Improve code reuse in check_match::specialize()
This commit is contained in:
Jakub Wieczorek
parent
b981add9ee
commit
19e10e3a81
@ -20,7 +20,7 @@ use util::ppaux::ty_to_str;
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use std::cmp;
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use std::iter;
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use syntax::ast::*;
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use syntax::ast_util::{unguarded_pat, walk_pat};
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use syntax::ast_util::{is_unguarded, walk_pat};
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use syntax::codemap::{DUMMY_SP, Span};
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use syntax::parse::token;
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use syntax::visit;
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@ -79,26 +79,13 @@ fn check_expr(cx: &mut MatchCheckCtxt, ex: &Expr) {
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// If the type *is* empty, it's vacuously exhaustive
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return;
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}
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match ty::get(pat_ty).sty {
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ty_enum(did, _) => {
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if (*enum_variants(cx.tcx, did)).is_empty() &&
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(*arms).is_empty() {
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return;
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}
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}
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_ => { /* We assume only enum types can be uninhabited */ }
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}
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let pats: Vec<@Pat> = arms.iter()
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.filter_map(unguarded_pat)
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.flat_map(|pats| pats.move_iter())
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.collect();
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if pats.is_empty() {
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cx.tcx.sess.span_err(ex.span, "non-exhaustive patterns");
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} else {
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check_exhaustive(cx, ex.span, pats);
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}
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let m: matrix = arms
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.iter()
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.filter(|&arm| is_unguarded(arm))
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.flat_map(|arm| arm.pats.iter())
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.map(|pat| vec!(pat.clone()))
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.collect();
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check_exhaustive(cx, ex.span, &m);
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}
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_ => ()
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}
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@ -152,9 +139,8 @@ fn raw_pat(p: @Pat) -> @Pat {
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}
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}
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fn check_exhaustive(cx: &MatchCheckCtxt, sp: Span, pats: Vec<@Pat> ) {
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assert!((!pats.is_empty()));
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let ext = match is_useful(cx, &pats.iter().map(|p| vec!(*p)).collect(), [wild()]) {
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fn check_exhaustive(cx: &MatchCheckCtxt, sp: Span, m: &matrix) {
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let ext = match is_useful(cx, m, [wild()]) {
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not_useful => {
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// This is good, wildcard pattern isn't reachable
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return;
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@ -587,23 +573,20 @@ fn specialize(cx: &MatchCheckCtxt,
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arity: uint,
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left_ty: ty::t)
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-> Option<Vec<@Pat> > {
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// Sad, but I can't get rid of this easily
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let r0 = (*raw_pat(r[0])).clone();
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match r0 {
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Pat{id: pat_id, node: n, span: pat_span} =>
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match n {
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PatWild => {
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Some(Vec::from_elem(arity, wild()).append(r.tail()))
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let &Pat{id: ref pat_id, node: ref n, span: ref pat_span} = &(*raw_pat(r[0]));
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let head: Option<Vec<@Pat>> = match n {
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&PatWild => {
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Some(Vec::from_elem(arity, wild()))
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}
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PatWildMulti => {
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Some(Vec::from_elem(arity, wild_multi()).append(r.tail()))
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&PatWildMulti => {
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Some(Vec::from_elem(arity, wild_multi()))
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}
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PatIdent(_, _, _) => {
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let opt_def = cx.tcx.def_map.borrow().find_copy(&pat_id);
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&PatIdent(_, _, _) => {
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let opt_def = cx.tcx.def_map.borrow().find_copy(pat_id);
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match opt_def {
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Some(DefVariant(_, id, _)) => {
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if variant(id) == *ctor_id {
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Some(Vec::from_slice(r.tail()))
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Some(vec!())
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} else {
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None
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}
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@ -617,7 +600,7 @@ fn specialize(cx: &MatchCheckCtxt,
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match compare_const_vals(&e_v, v) {
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Some(val1) => (val1 == 0),
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None => {
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cx.tcx.sess.span_err(pat_span,
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cx.tcx.sess.span_err(*pat_span,
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"mismatched types between arms");
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false
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}
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@ -631,7 +614,7 @@ fn specialize(cx: &MatchCheckCtxt,
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(val1 >= 0 && val2 <= 0)
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}
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_ => {
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cx.tcx.sess.span_err(pat_span,
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cx.tcx.sess.span_err(*pat_span,
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"mismatched types between ranges");
