rustc: Implement floating point literal inference. r=nmatsakis

Author: pcwalton

src/librustc/metadata/tyencode.rs

@@ -286,6 +286,11 @@ fn enc_sty(w: io::Writer, cx: @ctxt, st: ty::sty) {
         w.write_char('I');
         w.write_uint(id.to_uint());
       }
+      ty::ty_infer(ty::FloatVar(id)) => {
+        w.write_char('X');
+        w.write_char('F');
+        w.write_uint(id.to_uint());
+      }
       ty::ty_param({idx: id, def_id: did}) => {
         w.write_char('p');
         w.write_str(cx.ds(did));

src/librustc/middle/const_eval.rs

@@ -389,6 +389,8 @@ fn lit_to_const(lit: @lit) -> const_val {
       lit_uint(n, _) => const_uint(n),
       lit_int_unsuffixed(n) => const_int(n),
       lit_float(n, _) => const_float(float::from_str(*n).get() as f64),
+      lit_float_unsuffixed(n) =>
+        const_float(float::from_str(*n).get() as f64),
       lit_nil => const_int(0i64),
       lit_bool(b) => const_bool(b)
     }

src/librustc/middle/trans/consts.rs

@@ -22,6 +22,19 @@ fn const_lit(cx: @crate_ctxt, e: @ast::expr, lit: ast::lit)
         }
       }
       ast::lit_float(fs, t) => C_floating(*fs, T_float_ty(cx, t)),
+      ast::lit_float_unsuffixed(fs) => {
+        let lit_float_ty = ty::node_id_to_type(cx.tcx, e.id);
+        match ty::get(lit_float_ty).sty {
+          ty::ty_float(t) => {
+            C_floating(*fs, T_float_ty(cx, t))
+          }
+          _ => {
+            cx.sess.span_bug(lit.span,
+                             ~"floating point literal doesn't have the right \
+                               type");
+          }
+        }
+      }
       ast::lit_bool(b) => C_bool(b),
       ast::lit_nil => C_nil(),
       ast::lit_str(s) => C_estr_slice(cx, *s)

src/librustc/middle/ty.rs

@@ -21,7 +21,7 @@ use util::ppaux::{ty_to_str, proto_ty_to_str, tys_to_str};
 
 export ProvidedMethodSource;
 export InstantiatedTraitRef;
-export TyVid, IntVid, FnVid, RegionVid, vid;
+export TyVid, IntVid, FloatVid, FnVid, RegionVid, vid;
 export br_hashmap;
 export is_instantiable;
 export node_id_to_type;
@@ -86,6 +86,7 @@ export ty_fn, FnTy, FnTyBase, FnMeta, FnSig, mk_fn;
 export ty_fn_proto, ty_fn_purity, ty_fn_ret, ty_fn_ret_style, tys_in_fn_ty;
 export ty_int, mk_int, mk_mach_int, mk_char;
 export mk_i8, mk_u8, mk_i16, mk_u16, mk_i32, mk_u32, mk_i64, mk_u64;
+export mk_f32, mk_f64;
 export ty_estr, mk_estr, type_is_str;
 export ty_evec, mk_evec, type_is_vec;
 export ty_unboxed_vec, mk_unboxed_vec, mk_mut_unboxed_vec;
@@ -102,8 +103,8 @@ export ty_tup, mk_tup;
 export ty_type, mk_type;
 export ty_uint, mk_uint, mk_mach_uint;
 export ty_uniq, mk_uniq, mk_imm_uniq, type_is_unique_box;
-export ty_infer, mk_infer, type_is_ty_var, mk_var, mk_int_var;
-export InferTy, TyVar, IntVar;
+export ty_infer, mk_infer, type_is_ty_var, mk_var, mk_int_var, mk_float_var;
+export InferTy, TyVar, IntVar, FloatVar;
 export ty_self, mk_self, type_has_self;
 export ty_class;
 export Region, bound_region, encl_region;
@@ -172,7 +173,8 @@ export ty_sort_str;
 export normalize_ty;
 export to_str;
 export bound_const;
-export terr_no_integral_type, terr_ty_param_size, terr_self_substs;
+export terr_no_integral_type, terr_no_floating_point_type;
+export terr_ty_param_size, terr_self_substs;
 export terr_in_field, terr_record_fields, terr_vstores_differ, terr_arg_count;
 export terr_sorts, terr_vec, terr_str, terr_record_size, terr_tuple_size;
 export terr_regions_does_not_outlive, terr_mutability, terr_purity_mismatch;
@@ -666,6 +668,7 @@ enum type_err {
     terr_sorts(expected_found<t>),
     terr_self_substs,
     terr_no_integral_type,
+    terr_no_floating_point_type,
 }
 
