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Merged
merged 4 commits into from Nov 16, 2014
Merged

Remove unit #18752

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08d6774
Try to remove ty_nil, some kind of error in exhaustiveness checking
nikomatsakis Nov 4, 2014
eb01b17
Complete the removal of ty_nil, ast::LitNil, ast::TyBot and ast::TyUniq
Nov 9, 2014
28b1b2e
Update tests accordingly
Nov 9, 2014
c425ed2
Update the reference
Nov 9, 2014
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12 changes: 8 additions & 4 deletions src/doc/reference.md
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Expand Up @@ -458,10 +458,9 @@ Examples of floating-point literals of various forms:
12E+99_f64; // type f64
```

##### Unit and boolean literals
##### Boolean literals

The _unit value_, the only value of the type that has the same name, is written
as `()`. The two values of the boolean type are written `true` and `false`.
The two values of the boolean type are written `true` and `false`.

### Symbols

Expand Down Expand Up @@ -2717,7 +2716,7 @@ or an item. Path expressions are [lvalues](#lvalues,-rvalues-and-temporaries).

### Tuple expressions

Tuples are written by enclosing one or more comma-separated expressions in
Tuples are written by enclosing zero or more comma-separated expressions in
parentheses. They are used to create [tuple-typed](#tuple-types) values.

```{.tuple}
Expand All @@ -2726,6 +2725,11 @@ parentheses. They are used to create [tuple-typed](#tuple-types) values.
("a", 4u, true);
```

### Unit expressions

The expression `()` denotes the _unit value_, the only value of the type with
the same name.

### Structure expressions

```{.ebnf .gram}
Expand Down
1 change: 0 additions & 1 deletion src/librustc/diagnostics.rs
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Expand Up @@ -66,7 +66,6 @@ register_diagnostics!(
E0055,
E0056,
E0057,
E0058,
E0059,
E0060,
E0061,
Expand Down
7 changes: 5 additions & 2 deletions src/librustc/lint/builtin.rs
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Expand Up @@ -447,7 +447,9 @@ impl LintPass for ImproperCTypes {
for input in decl.inputs.iter() {
check_ty(cx, &*input.ty);
}
check_ty(cx, &*decl.output)
if let ast::Return(ref ret_ty) = decl.output {
check_ty(cx, &**ret_ty);
}
}

match it.node {
Expand Down Expand Up @@ -735,7 +737,8 @@ impl LintPass for UnusedResults {
let t = ty::expr_ty(cx.tcx, expr);
let mut warned = false;
match ty::get(t).sty {
ty::ty_nil | ty::ty_bool => return,
ty::ty_tup(ref tys) if tys.is_empty() => return,
ty::ty_bool => return,
ty::ty_struct(did, _) |
ty::ty_enum(did, _) => {
if ast_util::is_local(did) {
Expand Down
1 change: 0 additions & 1 deletion src/librustc/metadata/tydecode.rs
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Expand Up @@ -360,7 +360,6 @@ fn parse_trait_ref(st: &mut PState, conv: conv_did) -> ty::TraitRef {

fn parse_ty(st: &mut PState, conv: conv_did) -> ty::t {
match next(st) {
'n' => return ty::mk_nil(),
'b' => return ty::mk_bool(),
'i' => return ty::mk_int(),
'u' => return ty::mk_uint(),
Expand Down
1 change: 0 additions & 1 deletion src/librustc/metadata/tyencode.rs
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Expand Up @@ -199,7 +199,6 @@ pub fn enc_trait_store(w: &mut SeekableMemWriter, cx: &ctxt, s: ty::TraitStore)

fn enc_sty(w: &mut SeekableMemWriter, cx: &ctxt, st: &ty::sty) {
match *st {
ty::ty_nil => mywrite!(w, "n"),
ty::ty_bool => mywrite!(w, "b"),
ty::ty_char => mywrite!(w, "c"),
ty::ty_int(t) => {
Expand Down
8 changes: 2 additions & 6 deletions src/librustc/middle/check_match.rs
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Expand Up @@ -8,7 +8,7 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.

