{self, Span, BytePos, CodeMap};
 
+use Indent;
 use lists::{itemize_list, write_list, ListFormatting};
 use rewrite::{Rewrite, RewriteContext};
 use utils::{extra_offset, span_after};
 
 impl Rewrite for ast::Path {
-    fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Option<String> {
+    fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
         rewrite_path(context, None, self, width, offset)
     }
 }
@@ -27,7 +28,7 @@ pub fn rewrite_path(context: &RewriteContext,
                     qself: Option<&ast::QSelf>,
                     path: &ast::Path,
                     width: usize,
-                    offset: usize)
+                    offset: Indent)
                     -> Option<String> {
     let skip_count = qself.map(|x| x.position).unwrap_or(0);
 
@@ -80,7 +81,7 @@ fn rewrite_path_segments<'a, I>(mut buffer: String,
                                 span_hi: BytePos,
                                 context: &RewriteContext,
                                 width: usize,
-                                offset: usize)
+                                offset: Indent)
                                 -> Option<String>
     where I: Iterator<Item = &'a ast::PathSegment>
 {
@@ -128,7 +129,7 @@ fn get_span(&self) -> Span {
 
 impl<'a> Rewrite for SegmentParam<'a> {
     // FIXME: doesn't always use width, offset.
-    fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Option<String> {
+    fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
         Some(match *self {
             SegmentParam::LifeTime(ref lt) => {
                 pprust::lifetime_to_string(lt)
@@ -186,7 +187,7 @@ fn rewrite_segment(segment: &ast::PathSegment,
                    span_hi: BytePos,
                    context: &RewriteContext,
                    width: usize,
-                   offset: usize)
+                   offset: Indent)
                    -> Option<String> {
     let ident_len = segment.identifier.to_string().len();
     let width = try_opt!(width.checked_sub(ident_len));
@@ -229,7 +230,7 @@ fn rewrite_segment(segment: &ast::PathSegment,
                                      list_lo,
                                      span_hi);
 
-            let fmt = ListFormatting::for_fn(list_width, offset + extra_offset);
+            let fmt = ListFormatting::for_fn(list_width, offset + extra_offset, context.config);
             let list_str = try_opt!(write_list(&items.collect::<Vec<_>>(), &fmt));
 
             // Update position of last bracket.
@@ -257,7 +258,7 @@ fn rewrite_segment(segment: &ast::PathSegment,
             let budget = try_opt!(width.checked_sub(output.len() + 2));
 
             // 1 for (
-            let fmt = ListFormatting::for_fn(budget, offset + 1);
+            let fmt = ListFormatting::for_fn(budget, offset + 1, context.config);
             let list_str = try_opt!(write_list(&items.collect::<Vec<_>>(), &fmt));
 
             format!("({}){}", list_str, output)
@@ -269,7 +270,7 @@ fn rewrite_segment(segment: &ast::PathSegment,
 }
 
 impl Rewrite for ast::WherePredicate {
-    fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Option<String> {
+    fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
         // TODO: dead spans?
         // TODO: don't assume we'll always fit on one line...
         Some(match *self {
@@ -340,7 +341,7 @@ fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Opti
 }
 
 impl Rewrite for ast::LifetimeDef {
-    fn rewrite(&self, _: &RewriteContext, _: usize, _: usize) -> Option<String> {
+    fn rewrite(&self, _: &RewriteContext, _: usize, _: Indent) -> Option<String> {
         if self.bounds.is_empty() {
             Some(pprust::lifetime_to_string(&self.lifetime))
         } else {
@@ -356,7 +357,7 @@ fn rewrite(&self, _: &RewriteContext, _: usize, _: usize) -> Option<String> {
 }
 
 impl Rewrite for ast::TyParamBound {
-    fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Option<String> {
+    fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
         match *self {
             ast::TyParamBound::TraitTyParamBound(ref tref, ast::TraitBoundModifier::None) => {
                 tref.rewrite(context, width, offset)
@@ -372,7 +373,7 @@ fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Opti
 }
 
 impl Rewrite for ast::TyParamBounds {
-    fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Option<String> {
+    fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
         let strs: Vec<_> = self.iter()
                                .map(|b| b.rewrite(context, width, offset).unwrap())
                                .collect();
@@ -382,7 +383,7 @@ fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Opti
 