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false
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}
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@ -641,18 +624,18 @@ fn specialize(cx: &MatchCheckCtxt,
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_ => fail!("type error")
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};
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if match_ {
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Some(Vec::from_slice(r.tail()))
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Some(vec!())
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} else {
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None
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}
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}
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_ => {
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Some(Vec::from_elem(arity, wild()).append(r.tail()))
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Some(Vec::from_elem(arity, wild()))
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}
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}
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}
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PatEnum(_, args) => {
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let def = cx.tcx.def_map.borrow().get_copy(&pat_id);
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&PatEnum(_, ref args) => {
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let def = cx.tcx.def_map.borrow().get_copy(pat_id);
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match def {
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DefStatic(did, _) => {
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let const_expr =
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@ -663,7 +646,7 @@ fn specialize(cx: &MatchCheckCtxt,
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match compare_const_vals(&e_v, v) {
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Some(val1) => (val1 == 0),
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None => {
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cx.tcx.sess.span_err(pat_span,
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cx.tcx.sess.span_err(*pat_span,
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"mismatched types between arms");
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false
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}
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@ -674,7 +657,7 @@ fn specialize(cx: &MatchCheckCtxt,
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match (m1, m2) {
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(Some(val1), Some(val2)) => (val1 >= 0 && val2 <= 0),
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_ => {
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cx.tcx.sess.span_err(pat_span,
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cx.tcx.sess.span_err(*pat_span,
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"mismatched types between ranges");
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false
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}
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@ -684,97 +667,72 @@ fn specialize(cx: &MatchCheckCtxt,
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_ => fail!("type error")
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};
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if match_ {
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Some(Vec::from_slice(r.tail()))
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Some(vec!())
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} else {
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None
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}
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}
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DefVariant(_, id, _) if variant(id) == *ctor_id => {
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let args = match args {
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Some(args) => args.iter().map(|x| *x).collect(),
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None => Vec::from_elem(arity, wild())
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};
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Some(args.append(r.tail()))
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}
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DefVariant(_, _, _) => None,
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DefFn(..) |
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DefStruct(..) => {
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let new_args;
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match args {
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Some(args) => {
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new_args = args.iter().map(|x| *x).collect()
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}
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None => new_args = Vec::from_elem(arity, wild())
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}
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Some(new_args.append(r.tail()))
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DefVariant(_, id, _) if variant(id) != *ctor_id => None,
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DefVariant(..) | DefFn(..) | DefStruct(..) => {
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Some(match args {
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&Some(ref args) => args.clone(),
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&None => Vec::from_elem(arity, wild())
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})
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}
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_ => None
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}
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}
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PatStruct(_, ref pattern_fields, _) => {
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&PatStruct(_, ref pattern_fields, _) => {
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// Is this a struct or an enum variant?
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let def = cx.tcx.def_map.borrow().get_copy(&pat_id);
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match def {
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let def = cx.tcx.def_map.borrow().get_copy(pat_id);
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let class_id = match def {
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DefVariant(_, variant_id, _) => {
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if variant(variant_id) == *ctor_id {
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let struct_fields = ty::lookup_struct_fields(cx.tcx, variant_id);
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let args = struct_fields.iter().map(|sf| {
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match pattern_fields.iter().find(|f| f.ident.name == sf.name) {
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Some(f) => f.pat,
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_ => wild()
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}
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}).collect::<Vec<_>>();
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Some(args.append(r.tail()))
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} else {
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None
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}
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if variant(variant_id) == *ctor_id {
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Some(variant_id)
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} else {
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None
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}
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}
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_ => {
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// Grab the class data that we care about.