use middle::const_eval::{compare_const_vals, const_bool, const_float, const_nil, const_val};
use middle::const_eval::{compare_const_vals, const_bool, const_float, const_val};
use middle::const_eval::{const_expr_to_pat, eval_const_expr, lookup_const_by_id};
use middle::def::*;
use middle::expr_use_visitor::{ConsumeMode, Delegate, ExprUseVisitor, Init};
Expand Down Expand Up @@ -332,7 +332,6 @@ fn check_exhaustive(cx: &MatchCheckCtxt, sp: Span, matrix: &Matrix) {
fn const_val_to_expr(value: &const_val) -> P<Expr> {
let node = match value {
&const_bool(b) => LitBool(b),
&const_nil => LitNil,
_ => unreachable!()
};
P(Expr {
Expand Down Expand Up @@ -497,9 +496,6 @@ fn all_constructors(cx: &MatchCheckCtxt, left_ty: ty::t,
ty::ty_bool =>
[true, false].iter().map(|b| ConstantValue(const_bool(*b))).collect(),

ty::ty_nil =>
vec!(ConstantValue(const_nil)),

ty::ty_rptr(_, ty::mt { ty, .. }) => match ty::get(ty).sty {
ty::ty_vec(_, None) =>
range_inclusive(0, max_slice_length).map(|length| Slice(length)).collect(),
Expand Down Expand Up @@ -552,7 +548,7 @@ fn is_useful(cx: &MatchCheckCtxt,
None => v[0]
};
let left_ty = if real_pat.id == DUMMY_NODE_ID {
ty::mk_nil()
ty::mk_nil(cx.tcx)
} else {
ty::pat_ty(cx.tcx, &*real_pat)
};
Expand Down
5 changes: 1 addition & 4 deletions src/librustc/middle/const_eval.rs
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Expand Up @@ -311,8 +311,7 @@ pub enum const_val {
const_uint(u64),
const_str(InternedString),
const_binary(Rc<Vec<u8> >),
const_bool(bool),
const_nil
const_bool(bool)
}

pub fn const_expr_to_pat(tcx: &ty::ctxt, expr: &Expr) -> P<Pat> {
Expand Down Expand Up @@ -589,7 +588,6 @@ pub fn lit_to_const(lit: &Lit) -> const_val {
LitFloatUnsuffixed(ref n) => {
const_float(from_str::<f64>(n.get()).unwrap() as f64)
}
LitNil => const_nil,
LitBool(b) => const_bool(b)
}
}
Expand All @@ -605,7 +603,6 @@ pub fn compare_const_vals(a: &const_val, b: &const_val) -> Option<int> {
(&const_str(ref a), &const_str(ref b)) => compare_vals(a, b),
(&const_bool(a), &const_bool(b)) => compare_vals(a, b),
(&const_binary(ref a), &const_binary(ref b)) => compare_vals(a, b),
(&const_nil, &const_nil) => compare_vals((), ()),
_ => None
}
}
Expand Down
8 changes: 6 additions & 2 deletions src/librustc/middle/resolve.rs
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Expand Up @@ -4285,7 +4285,9 @@ impl<'a> Resolver<'a> {
_ => {}
}

this.resolve_type(&*ty_m.decl.output);
if let ast::Return(ref ret_ty) = ty_m.decl.output {
this.resolve_type(&**ret_ty);
}
});
}
ast::ProvidedMethod(ref m) => {
Expand Down Expand Up @@ -4467,7 +4469,9 @@ impl<'a> Resolver<'a> {
debug!("(resolving function) recorded argument");
}

this.resolve_type(&*declaration.output);
if let ast::Return(ref ret_ty) = declaration.output {
this.resolve_type(&**ret_ty);
}
}
}

Expand Down
21 changes: 17 additions & 4 deletions src/librustc/middle/save/mod.rs
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Expand Up @@ -383,7 +383,11 @@ impl <'l, 'tcx> DxrVisitor<'l, 'tcx> {
for arg in method.pe_fn_decl().inputs.iter() {
self.visit_ty(&*arg.ty);
}
self.visit_ty(&*method.pe_fn_decl().output);

if let ast::Return(ref ret_ty) = method.pe_fn_decl().output {
self.visit_ty(&**ret_ty);
}

