Improve derived discriminant testing.
Currently the generated code for methods like `eq`, `ne`, and `partial_cmp`
includes stuff like this:
```
let __self_vi = ::core::intrinsics::discriminant_value(&*self);
let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other);
if true && __self_vi == __arg_1_vi {
...
}
```
This commit removes the unnecessary `true &&`, and makes the generating
code a little easier to read in the process. It also fixes some errors
in comments.
This commit is contained in:
Nicholas Nethercote
parent
ea74997c41
commit
00207ead61
@ -1392,37 +1392,32 @@ impl<'a> MethodDef<'a> {
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//
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// i.e., for `enum E<T> { A, B(1), C(T, T) }`, and a deriving
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// with three Self args, builds three statements:
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//
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// ```
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// let __self0_vi = std::intrinsics::discriminant_value(&self);
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// let __self1_vi = std::intrinsics::discriminant_value(&arg1);
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// let __self2_vi = std::intrinsics::discriminant_value(&arg2);
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// let __self_vi = std::intrinsics::discriminant_value(&self);
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// let __arg_1_vi = std::intrinsics::discriminant_value(&arg1);
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// let __arg_2_vi = std::intrinsics::discriminant_value(&arg2);
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// ```
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let mut index_let_stmts: Vec<ast::Stmt> = Vec::with_capacity(vi_idents.len() + 1);
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// We also build an expression which checks whether all discriminants are equal
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// discriminant_test = __self0_vi == __self1_vi && __self0_vi == __self2_vi && ...
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// We also build an expression which checks whether all discriminants are equal:
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// `__self_vi == __arg_1_vi && __self_vi == __arg_2_vi && ...`
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let mut discriminant_test = cx.expr_bool(span, true);
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let mut first_ident = None;
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for (&ident, self_arg) in iter::zip(&vi_idents, &self_args) {
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for (i, (&ident, self_arg)) in iter::zip(&vi_idents, &self_args).enumerate() {
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let self_addr = cx.expr_addr_of(span, self_arg.clone());
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let variant_value =
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deriving::call_intrinsic(cx, span, sym::discriminant_value, vec![self_addr]);
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let let_stmt = cx.stmt_let(span, false, ident, variant_value);
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index_let_stmts.push(let_stmt);
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match first_ident {
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Some(first) => {
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let first_expr = cx.expr_ident(span, first);
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let id = cx.expr_ident(span, ident);
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let test = cx.expr_binary(span, BinOpKind::Eq, first_expr, id);
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discriminant_test =
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cx.expr_binary(span, BinOpKind::And, discriminant_test, test)
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}
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None => {
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first_ident = Some(ident);
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}
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if i > 0 {
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let id0 = cx.expr_ident(span, vi_idents[0]);
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let id = cx.expr_ident(span, ident);
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let test = cx.expr_binary(span, BinOpKind::Eq, id0, id);
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discriminant_test = if i == 1 {
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test
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} else {
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cx.expr_binary(span, BinOpKind::And, discriminant_test, test)
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};
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}
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}
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@ -1453,7 +1448,7 @@ impl<'a> MethodDef<'a> {
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// }
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// }
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// else {
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// <delegated expression referring to __self0_vi, et al.>
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// <delegated expression referring to __self_vi, et al.>
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// }
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let all_match = cx.expr_match(span, match_arg, match_arms);
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let arm_expr = cx.expr_if(span, discriminant_test, all_match, Some(arm_expr));
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@ -648,7 +648,7 @@ impl ::core::cmp::PartialEq for Fieldless {
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{
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let __self_vi = ::core::intrinsics::discriminant_value(&*self);
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let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other);
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if true && __self_vi == __arg_1_vi {
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if __self_vi == __arg_1_vi {
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match (&*self, &*other) { _ => true, }
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} else { false }
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}
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@ -672,7 +672,7 @@ impl ::core::cmp::PartialOrd for Fieldless {
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{
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let __self_vi = ::core::intrinsics::discriminant_value(&*self);
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let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other);
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if true && __self_vi == __arg_1_vi {
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if __self_vi == __arg_1_vi {
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match (&*self, &*other) {
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_ =>
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::core::option::Option::Some(::core::cmp::Ordering::Equal),
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@ -692,7 +692,7 @@ impl ::core::cmp::Ord for Fieldless {