 enum param_bound {
@@ -678,21 +681,24 @@ enum param_bound {
 
 enum TyVid = uint;
 enum IntVid = uint;
+enum FloatVid = uint;
 enum FnVid = uint;
 #[auto_serialize]
 #[auto_deserialize]
 enum RegionVid = uint;
 
 enum InferTy {
     TyVar(TyVid),
-    IntVar(IntVid)
+    IntVar(IntVid),
+    FloatVar(FloatVid)
 }
 
 impl InferTy : to_bytes::IterBytes {
     pure fn iter_bytes(+lsb0: bool, f: to_bytes::Cb) {
         match self {
           TyVar(ref tv) => to_bytes::iter_bytes_2(&0u8, tv, lsb0, f),
-          IntVar(ref iv) => to_bytes::iter_bytes_2(&1u8, iv, lsb0, f)
+          IntVar(ref iv) => to_bytes::iter_bytes_2(&1u8, iv, lsb0, f),
+          FloatVar(ref fv) => to_bytes::iter_bytes_2(&2u8, fv, lsb0, f)
         }
     }
 }
@@ -758,6 +764,11 @@ impl IntVid: vid {
     pure fn to_str() -> ~str { fmt!("<VI%u>", self.to_uint()) }
 }
 
+impl FloatVid: vid {
+    pure fn to_uint() -> uint { *self }
+    pure fn to_str() -> ~str { fmt!("<VF%u>", self.to_uint()) }
+}
+
 impl FnVid: vid {
     pure fn to_uint() -> uint { *self }
     pure fn to_str() -> ~str { fmt!("<F%u>", self.to_uint()) }
@@ -773,13 +784,15 @@ impl InferTy {
         match self {
             TyVar(v) => v.to_uint() << 1,
             IntVar(v) => (v.to_uint() << 1) + 1,
+            FloatVar(v) => (v.to_uint() << 1) + 2
         }
     }
 
     pure fn to_str() -> ~str {
         match self {
             TyVar(v) => v.to_str(),
             IntVar(v) => v.to_str(),
+            FloatVar(v) => v.to_str()
         }
     }
 }
@@ -812,6 +825,12 @@ impl IntVid : to_bytes::IterBytes {
     }
 }
 
+impl FloatVid : to_bytes::IterBytes {
+    pure fn iter_bytes(+lsb0: bool, f: to_bytes::Cb) {
+        (*self).iter_bytes(lsb0, f)
+    }
+}
+
 impl FnVid : to_bytes::IterBytes {
     pure fn iter_bytes(+lsb0: bool, f: to_bytes::Cb) {
         (*self).iter_bytes(lsb0, f)
@@ -1030,6 +1049,10 @@ fn mk_u32(cx: ctxt) -> t { mk_t(cx, ty_uint(ast::ty_u32)) }
 
 fn mk_u64(cx: ctxt) -> t { mk_t(cx, ty_uint(ast::ty_u64)) }
 
+fn mk_f32(cx: ctxt) -> t { mk_t(cx, ty_float(ast::ty_f32)) }
+
+fn mk_f64(cx: ctxt) -> t { mk_t(cx, ty_float(ast::ty_f64)) }
+
 fn mk_mach_int(cx: ctxt, tm: ast::int_ty) -> t { mk_t(cx, ty_int(tm)) }
 
 fn mk_mach_uint(cx: ctxt, tm: ast::uint_ty) -> t { mk_t(cx, ty_uint(tm)) }
@@ -1110,9 +1133,9 @@ fn mk_class(cx: ctxt, class_id: ast::def_id, +substs: substs) -> t {
 
 fn mk_var(cx: ctxt, v: TyVid) -> t { mk_infer(cx, TyVar(v)) }
 
-fn mk_int_var(cx: ctxt, v: IntVid) -> t {
-    mk_infer(cx, IntVar(v))
-}
+fn mk_int_var(cx: ctxt, v: IntVid) -> t { mk_infer(cx, IntVar(v)) }
+
+fn mk_float_var(cx: ctxt, v: FloatVid) -> t { mk_infer(cx, FloatVar(v)) }
 