// walk the fn body
self.nest(method.id, |v| v.visit_block(&*method.pe_body()));

Expand Down Expand Up @@ -491,7 +495,10 @@ impl <'l, 'tcx> DxrVisitor<'l, 'tcx> {
for arg in decl.inputs.iter() {
self.visit_ty(&*arg.ty);
}
self.visit_ty(&*decl.output);

if let ast::Return(ref ret_ty) = decl.output {
self.visit_ty(&**ret_ty);
}

// walk the body
self.nest(item.id, |v| v.visit_block(&*body));
Expand Down Expand Up @@ -1136,7 +1143,10 @@ impl<'l, 'tcx, 'v> Visitor<'v> for DxrVisitor<'l, 'tcx> {
for arg in method_type.decl.inputs.iter() {
self.visit_ty(&*arg.ty);
}
self.visit_ty(&*method_type.decl.output);

if let ast::Return(ref ret_ty) = method_type.decl.output {
self.visit_ty(&**ret_ty);
}

self.process_generic_params(&method_type.generics,
method_type.span,
Expand Down Expand Up @@ -1352,7 +1362,10 @@ impl<'l, 'tcx, 'v> Visitor<'v> for DxrVisitor<'l, 'tcx> {
for arg in decl.inputs.iter() {
self.visit_ty(&*arg.ty);
}
self.visit_ty(&*decl.output);

if let ast::Return(ref ret_ty) = decl.output {
self.visit_ty(&**ret_ty);
}

// walk the body
self.nest(ex.id, |v| v.visit_block(&**body));
Expand Down
1 change: 0 additions & 1 deletion src/librustc/middle/traits/coherence.rs
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Expand Up @@ -79,7 +79,6 @@ pub fn ty_is_local(tcx: &ty::ctxt,
debug!("ty_is_local({})", ty.repr(tcx));

match ty::get(ty).sty {
ty::ty_nil |
ty::ty_bool |
ty::ty_char |
ty::ty_int(..) |
Expand Down
1 change: 0 additions & 1 deletion src/librustc/middle/traits/select.rs
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Expand Up @@ -1227,7 +1227,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
ty::ty_infer(ty::FloatVar(_)) |
ty::ty_uint(_) |
ty::ty_int(_) |
ty::ty_nil |
ty::ty_bool |
ty::ty_float(_) |
ty::ty_bare_fn(_) |
Expand Down
2 changes: 1 addition & 1 deletion src/librustc/middle/trans/_match.rs
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Expand Up @@ -1012,7 +1012,7 @@ fn compile_submatch_continue<'a, 'p, 'blk, 'tcx>(mut bcx: Block<'blk, 'tcx>,
.unwrap_or(DUMMY_NODE_ID);

let left_ty = if pat_id == DUMMY_NODE_ID {
ty::mk_nil()
ty::mk_nil(tcx)
} else {
node_id_type(bcx, pat_id)
};
Expand Down
22 changes: 6 additions & 16 deletions src/librustc/middle/trans/base.rs
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Expand Up @@ -47,7 +47,7 @@ use middle::trans::builder::{Builder, noname};
use middle::trans::callee;
use middle::trans::cleanup::{CleanupMethods, ScopeId};
use middle::trans::cleanup;
use middle::trans::common::{Block, C_bool, C_bytes_in_context, C_i32, C_integral, C_nil};
use middle::trans::common::{Block, C_bool, C_bytes_in_context, C_i32, C_integral};
use middle::trans::common::{C_null, C_struct_in_context, C_u64, C_u8, C_uint, C_undef};
use middle::trans::common::{CrateContext, ExternMap, FunctionContext};
use middle::trans::common::{NodeInfo, Result, SubstP};
Expand Down Expand Up @@ -517,7 +517,7 @@ pub fn get_res_dtor(ccx: &CrateContext,
let class_ty = ty::lookup_item_type(tcx, parent_id).ty.subst(tcx, substs);
let llty = type_of_dtor(ccx, class_ty);
let dtor_ty = ty::mk_ctor_fn(ccx.tcx(), ast::DUMMY_NODE_ID,
[glue::get_drop_glue_type(ccx, t)], ty::mk_nil());
[glue::get_drop_glue_type(ccx, t)], ty::mk_nil(ccx.tcx()));
get_extern_fn(ccx,
&mut *ccx.externs().borrow_mut(),
name.as_slice(),
Expand Down Expand Up @@ -551,7 +551,7 @@ pub fn compare_scalar_types<'blk, 'tcx>(cx: Block<'blk, 'tcx>,
let f = |a| Result::new(cx, compare_scalar_values(cx, lhs, rhs, a, op));