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{
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let __self_vi = ::core::intrinsics::discriminant_value(&*self);
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let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other);
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if true && __self_vi == __arg_1_vi {
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if __self_vi == __arg_1_vi {
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match (&*self, &*other) {
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_ => ::core::cmp::Ordering::Equal,
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}
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@ -783,7 +783,7 @@ impl ::core::cmp::PartialEq for Mixed {
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{
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let __self_vi = ::core::intrinsics::discriminant_value(&*self);
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let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other);
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if true && __self_vi == __arg_1_vi {
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if __self_vi == __arg_1_vi {
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match (&*self, &*other) {
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(&Mixed::R(ref __self_0), &Mixed::R(ref __arg_1_0)) =>
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(*__self_0) == (*__arg_1_0),
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@ -800,7 +800,7 @@ impl ::core::cmp::PartialEq for Mixed {
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{
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let __self_vi = ::core::intrinsics::discriminant_value(&*self);
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let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other);
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if true && __self_vi == __arg_1_vi {
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if __self_vi == __arg_1_vi {
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match (&*self, &*other) {
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(&Mixed::R(ref __self_0), &Mixed::R(ref __arg_1_0)) =>
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(*__self_0) != (*__arg_1_0),
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@ -837,7 +837,7 @@ impl ::core::cmp::PartialOrd for Mixed {
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{
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let __self_vi = ::core::intrinsics::discriminant_value(&*self);
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let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other);
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if true && __self_vi == __arg_1_vi {
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if __self_vi == __arg_1_vi {
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match (&*self, &*other) {
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(&Mixed::R(ref __self_0), &Mixed::R(ref __arg_1_0)) =>
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match ::core::cmp::PartialOrd::partial_cmp(&(*__self_0),
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@ -880,7 +880,7 @@ impl ::core::cmp::Ord for Mixed {
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{
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let __self_vi = ::core::intrinsics::discriminant_value(&*self);
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let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other);
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if true && __self_vi == __arg_1_vi {
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if __self_vi == __arg_1_vi {
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match (&*self, &*other) {
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(&Mixed::R(ref __self_0), &Mixed::R(ref __arg_1_0)) =>
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match ::core::cmp::Ord::cmp(&(*__self_0), &(*__arg_1_0)) {
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@ -973,7 +973,7 @@ impl ::core::cmp::PartialEq for Fielded {
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{
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let __self_vi = ::core::intrinsics::discriminant_value(&*self);
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let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other);
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if true && __self_vi == __arg_1_vi {
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if __self_vi == __arg_1_vi {
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match (&*self, &*other) {
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(&Fielded::X(ref __self_0), &Fielded::X(ref __arg_1_0)) =>
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(*__self_0) == (*__arg_1_0),
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@ -991,7 +991,7 @@ impl ::core::cmp::PartialEq for Fielded {
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{
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let __self_vi = ::core::intrinsics::discriminant_value(&*self);
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let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other);
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if true && __self_vi == __arg_1_vi {
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if __self_vi == __arg_1_vi {
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match (&*self, &*other) {
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(&Fielded::X(ref __self_0), &Fielded::X(ref __arg_1_0)) =>
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(*__self_0) != (*__arg_1_0),
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@ -1029,7 +1029,7 @@ impl ::core::cmp::PartialOrd for Fielded {
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{
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let __self_vi = ::core::intrinsics::discriminant_value(&*self);
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let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other);
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if true && __self_vi == __arg_1_vi {
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if __self_vi == __arg_1_vi {
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match (&*self, &*other) {
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(&Fielded::X(ref __self_0), &Fielded::X(ref __arg_1_0)) =>
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match ::core::cmp::PartialOrd::partial_cmp(&(*__self_0),
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@ -1072,7 +1072,7 @@ impl ::core::cmp::Ord for Fielded {
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{
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let __self_vi = ::core::intrinsics::discriminant_value(&*self);
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let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other);
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if true && __self_vi == __arg_1_vi {
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if __self_vi == __arg_1_vi {
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match (&*self, &*other) {
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(&Fielded::X(ref __self_0), &Fielded::X(ref __arg_1_0)) =>
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match ::core::cmp::Ord::cmp(&(*__self_0), &(*__arg_1_0)) {
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