 fn mk_infer(cx: ctxt, it: InferTy) -> t { mk_t(cx, ty_infer(it)) }
 
@@ -1661,7 +1684,8 @@ pure fn type_is_unique(ty: t) -> bool {
 pure fn type_is_scalar(ty: t) -> bool {
     match get(ty).sty {
       ty_nil | ty_bool | ty_int(_) | ty_float(_) | ty_uint(_) |
-      ty_infer(IntVar(_)) | ty_type | ty_ptr(_) => true,
+      ty_infer(IntVar(_)) | ty_infer(FloatVar(_)) | ty_type |
+      ty_ptr(_) => true,
       _ => false
     }
 }
@@ -2428,7 +2452,7 @@ fn type_is_integral(ty: t) -> bool {
 
 fn type_is_fp(ty: t) -> bool {
     match get(ty).sty {
-      ty_float(_) => true,
+      ty_infer(FloatVar(_)) | ty_float(_) => true,
       _ => false
     }
 }
@@ -3260,6 +3284,7 @@ fn ty_sort_str(cx: ctxt, t: t) -> ~str {
       ty_tup(_) => ~"tuple",
       ty_infer(TyVar(_)) => ~"inferred type",
       ty_infer(IntVar(_)) => ~"integral variable",
+      ty_infer(FloatVar(_)) => ~"floating-point variable",
       ty_param(_) => ~"type parameter",
       ty_self => ~"self"
     }
@@ -3387,6 +3412,10 @@ fn type_err_to_str(cx: ctxt, err: &type_err) -> ~str {
             ~"couldn't determine an appropriate integral type for integer \
               literal"
         }
+        terr_no_floating_point_type => {
+            ~"couldn't determine an appropriate floating point type for \
+              floating point literal"
+        }
     }
 }
 
@@ -4000,7 +4029,7 @@ fn is_binopable(_cx: ctxt, ty: t, op: ast::binop) -> bool {
         match get(ty).sty {
           ty_bool => tycat_bool,
           ty_int(_) | ty_uint(_) | ty_infer(IntVar(_)) => tycat_int,
-          ty_float(_) => tycat_float,
+          ty_float(_) | ty_infer(FloatVar(_)) => tycat_float,
           ty_rec(_) | ty_tup(_) | ty_enum(_, _) => tycat_struct,
           ty_bot => tycat_bot,
           _ => tycat_other
@@ -4230,6 +4259,11 @@ impl IntVid : cmp::Eq {
     pure fn ne(other: &IntVid) -> bool { *self != *(*other) }
 }
 
+impl FloatVid : cmp::Eq {
+    pure fn eq(other: &FloatVid) -> bool { *self == *(*other) }
+    pure fn ne(other: &FloatVid) -> bool { *self != *(*other) }
+}
+
 impl FnVid : cmp::Eq {
     pure fn eq(other: &FnVid) -> bool { *self == *(*other) }
     pure fn ne(other: &FnVid) -> bool { *self != *(*other) }

src/librustc/middle/typeck/check.rs

@@ -850,6 +850,11 @@ fn check_lit(fcx: @fn_ctxt, lit: @ast::lit) -> ty::t {
         ty::mk_int_var(tcx, fcx.infcx().next_int_var_id())
       }
       ast::lit_float(_, t) => ty::mk_mach_float(tcx, t),
+      ast::lit_float_unsuffixed(_) => {
+        // An unsuffixed floating point literal could have any floating point
+        // type, so we create a floating point type variable for it.
+        ty::mk_float_var(tcx, fcx.infcx().next_float_var_id())
+      }
       ast::lit_nil => ty::mk_nil(tcx),
       ast::lit_bool(_) => ty::mk_bool(tcx)
     }

src/librustc/middle/typeck/check/method.rs

@@ -664,6 +664,7 @@ impl LookupContext {
         match ty::get(self_ty).sty {
             ty_box(*) | ty_uniq(*) | ty_rptr(*) |
             ty_infer(IntVar(_)) | // FIXME(#3211)---should be resolved
+            ty_infer(FloatVar(_)) | // FIXME(#3211)---should be resolved
             ty_self | ty_param(*) | ty_nil | ty_bot | ty_bool |
             ty_int(*) | ty_uint(*) |
             ty_float(*) | ty_enum(*) | ty_ptr(*) | ty_rec(*) |

src/librustc/middle/typeck/infer.rs

@@ -209,6 +209,8 @@ overconstrains the type, it's a type error; if we reach the point at
 which type variables must be resolved and an integral type variable is
 still underconstrained, it defaults to `int` as a last resort.
 