 // FIXME: this assumes everything will fit on one line
 impl Rewrite for ast::TyParam {
-    fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Option<String> {
+    fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
         let mut result = String::with_capacity(128);
         result.push_str(&self.ident.to_string());
         if !self.bounds.is_empty() {
@@ -407,7 +408,7 @@ fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Opti
 
 // FIXME: this assumes everything will fit on one line
 impl Rewrite for ast::PolyTraitRef {
-    fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Option<String> {
+    fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
         if !self.bound_lifetimes.is_empty() {
             let lifetime_str = self.bound_lifetimes
                                    .iter()
@@ -430,7 +431,7 @@ fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Opti
 
 impl Rewrite for ast::Ty {
     // FIXME doesn't always use width, offset
-    fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Option<String> {
+    fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
         match self.node {
             ast::TyPath(None, ref p) => {
                 p.rewrite(context, width, offset)
diff --git a/src/utils.rs b/src/utils.rs
index 42d1151ba38..3843e75973e 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -13,17 +13,19 @@
 use syntax::ast::{self, Visibility, Attribute, MetaItem, MetaItem_};
 use syntax::codemap::{CodeMap, Span, BytePos};
 
+use Indent;
 use comment::FindUncommented;
+use config::Config;
 use rewrite::{Rewrite, RewriteContext};
 
 use SKIP_ANNOTATION;
 
 // Computes the length of a string's last line, minus offset.
 #[inline]
-pub fn extra_offset(text: &str, offset: usize) -> usize {
+pub fn extra_offset(text: &str, offset: Indent) -> usize {
     match text.rfind('\n') {
         // 1 for newline character
-        Some(idx) => text.len() - idx - 1 - offset,
+        Some(idx) => text.len() - idx - 1 - offset.width(),
         None => text.len(),
     }
 }
@@ -36,12 +38,8 @@ pub fn span_after(original: Span, needle: &str, codemap: &CodeMap) -> BytePos {
 }
 
 #[inline]
-pub fn make_indent(width: usize) -> String {
-    let mut indent = String::with_capacity(width);
-    for _ in 0..width {
-        indent.push(' ')
-    }
-    indent
+pub fn make_indent(indent: Indent, config: &Config) -> String {
+    indent.to_string(config)
 }
 
 #[inline]
@@ -186,7 +184,7 @@ macro_rules! try_opt {
 
 // Wraps string-like values in an Option. Returns Some when the string adheres
 // to the Rewrite constraints defined for the Rewrite trait and else otherwise.
-pub fn wrap_str<S: AsRef<str>>(s: S, max_width: usize, width: usize, offset: usize) -> Option<S> {
+pub fn wrap_str<S: AsRef<str>>(s: S, max_width: usize, width: usize, offset: Indent) -> Option<S> {
     {
         let snippet = s.as_ref();
 
@@ -197,7 +195,7 @@ pub fn wrap_str<S: AsRef<str>>(s: S, max_width: usize, width: usize, offset: usi
 
             // The caller of this function has already placed `offset`
             // characters on the first line.
-            let first_line_max_len = try_opt!(max_width.checked_sub(offset));
+            let first_line_max_len = try_opt!(max_width.checked_sub(offset.width()));
             if lines.next().unwrap().len() > first_line_max_len {
                 return None;
             }
@@ -211,7 +209,7 @@ pub fn wrap_str<S: AsRef<str>>(s: S, max_width: usize, width: usize, offset: usi
             // indentation.
             // A special check for the last line, since the caller may
             // place trailing characters on this line.
-            if snippet.lines().rev().next().unwrap().len() > offset + width {
+            if snippet.lines().rev().next().unwrap().len() > offset.width() + width {
                 return None;
             }
         }
@@ -221,7 +219,7 @@ pub fn wrap_str<S: AsRef<str>>(s: S, max_width: usize, width: usize, offset: usi
 }
 
 impl Rewrite for String {
-    fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Option<String> {
+    fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
         wrap_str(self, context.config.max_width, width, offset).map(ToOwned::to_owned)
     }
 }
diff --git a/src/visitor.rs b/src/visitor.rs
index 1e3ebf71cef..d0a5df12221 100644
--- a/src/visitor.rs
+++ b/src/visitor.rs
@@ -14,6 +14,7 @@
 
 use strings::string_buffer::StringBuffer;
 
