syntax: remove unused 'mut' variables

src/libsyntax/diagnostic.rs

@@ -342,7 +342,7 @@ fn highlight_lines_internal(cm: @codemap::CodeMap,
         while num > 0u { num /= 10u; digits += 1u; }
 
         // indent past |name:## | and the 0-offset column location
-        let mut left = str::len(fm.name) + digits + lo.col.to_uint() + 3u;
+        let left = str::len(fm.name) + digits + lo.col.to_uint() + 3u;
         let mut s = ~"";
         // Skip is the number of characters we need to skip because they are
         // part of the 'filename:line ' part of the previous line.

src/libsyntax/ext/fmt.rs

@@ -96,7 +96,7 @@ fn pieces_to_expr(cx: @ext_ctxt, sp: span,
             }
         }
         fn make_ty(cx: @ext_ctxt, sp: span, t: Ty) -> @ast::expr {
-            let mut rt_type;
+            let rt_type;
             match t {
               TyHex(c) => match c {
                 CaseUpper => rt_type = ~"TyHexUpper",
@@ -272,16 +272,18 @@ fn pieces_to_expr(cx: @ext_ctxt, sp: span,
     /* Translate each piece (portion of the fmt expression) by invoking the
        corresponding function in core::unstable::extfmt. Each function takes a
        buffer to insert data into along with the data being formatted. */
+    let npieces = pieces.len();
     do vec::consume(pieces) |i, pc| {
         match pc {
             /* Raw strings get appended via str::push_str */
             PieceString(s) => {
                 let portion = mk_uniq_str(cx, fmt_sp, s);
 
                 /* If this is the first portion, then initialize the local
-                   buffer with it directly */
+                   buffer with it directly. If it's actually the only piece,
+                   then there's no need for it to be mutable */
                 if i == 0 {
-                    stms.push(mk_local(cx, fmt_sp, true, ident, portion));
+                    stms.push(mk_local(cx, fmt_sp, npieces > 1, ident, portion));
                 } else {
                     let args = ~[mk_mut_addr_of(cx, fmt_sp, buf()), portion];
                     let call = mk_call_global(cx,

src/libsyntax/parse/attr.rs

@@ -73,7 +73,7 @@ impl parser_attr for Parser {
         self.expect(&token::LBRACKET);
         let meta_item = self.parse_meta_item();
         self.expect(&token::RBRACKET);
-        let mut hi = self.span.hi;
+        let hi = self.span.hi;
         return spanned(lo, hi, ast::attribute_ { style: style,
                                                  value: meta_item,
                                                  is_sugared_doc: false });
@@ -141,16 +141,16 @@ impl parser_attr for Parser {
             token::EQ => {
                 self.bump();
                 let lit = self.parse_lit();
-                let mut hi = self.span.hi;
+                let hi = self.span.hi;
                 @spanned(lo, hi, ast::meta_name_value(name, lit))
             }
             token::LPAREN => {
                 let inner_items = self.parse_meta_seq();
-                let mut hi = self.span.hi;
+                let hi = self.span.hi;
                 @spanned(lo, hi, ast::meta_list(name, inner_items))
             }
             _ => {
-                let mut hi = self.span.hi;
+                let hi = self.span.hi;
                 @spanned(lo, hi, ast::meta_word(name))
             }
         }

src/libsyntax/parse/comments.rs

@@ -229,7 +229,7 @@ fn read_block_comment(rdr: @mut StringReader,
     debug!(">>> block comment");
     let p = rdr.last_pos;
     let mut lines: ~[~str] = ~[];
-    let mut col: CharPos = rdr.col;
+    let col: CharPos = rdr.col;
     bump(rdr);
     bump(rdr);
 

src/libsyntax/parse/parser.rs

@@ -810,7 +810,7 @@ pub impl Parser {
     // This version of parse arg doesn't necessarily require
     // identifier names.
     fn parse_arg_general(&self, require_name: bool) -> arg {
-        let mut m;
+        let m;
         let mut is_mutbl = false;
         let pat = if require_name || self.is_named_argument() {
             m = self.parse_arg_mode();
@@ -1154,7 +1154,7 @@ pub impl Parser {
         let lo = self.span.lo;
         let mut hi = self.span.hi;
 
-        let mut ex: expr_;
+        let ex: expr_;
 
         if *self.token == token::LPAREN {
             self.bump();
@@ -1629,9 +1629,9 @@ pub impl Parser {
     // parse a prefix-operator expr
     fn parse_prefix_expr(&self) -> @expr {
         let lo = self.span.lo;
-        let mut hi;
+        let hi;
 
