remove the `float` type

It is simply defined as `f64` across every platform right now.

A use case hasn't been presented for a `float` type defined as the
highest precision floating point type implemented in hardware on the
platform. Performance-wise, using the smallest precision correct for the
use case greatly saves on cache space and allows for fitting more
numbers into SSE/AVX registers.

If there was a use case, this could be implemented as simply a type
alias or a struct thanks to `#[cfg(...)]`.

Closes #6592

The mailing list thread, for reference:

https://mail.mozilla.org/pipermail/rust-dev/2013-July/004632.html

4 files changed, 2 insertions, 9 deletions

diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index f2d7ebdd599..5056bd5a00d 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -765,7 +765,6 @@ impl ToStr for uint_ty {
 
 #[deriving(Clone, Eq, Encodable, Decodable, IterBytes)]
 pub enum float_ty {
-    ty_f,
     ty_f32,
     ty_f64,
 }
diff --git a/src/libsyntax/ast_util.rs b/src/libsyntax/ast_util.rs
index f93fc1e81da..12ad7111f7f 100644
--- a/src/libsyntax/ast_util.rs
+++ b/src/libsyntax/ast_util.rs
@@ -190,7 +190,7 @@ pub fn uint_ty_max(t: uint_ty) -> u64 {
 }
 
 pub fn float_ty_to_str(t: float_ty) -> ~str {
-    match t { ty_f => ~"f", ty_f32 => ~"f32", ty_f64 => ~"f64" }
+    match t { ty_f32 => ~"f32", ty_f64 => ~"f64" }
 }
 
 pub fn is_call_expr(e: @Expr) -> bool {
diff --git a/src/libsyntax/ext/quote.rs b/src/libsyntax/ext/quote.rs
index 24a5f9d5e3c..bfd1e9cc994 100644
--- a/src/libsyntax/ext/quote.rs
+++ b/src/libsyntax/ext/quote.rs
@@ -446,7 +446,6 @@ fn mk_token(cx: @ExtCtxt, sp: Span, tok: &token::Token) -> @ast::Expr {
 
         LIT_FLOAT(fident, fty) => {
             let s_fty = match fty {
-                ast::ty_f => ~"ty_f",
                 ast::ty_f32 => ~"ty_f32",
                 ast::ty_f64 => ~"ty_f64"
             };
diff --git a/src/libsyntax/parse/lexer.rs b/src/libsyntax/parse/lexer.rs
index 640c7c220e5..4a384f864b0 100644
--- a/src/libsyntax/parse/lexer.rs
+++ b/src/libsyntax/parse/lexer.rs
@@ -530,7 +530,6 @@ fn scan_number(c: char, rdr: @mut StringReader) -> token::Token {
       None => ()
     }
 
-    let mut is_machine_float = false;
     if rdr.curr == 'f' {
         bump(rdr);
         c = rdr.curr;
@@ -549,14 +548,10 @@ fn scan_number(c: char, rdr: @mut StringReader) -> token::Token {
             32-bit or 64-bit float, it won't be noticed till the
             back-end.  */
         } else {
-            is_float = true;
-            is_machine_float = true;
+            fatal_span(rdr, start_bpos, rdr.last_pos, ~"expected `f32` or `f64` suffix");
         }
     }
     if is_float {
-        if is_machine_float {
-            return token::LIT_FLOAT(str_to_ident(num_str), ast::ty_f);
-        }
         return token::LIT_FLOAT_UNSUFFIXED(str_to_ident(num_str));
     } else {
         if num_str.len() == 0u {