Add `to_symbol` methods.

Cargo.lock

@@ -3009,6 +3009,7 @@ dependencies = [
  "rustc_cratesio_shim 0.0.0",
  "rustc_data_structures 0.0.0",
  "serialize 0.0.0",
+ "syntax_pos 0.0.0",
 ]
 
 [[package]]

src/librustc_target/Cargo.toml

@@ -15,3 +15,4 @@ log = "0.4"
 rustc_cratesio_shim = { path = "../librustc_cratesio_shim" }
 rustc_data_structures = { path = "../librustc_data_structures" }
 serialize = { path = "../libserialize" }
+syntax_pos = { path = "../libsyntax_pos" }

src/librustc_target/abi/mod.rs

@@ -7,6 +7,7 @@ use std::fmt;
 use std::ops::{Add, Deref, Sub, Mul, AddAssign, Range, RangeInclusive};
 
 use rustc_data_structures::indexed_vec::{Idx, IndexVec};
+use syntax_pos::symbol::{sym, Symbol};
 
 pub mod call;
 
@@ -552,6 +553,13 @@ impl FloatTy {
         }
     }
 
+    pub fn to_symbol(self) -> Symbol {
+        match self {
+            FloatTy::F32 => sym::f32,
+            FloatTy::F64 => sym::f64,
+        }
+    }
+
     pub fn bit_width(self) -> usize {
         match self {
             FloatTy::F32 => 32,

src/libsyntax/ast.rs

@@ -10,7 +10,7 @@ use crate::parse::token;
 use crate::print::pprust;
 use crate::ptr::P;
 use crate::source_map::{dummy_spanned, respan, Spanned};
-use crate::symbol::{kw, Symbol};
+use crate::symbol::{kw, sym, Symbol};
 use crate::tokenstream::TokenStream;
 use crate::ThinVec;
 
@@ -1531,6 +1531,17 @@ impl IntTy {
         }
     }
 
+    pub fn to_symbol(&self) -> Symbol {
+        match *self {
+            IntTy::Isize => sym::isize,
+            IntTy::I8 => sym::i8,
+            IntTy::I16 => sym::i16,
+            IntTy::I32 => sym::i32,
+            IntTy::I64 => sym::i64,
+            IntTy::I128 => sym::i128,
+        }
+    }
+
     pub fn val_to_string(&self, val: i128) -> String {
         // Cast to a `u128` so we can correctly print `INT128_MIN`. All integral types
         // are parsed as `u128`, so we wouldn't want to print an extra negative
@@ -1572,6 +1583,17 @@ impl UintTy {
         }
     }
 
+    pub fn to_symbol(&self) -> Symbol {
+        match *self {
+            UintTy::Usize => sym::usize,
+            UintTy::U8 => sym::u8,
+            UintTy::U16 => sym::u16,
+            UintTy::U32 => sym::u32,
+            UintTy::U64 => sym::u64,
+            UintTy::U128 => sym::u128,
+        }
+    }
+
     pub fn val_to_string(&self, val: u128) -> String {
         format!("{}{}", val, self.ty_to_string())
     }

src/libsyntax/parse/literal.rs

@@ -193,14 +193,14 @@ impl LitKind {
             }
             LitKind::Int(n, ty) => {
                 let suffix = match ty {
-                    ast::LitIntType::Unsigned(ty) => Some(Symbol::intern(ty.ty_to_string())),
-                    ast::LitIntType::Signed(ty) => Some(Symbol::intern(ty.ty_to_string())),
+                    ast::LitIntType::Unsigned(ty) => Some(ty.to_symbol()),
+                    ast::LitIntType::Signed(ty) => Some(ty.to_symbol()),
                     ast::LitIntType::Unsuffixed => None,
                 };
                 (token::Integer, sym::integer(n), suffix)
             }
             LitKind::Float(symbol, ty) => {
-                (token::Float, symbol, Some(Symbol::intern(ty.ty_to_string())))
+                (token::Float, symbol, Some(ty.to_symbol()))
             }
             LitKind::FloatUnsuffixed(symbol) => {
                 (token::Float, symbol, None)