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let class_fields;
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let class_id;
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match ty::get(left_ty).sty {
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ty::ty_struct(cid, _) => {
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class_id = cid;
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class_fields =
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ty::lookup_struct_fields(cx.tcx,
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class_id);
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}
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ty::ty_struct(cid, _) => Some(cid),
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_ => {
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cx.tcx.sess.span_bug(
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pat_span,
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*pat_span,
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format!("struct pattern resolved to {}, \
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not a struct",
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ty_to_str(cx.tcx,
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left_ty)).as_slice());
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}
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}
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let args = class_fields.iter().map(|class_field| {
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match pattern_fields.iter().find(|f|
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f.ident.name == class_field.name) {
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Some(f) => f.pat,
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_ => wild()
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}
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}).collect::<Vec<_>>();
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Some(args.append(r.tail()))
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}
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}
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};
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class_id.map(|variant_id| {
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let struct_fields = ty::lookup_struct_fields(cx.tcx, variant_id);
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let args = struct_fields.iter().map(|sf| {
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match pattern_fields.iter().find(|f| f.ident.name == sf.name) {
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Some(f) => f.pat,
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_ => wild()
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}
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}).collect();
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args
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})
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}
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PatTup(args) => {
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Some(args.iter().map(|x| *x).collect::<Vec<_>>().append(r.tail()))
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&PatTup(ref args) => {
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Some(args.iter().map(|x| *x).collect())
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}
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PatBox(a) | PatRegion(a) => {
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Some((vec!(a)).append(r.tail()))
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&PatBox(ref inner) | &PatRegion(ref inner) => {
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Some(vec!(inner.clone()))
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}
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PatLit(expr) => {
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let e_v = eval_const_expr(cx.tcx, expr);
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&PatLit(ref expr) => {
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let e_v = eval_const_expr(cx.tcx, *expr);
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let match_ = match *ctor_id {
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val(ref v) => {
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match compare_const_vals(&e_v, v) {
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Some(val1) => val1 == 0,
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None => {
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cx.tcx.sess.span_err(pat_span,
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cx.tcx.sess.span_err(*pat_span,
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"mismatched types between arms");
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false
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}
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@ -786,7 +744,7 @@ fn specialize(cx: &MatchCheckCtxt,
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match (m1, m2) {
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(Some(val1), Some(val2)) => (val1 >= 0 && val2 <= 0),
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_ => {
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cx.tcx.sess.span_err(pat_span,
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cx.tcx.sess.span_err(*pat_span,
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"mismatched types between ranges");
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false
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}
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@ -796,52 +754,49 @@ fn specialize(cx: &MatchCheckCtxt,
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_ => fail!("type error")
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};
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if match_ {
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Some(Vec::from_slice(r.tail()))
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Some(vec!())
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} else {
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None
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}
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}
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PatRange(lo, hi) => {
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&PatRange(lo, hi) => {
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let (c_lo, c_hi) = match *ctor_id {
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val(ref v) => ((*v).clone(), (*v).clone()),
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range(ref lo, ref hi) => ((*lo).clone(), (*hi).clone()),
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single => return Some(Vec::from_slice(r.tail())),
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val(ref v) => (v, v),
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range(ref lo, ref hi) => (lo, hi),
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single => return Some(vec!()),
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_ => fail!("type error")
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};
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let v_lo = eval_const_expr(cx.tcx, lo);
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let v_hi = eval_const_expr(cx.tcx, hi);
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let m1 = compare_const_vals(&c_lo, &v_lo);
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let m2 = compare_const_vals(&c_hi, &v_hi);
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let m1 = compare_const_vals(c_lo, &v_lo);
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let m2 = compare_const_vals(c_hi, &v_hi);
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match (m1, m2) {
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(Some(val1), Some(val2)) if val1 >= 0 && val2 <= 0 => {
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Some(Vec::from_slice(r.tail()))
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Some(vec!())
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},
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(Some(_), Some(_)) => None,
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_ => {
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cx.tcx.sess.span_err(pat_span,
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cx.tcx.sess.span_err(*pat_span,
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"mismatched types between ranges");
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None
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}
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}
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}
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PatVec(before, slice, after) => {
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&PatVec(ref before, ref slice, ref after) => {
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match *ctor_id {
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vec(_) => {
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let num_elements = before.len() + after.len();
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if num_elements < arity && slice.is_some() {
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let mut result = Vec::new();
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let wilds = Vec::from_elem(arity - num_elements, wild());
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result.push_all_move(before);
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result.push_all_move(wilds);
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result.push_all_move(after);
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result.push_all(r.tail());
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result.push_all(before.as_slice());
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result.grow_fn(arity - num_elements, |_| wild());
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result.push_all(after.as_slice());
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Some(result)
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} else if num_elements == arity {
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let mut result = Vec::new();
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result.push_all_move(before);
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result.push_all_move(after);
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result.push_all(r.tail());
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result.push_all(before.as_slice());
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result.push_all(after.as_slice());
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Some(result)
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} else {
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None
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@ -850,12 +805,12 @@ fn specialize(cx: &MatchCheckCtxt,
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_ => None
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}
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}
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PatMac(_) => {
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cx.tcx.sess.span_err(pat_span, "unexpanded macro");
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&PatMac(_) => {
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cx.tcx.sess.span_err(*pat_span, "unexpanded macro");
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None
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}
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}
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}
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};
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head.map(|head| head.append(r.tail()))
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}
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fn default(cx: &MatchCheckCtxt, r: &[@Pat]) -> Option<Vec<@Pat> > {
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