+Floating point types are handled similarly to integral types.
+
 ## GLB/LUB
 
 Computing the greatest-lower-bound and least-upper-bound of two
@@ -250,8 +252,8 @@ use std::smallintmap;
 use std::smallintmap::smallintmap;
 use std::map::HashMap;
 use middle::ty;
-use middle::ty::{TyVid, IntVid, RegionVid, vid,
-                 ty_int, ty_uint, get, terr_fn, TyVar, IntVar};
+use middle::ty::{TyVid, IntVid, FloatVid, RegionVid, vid,
+                 ty_int, ty_uint, get, terr_fn, TyVar, IntVar, FloatVar};
 use syntax::{ast, ast_util};
 use syntax::ast::{ret_style, purity};
 use util::ppaux::{ty_to_str, mt_to_str};
@@ -272,6 +274,7 @@ use resolve::{resolve_nested_tvar, resolve_rvar, resolve_ivar, resolve_all,
                  resolve_and_force_all_but_regions, resolver};
 use unify::{vals_and_bindings, root};
 use integral::{int_ty_set, int_ty_set_all};
+use floating::{float_ty_set, float_ty_set_all};
 use combine::{combine_fields, eq_tys};
 use assignment::Assign;
 use to_str::ToStr;
@@ -318,12 +321,17 @@ enum infer_ctxt = @{
     // represented by an int_ty_set.
     int_var_bindings: vals_and_bindings<ty::IntVid, int_ty_set>,
 
+    // The types that might instantiate a floating-point type variable are
+    // represented by an float_ty_set.
+    float_var_bindings: vals_and_bindings<ty::FloatVid, float_ty_set>,
+
     // For region variables.
     region_vars: RegionVarBindings,
 
     // For keeping track of existing type and region variables.
     ty_var_counter: @mut uint,
     int_var_counter: @mut uint,
+    float_var_counter: @mut uint,
     region_var_counter: @mut uint
 };
 
@@ -359,9 +367,11 @@ fn new_infer_ctxt(tcx: ty::ctxt) -> infer_ctxt {
     infer_ctxt(@{tcx: tcx,
                  ty_var_bindings: new_vals_and_bindings(),
                  int_var_bindings: new_vals_and_bindings(),
+                 float_var_bindings: new_vals_and_bindings(),
                  region_vars: RegionVarBindings(tcx),
                  ty_var_counter: @mut 0u,
                  int_var_counter: @mut 0u,
+                 float_var_counter: @mut 0u,
                  region_var_counter: @mut 0u})}
 
 fn mk_subty(cx: infer_ctxt, a_is_expected: bool, span: span,
@@ -627,6 +637,18 @@ impl infer_ctxt {
         ty::mk_int_var(self.tcx, self.next_int_var_id())
     }
 
+    fn next_float_var_id() -> FloatVid {
+        let id = *self.float_var_counter;
+        *self.float_var_counter += 1;
+
+        self.float_var_bindings.vals.insert(id, root(float_ty_set_all(), 0));
+        return FloatVid(id);
+    }
+
+    fn next_float_var() -> ty::t {
+        ty::mk_float_var(self.tcx, self.next_float_var_id())
+    }
+
     fn next_region_var_nb(span: span) -> ty::Region {
         ty::re_infer(ty::ReVar(self.region_vars.new_region_var(span)))
     }

src/librustc/middle/typeck/infer/combine.rs

@@ -385,6 +385,17 @@ fn super_tys<C:combine>(
         self.infcx().t_sub_int_var(a, b_id).then(|| Ok(a) )
       }
 
+      // Relate floating-point variables to other types
+      (ty::ty_infer(FloatVar(a_id)), ty::ty_infer(FloatVar(b_id))) => {
+        self.infcx().float_vars(a_id, b_id).then(|| Ok(a) )
+      }
+      (ty::ty_infer(FloatVar(a_id)), ty::ty_float(_)) => {
+        self.infcx().float_var_sub_t(a_id, b).then(|| Ok(a) )
+      }
+      (ty::ty_float(_), ty::ty_infer(FloatVar(b_id))) => {
+        self.infcx().t_sub_float_var(a, b_id).then(|| Ok(a) )
+      }
+
       (ty::ty_int(_), _) |
       (ty::ty_uint(_), _) |
       (ty::ty_float(_), _) => {