+use Indent;
 use utils;
 use config::Config;
 use rewrite::{Rewrite, RewriteContext};
@@ -25,7 +26,7 @@ pub struct FmtVisitor<'a> {
     pub buffer: StringBuffer,
     pub last_pos: BytePos,
     // TODO: RAII util for indenting
-    pub block_indent: usize,
+    pub block_indent: Indent,
     pub config: &'a Config,
 }
 
@@ -39,7 +40,11 @@ fn visit_expr(&mut self, ex: &'v ast::Expr) {
         self.format_missing(ex.span.lo);
 
         let offset = self.buffer.cur_offset();
-        let rewrite = ex.rewrite(&self.get_context(), self.config.max_width - offset, offset);
+        // FIXME: We put the entire offset into the block_indent, which might not be correct in all
+        // situations.
+        let rewrite = ex.rewrite(&self.get_context(),
+                                 self.config.max_width - offset,
+                                 Indent::new(offset, 0));
 
         if let Some(new_str) = rewrite {
             self.buffer.push_str(&new_str);
@@ -56,7 +61,7 @@ fn visit_stmt(&mut self, stmt: &'v ast::Stmt) {
                 }
             }
             ast::Stmt_::StmtExpr(ref ex, _) | ast::Stmt_::StmtSemi(ref ex, _) => {
-                self.format_missing_with_indent(stmt.span.lo);
+                self.format_missing_with_indent(stmt.span.lo, self.config);
                 let suffix = if let ast::Stmt_::StmtExpr(..) = stmt.node {
                     ""
                 } else {
@@ -65,7 +70,8 @@ fn visit_stmt(&mut self, stmt: &'v ast::Stmt) {
 
                 // 1 = trailing semicolon;
                 let rewrite = ex.rewrite(&self.get_context(),
-                                         self.config.max_width - self.block_indent - suffix.len(),
+                                         self.config.max_width - self.block_indent.width() -
+                                         suffix.len(),
                                          self.block_indent);
 
                 if let Some(new_str) = rewrite {
@@ -75,7 +81,7 @@ fn visit_stmt(&mut self, stmt: &'v ast::Stmt) {
                 }
             }
             ast::Stmt_::StmtMac(ref _mac, _macro_style) => {
-                self.format_missing_with_indent(stmt.span.lo);
+                self.format_missing_with_indent(stmt.span.lo, self.config);
                 visit::walk_stmt(self, stmt);
             }
         }
@@ -96,7 +102,7 @@ fn visit_block(&mut self, b: &'v ast::Block) {
         };
 
         self.last_pos = self.last_pos + brace_compensation;
-        self.block_indent += self.config.tab_spaces;
+        self.block_indent = self.block_indent.block_indent(self.config.tab_spaces);
         self.buffer.push_str("{");
 
         for stmt in &b.stmts {
@@ -105,15 +111,15 @@ fn visit_block(&mut self, b: &'v ast::Block) {
 
         match b.expr {
             Some(ref e) => {
-                self.format_missing_with_indent(e.span.lo);
+                self.format_missing_with_indent(e.span.lo, self.config);
                 self.visit_expr(e);
             }
             None => {}
         }
 