-        let mut ex;
+        let ex;
         match *self.token {
           token::NOT => {
             self.bump();
@@ -1781,7 +1781,7 @@ pub impl Parser {
           token::BINOPEQ(op) => {
               self.bump();
               let rhs = self.parse_expr();
-              let mut aop;
+              let aop;
               match op {
                   token::PLUS => aop = add,
                   token::MINUS => aop = subtract,
@@ -1956,7 +1956,7 @@ pub impl Parser {
         let lo = self.last_span.lo;
         let cond = self.parse_expr();
         let body = self.parse_block_no_value();
-        let mut hi = body.span.hi;
+        let hi = body.span.hi;
         return self.mk_expr(lo, hi, expr_while(cond, body));
     }
 
@@ -1984,7 +1984,7 @@ pub impl Parser {
 
             let lo = self.last_span.lo;
             let body = self.parse_block_no_value();
-            let mut hi = body.span.hi;
+            let hi = body.span.hi;
             return self.mk_expr(lo, hi, expr_loop(body, opt_ident));
         } else {
             // This is a 'continue' expression
@@ -2043,7 +2043,7 @@ pub impl Parser {
 
             arms.push(ast::arm { pats: pats, guard: guard, body: blk });
         }
-        let mut hi = self.span.hi;
+        let hi = self.span.hi;
         self.bump();
         return self.mk_expr(lo, hi, expr_match(discriminant, arms));
     }
@@ -2162,7 +2162,7 @@ pub impl Parser {
             let hi1 = self.last_span.lo;
             let fieldpath = ast_util::ident_to_path(mk_sp(lo1, hi1),
                                                     fieldname);
-            let mut subpat;
+            let subpat;
             if *self.token == token::COLON {
                 self.bump();
                 subpat = self.parse_pat(refutable);
@@ -2183,7 +2183,7 @@ pub impl Parser {
 
         let lo = self.span.lo;
         let mut hi = self.span.hi;
-        let mut pat;
+        let pat;
         match *self.token {
           token::UNDERSCORE => { self.bump(); pat = pat_wild; }
           token::AT => {
@@ -2534,7 +2534,7 @@ pub impl Parser {
             match self.parse_item_or_view_item(/*bad*/ copy item_attrs,
                                                true, false, false) {
               iovi_item(i) => {
-                let mut hi = i.span.hi;
+                let hi = i.span.hi;
                 let decl = @spanned(lo, hi, decl_item(i));
                 return @spanned(lo, hi, stmt_decl(decl, self.get_id()));
               }
@@ -2704,7 +2704,7 @@ pub impl Parser {
                 }
             }
         }
-        let mut hi = self.span.hi;
+        let hi = self.span.hi;
         self.bump();
         let bloc = ast::blk_ {
             view_items: view_items,
@@ -3590,7 +3590,7 @@ pub impl Parser {
         let purity = self.parse_fn_purity();
         let (ident, generics) = self.parse_fn_header();
         let decl = self.parse_fn_decl(|p| p.parse_arg());
-        let mut hi = self.span.hi;
+        let hi = self.span.hi;
         self.expect(&token::SEMI);
         @ast::foreign_item { ident: ident,
                              attrs: attrs,
@@ -3798,7 +3798,7 @@ pub impl Parser {
             }
         }
         self.bump();
-        let mut actual_dtor = do the_dtor.map |dtor| {
+        let actual_dtor = do the_dtor.map |dtor| {
             let (d_body, d_attrs, d_s) = copy *dtor;
             codemap::spanned { node: ast::struct_dtor_ { id: self.get_id(),
                                                      attrs: d_attrs,

src/libsyntax/print/pp.rs

@@ -146,9 +146,9 @@ pub fn mk_printer(out: @io::Writer, linewidth: uint) -> @mut Printer {
     // fall behind.
     let n: uint = 3 * linewidth;
     debug!("mk_printer %u", linewidth);
-    let mut token: ~[token] = vec::from_elem(n, EOF);
-    let mut size: ~[int] = vec::from_elem(n, 0);
-    let mut scan_stack: ~[uint] = vec::from_elem(n, 0u);
+    let token: ~[token] = vec::from_elem(n, EOF);
+    let size: ~[int] = vec::from_elem(n, 0);
+    let scan_stack: ~[uint] = vec::from_elem(n, 0u);
     @mut Printer {
         out: @out,
         buf_len: n,

src/libsyntax/print/pprust.rs

@@ -1972,7 +1972,7 @@ pub fn print_ty_fn(s: @ps,
 
 pub fn maybe_print_trailing_comment(s: @ps, span: codemap::span,
                                     next_pos: Option<BytePos>) {
-    let mut cm;
+    let cm;
     match s.cm { Some(ccm) => cm = ccm, _ => return }
     match next_comment(s) {
       Some(ref cmnt) => {