match ty::get(t).sty {
ty::ty_nil => f(nil_type),
ty::ty_tup(ref tys) if tys.is_empty() => f(nil_type),
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Is this used often enough to have it special-cased in the compiler?

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In explicit code most likely not but I'd imagine it being used all over the place after monomorphization.

ty::ty_bool | ty::ty_uint(_) | ty::ty_char => f(unsigned_int),
ty::ty_ptr(mt) if ty::type_is_sized(cx.tcx(), mt.ty) => f(unsigned_int),
ty::ty_int(_) => f(signed_int),
Expand Down Expand Up @@ -1578,12 +1578,6 @@ fn create_datums_for_fn_args_under_call_abi(
"argtuple"));
result.push(tuple);
}
ty::ty_nil => {
let mode = datum::Rvalue::new(datum::ByValue);
result.push(datum::Datum::new(C_nil(bcx.ccx()),
ty::mk_nil(),
mode))
}
_ => {
bcx.tcx().sess.bug("last argument of a function with \
`rust-call` ABI isn't a tuple?!")
Expand Down Expand Up @@ -1647,10 +1641,8 @@ fn copy_unboxed_closure_args_to_allocas<'blk, 'tcx>(
arg_datum.to_lvalue_datum_in_scope(bcx,
"argtuple",
arg_scope_id));
let empty = Vec::new();
let untupled_arg_types = match ty::get(monomorphized_arg_types[0]).sty {
ty::ty_tup(ref types) => types.as_slice(),
ty::ty_nil => empty.as_slice(),
_ => {
bcx.tcx().sess.span_bug(args[0].pat.span,
"first arg to `rust-call` ABI function \
Expand Down Expand Up @@ -1824,7 +1816,7 @@ pub fn trans_closure(ccx: &CrateContext,
NotUnboxedClosure => monomorphized_arg_types,

// Tuple up closure argument types for the "rust-call" ABI.
IsUnboxedClosure => vec![ty::mk_tup_or_nil(ccx.tcx(), monomorphized_arg_types)]
IsUnboxedClosure => vec![ty::mk_tup(ccx.tcx(), monomorphized_arg_types)]
};
for monomorphized_arg_type in monomorphized_arg_types.iter() {
debug!("trans_closure: monomorphized_arg_type: {}",
Expand Down Expand Up @@ -2380,7 +2372,6 @@ pub fn get_fn_llvm_attributes(ccx: &CrateContext, fn_ty: ty::t)
assert!(abi == RustCall);

match ty::get(fn_sig.inputs[0]).sty {
ty::ty_nil => Vec::new(),
ty::ty_tup(ref inputs) => inputs.clone(),
_ => ccx.sess().bug("expected tuple'd inputs")
}
Expand All @@ -2389,7 +2380,6 @@ pub fn get_fn_llvm_attributes(ccx: &CrateContext, fn_ty: ty::t)
let mut inputs = vec![fn_sig.inputs[0]];

match ty::get(fn_sig.inputs[1]).sty {
ty::ty_nil => inputs,
ty::ty_tup(ref t_in) => {
inputs.push_all(t_in.as_slice());
inputs
Expand Down Expand Up @@ -2532,7 +2522,7 @@ pub fn register_fn_llvmty(ccx: &CrateContext,
llfty: Type) -> ValueRef {
debug!("register_fn_llvmty id={} sym={}", node_id, sym);

let llfn = decl_fn(ccx, sym.as_slice(), cc, llfty, ty::FnConverging(ty::mk_nil()));
let llfn = decl_fn(ccx, sym.as_slice(), cc, llfty, ty::FnConverging(ty::mk_nil(ccx.tcx())));
finish_register_fn(ccx, sp, sym, node_id, llfn);
llfn
}
Expand Down Expand Up @@ -2564,7 +2554,7 @@ pub fn create_entry_wrapper(ccx: &CrateContext,
let llfty = Type::func([ccx.int_type(), Type::i8p(ccx).ptr_to()],
&ccx.int_type());

let llfn = decl_cdecl_fn(ccx, "main", llfty, ty::mk_nil());
let llfn = decl_cdecl_fn(ccx, "main", llfty, ty::mk_nil(ccx.tcx()));