-        self.block_indent -= self.config.tab_spaces;
-        // TODO: we should compress any newlines here to just one.
-        self.format_missing_with_indent(b.span.hi - brace_compensation);
+        self.block_indent = self.block_indent.block_unindent(self.config.tab_spaces);
+        // TODO: we should compress any newlines here to just one
+        self.format_missing_with_indent(b.span.hi - brace_compensation, self.config);
         self.buffer.push_str("}");
         self.last_pos = b.span.hi;
     }
@@ -126,6 +132,7 @@ fn visit_fn(&mut self,
                 b: &'v ast::Block,
                 s: Span,
                 _: ast::NodeId) {
+
         let indent = self.block_indent;
         let rewrite = match fk {
             visit::FnKind::ItemFn(ident,
@@ -161,7 +168,7 @@ fn visit_fn(&mut self,
         };
 
         if let Some(fn_str) = rewrite {
-            self.format_missing_with_indent(s.lo);
+            self.format_missing_with_indent(s.lo, self.config);
             self.buffer.push_str(&fn_str);
         } else {
             self.format_missing(b.span.lo);
@@ -191,31 +198,31 @@ fn visit_item(&mut self, item: &'v ast::Item) {
             }
             ast::Item_::ItemImpl(..) |
             ast::Item_::ItemTrait(..) => {
-                self.block_indent += self.config.tab_spaces;
+                self.block_indent = self.block_indent.block_indent(self.config.tab_spaces);
                 visit::walk_item(self, item);
-                self.block_indent -= self.config.tab_spaces;
+                self.block_indent = self.block_indent.block_unindent(self.config.tab_spaces);
             }
             ast::Item_::ItemExternCrate(_) => {
-                self.format_missing_with_indent(item.span.lo);
+                self.format_missing_with_indent(item.span.lo, self.config);
                 let new_str = self.snippet(item.span);
                 self.buffer.push_str(&new_str);
                 self.last_pos = item.span.hi;
             }
             ast::Item_::ItemStruct(ref def, ref generics) => {
-                self.format_missing_with_indent(item.span.lo);
+                self.format_missing_with_indent(item.span.lo, self.config);
                 self.visit_struct(item.ident, item.vis, def, generics, item.span);
             }
             ast::Item_::ItemEnum(ref def, ref generics) => {
-                self.format_missing_with_indent(item.span.lo);
+                self.format_missing_with_indent(item.span.lo, self.config);
                 self.visit_enum(item.ident, item.vis, def, generics, item.span);
                 self.last_pos = item.span.hi;
             }
             ast::Item_::ItemMod(ref module) => {
-                self.format_missing_with_indent(item.span.lo);
+                self.format_missing_with_indent(item.span.lo, self.config);
                 self.format_mod(module, item.span, item.ident);
             }
             ast::Item_::ItemMac(..) => {
-                self.format_missing_with_indent(item.span.lo);
+                self.format_missing_with_indent(item.span.lo, self.config);
                 // TODO: we cannot format these yet, because of a bad span.
                 // See rust lang issue #28424.
                 // visit::walk_item(self, item);
@@ -232,7 +239,7 @@ fn visit_trait_item(&mut self, ti: &'v ast::TraitItem) {
         }
 
         if let ast::TraitItem_::MethodTraitItem(ref sig, None) = ti.node {
-            self.format_missing_with_indent(ti.span.lo);
+            self.format_missing_with_indent(ti.span.lo, self.config);
 
             let indent = self.block_indent;
             let new_fn = self.rewrite_required_fn(indent, ti.ident, sig, ti.span);
@@ -256,7 +263,7 @@ fn visit_impl_item(&mut self, ii: &'v ast::ImplItem) {
 
     fn visit_mac(&mut self, mac: &'v ast::Mac) {
         // 1 = ;
-        let width = self.config.max_width - self.block_indent - 1;
+        let width = self.config.max_width - self.block_indent.width() - 1;
         let rewrite = rewrite_macro(mac, &self.get_context(), width, self.block_indent);
 
         if let Some(res) = rewrite {
@@ -272,7 +279,7 @@ pub fn from_codemap<'b>(codemap: &'b CodeMap, config: &'b Config) -> FmtVisitor<
             codemap: codemap,
             buffer: StringBuffer::new(),
             last_pos: BytePos(0),
-            block_indent: 0,
+            block_indent: Indent { block_indent: 0, alignment: 0 },
             config: config,
         }
     }
@@ -296,13 +303,13 @@ pub fn visit_attrs(&mut self, attrs: &[ast::Attribute]) -> bool {
         }
 
         let first = &attrs[0];
-        self.format_missing_with_indent(first.span.lo);
+        self.format_missing_with_indent(first.span.lo, self.config);
 
         if utils::contains_skip(attrs) {
             true
         } else {
             let rewrite = attrs.rewrite(&self.get_context(),
-                                        self.config.max_width - self.block_indent,
+                                        self.config.max_width - self.block_indent.width(),
                                         self.block_indent)
                                .unwrap();
             self.buffer.push_str(&rewrite);
@@ -323,32 +330,33 @@ fn format_mod(&mut self, m: &ast::Mod, s: Span, ident: ast::Ident) {
 
         if is_internal {
             debug!("FmtVisitor::format_mod: internal mod");
-            self.block_indent += self.config.tab_spaces;
+            self.block_indent = self.block_indent.block_indent(self.config.tab_spaces);
             visit::walk_mod(self, m);
             debug!("... last_pos after: {:?}", self.last_pos);
-            self.block_indent -= self.config.tab_spaces;
+            self.block_indent = self.block_indent.block_unindent(self.config.tab_spaces);
         }
     }
 
     pub fn format_separate_mod(&mut self, m: &ast::Mod, filename: &str) {
         let filemap = self.codemap.get_filemap(filename);
         self.last_pos = filemap.start_pos;
-        self.block_indent = 0;
+        self.block_indent = Indent::new(0, 0);
         visit::walk_mod(self, m);
         self.format_missing(filemap.end_pos);
     }
 
     fn format_import(&mut self, vis: ast::Visibility, vp: &ast::ViewPath, span: Span) {
         let vis = utils::format_visibility(vis);
-        let offset = self.block_indent + vis.len() + "use ".len();
+        let mut offset = self.block_indent;
+        offset.alignment += vis.len() + "use ".len();
         let context = RewriteContext {
             codemap: self.codemap,
             config: self.config,
             block_indent: self.block_indent,
-            overflow_indent: 0,
+            overflow_indent: Indent::new(0, 0),
         };
         // 1 = ";"
-        match vp.rewrite(&context, self.config.max_width - offset - 1, offset) {
+        match vp.rewrite(&context, self.config.max_width - offset.width() - 1, offset) {
             Some(ref s) if s.is_empty() => {
                 // Format up to last newline
                 let prev_span = codemap::mk_sp(self.last_pos, span.lo);
@@ -361,12 +369,12 @@ fn format_import(&mut self, vis: ast::Visibility, vp: &ast::ViewPath, span: Span
             }
             Some(ref s) => {
                 let s = format!("{}use {};", vis, s);
-                self.format_missing_with_indent(span.lo);
+                self.format_missing_with_indent(span.lo, self.config);
                 self.buffer.push_str(&s);
                 self.last_pos = span.hi;
             }
             None => {
-                self.format_missing_with_indent(span.lo);
+                self.format_missing_with_indent(span.lo, self.config);
                 self.format_missing(span.hi);
             }
         }
@@ -377,18 +385,18 @@ pub fn get_context(&self) -> RewriteContext {
             codemap: self.codemap,
             config: self.config,
             block_indent: self.block_indent,
-            overflow_indent: 0,
+            overflow_indent: Indent::new(0, 0),
         }
     }
 }
 
 impl<'a> Rewrite for [ast::Attribute] {
-    fn rewrite(&self, context: &RewriteContext, _: usize, offset: usize) -> Option<String> {
+    fn rewrite(&self, context: &RewriteContext, _: usize, offset: Indent) -> Option<String> {
         let mut result = String::new();
         if self.is_empty() {
             return Some(result);
         }
-        let indent = utils::make_indent(offset);
+        let indent = utils::make_indent(offset, context.config);
 
         for (i, a) in self.iter().enumerate() {
             let a_str = context.snippet(a.span);
@@ -403,8 +411,9 @@ fn rewrite(&self, context: &RewriteContext, _: usize, offset: usize) -> Option<S
                 if !comment.is_empty() {
                     let comment = rewrite_comment(comment,
                                                   false,
-                                                  context.config.max_width - offset,
-                                                  offset);
+                                                  context.config.max_width - offset.width(),
+                                                  offset,
+                                                  context.config);
                     result.push_str(&indent);
                     result.push_str(&comment);
                     result.push('\n');