// FIXME: #16581: Marking a symbol in the executable with `dllexport`
// linkage forces MinGW's linker to output a `.reloc` section for ASLR
Expand Down
4 changes: 1 addition & 3 deletions src/librustc/middle/trans/callee.rs
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Expand Up @@ -764,7 +764,7 @@ pub fn trans_call_inner<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
expr::Ignore => {
let ret_ty = match ret_ty {
ty::FnConverging(ret_ty) => ret_ty,
ty::FnDiverging => ty::mk_nil()
ty::FnDiverging => ty::mk_nil(ccx.tcx())
};
if !is_rust_fn ||
type_of::return_uses_outptr(ccx, ret_ty) ||
Expand Down Expand Up @@ -957,7 +957,6 @@ fn trans_args_under_call_abi<'blk, 'tcx>(
llargs.push(arg_datum.add_clean(bcx.fcx, arg_cleanup_scope));
}
}
ty::ty_nil => {}
_ => {
bcx.sess().span_bug(tuple_expr.span,
"argument to `.call()` wasn't a tuple?!")
Expand Down Expand Up @@ -1004,7 +1003,6 @@ fn trans_overloaded_call_args<'blk, 'tcx>(
}))
}
}
ty::ty_nil => {}
_ => {
bcx.sess().span_bug(arg_exprs[0].span,
"argument to `.call()` wasn't a tuple?!")
Expand Down
1 change: 0 additions & 1 deletion src/librustc/middle/trans/consts.rs
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Expand Up @@ -81,7 +81,6 @@ pub fn const_lit(cx: &CrateContext, e: &ast::Expr, lit: &ast::Lit)
}
}
ast::LitBool(b) => C_bool(cx, b),
ast::LitNil => C_nil(cx),
ast::LitStr(ref s, _) => C_str_slice(cx, (*s).clone()),
ast::LitBinary(ref data) => C_binary_slice(cx, data.as_slice()),
}
Expand Down
8 changes: 5 additions & 3 deletions src/librustc/middle/trans/context.rs
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Expand Up @@ -718,15 +718,17 @@ fn declare_intrinsic(ccx: &CrateContext, key: & &'static str) -> Option<ValueRef
macro_rules! ifn (
($name:expr fn() -> $ret:expr) => (
if *key == $name {
let f = base::decl_cdecl_fn(ccx, $name, Type::func([], &$ret), ty::mk_nil());
let f = base::decl_cdecl_fn(
ccx, $name, Type::func([], &$ret),
ty::mk_nil(ccx.tcx()));
ccx.intrinsics().borrow_mut().insert($name, f.clone());
return Some(f);
}
);
($name:expr fn($($arg:expr),*) -> $ret:expr) => (
if *key == $name {
let f = base::decl_cdecl_fn(ccx, $name,
Type::func([$($arg),*], &$ret), ty::mk_nil());
Type::func([$($arg),*], &$ret), ty::mk_nil(ccx.tcx()));
ccx.intrinsics().borrow_mut().insert($name, f.clone());
return Some(f);
}
Expand Down Expand Up @@ -863,7 +865,7 @@ fn declare_intrinsic(ccx: &CrateContext, key: & &'static str) -> Option<ValueRef
} else if *key == $name {
let f = base::decl_cdecl_fn(ccx, stringify!($cname),
Type::func([$($arg),*], &$ret),
ty::mk_nil());
ty::mk_nil(ccx.tcx()));
ccx.intrinsics().borrow_mut().insert($name, f.clone());
return Some(f);
}
Expand Down
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