librustc: Remove unique vector patterns from the language.

Preparatory work for removing unique vectors from the language, which is
itself preparatory work for dynamically sized types.

Author: pcwalton

src/libextra/test.rs

@@ -315,12 +315,15 @@ pub fn opt_shard(maybestr: Option<~str>) -> Option<(uint,uint)> {
     match maybestr {
         None => None,
         Some(s) => {
-            match s.split('.').to_owned_vec() {
-                [a, b] => match (from_str::<uint>(a), from_str::<uint>(b)) {
-                    (Some(a), Some(b)) => Some((a,b)),
+            let vector = s.split('.').to_owned_vec();
+            if vector.len() == 2 {
+                match (from_str::<uint>(vector[0]),
+                       from_str::<uint>(vector[1])) {
+                    (Some(a), Some(b)) => Some((a, b)),
                     _ => None
-                },
-                _ => None
+                }
+            } else {
+                None
             }
         }
     }

src/libnative/io/timer_other.rs

@@ -130,27 +130,25 @@ fn helper(input: libc::c_int, messages: Port<Req>) {
     }
 
     'outer: loop {
-        let timeout = match active {
+        let timeout = if active.len() == 0 {
             // Empty array? no timeout (wait forever for the next request)
-            [] => ptr::null(),
-
-            [~Inner { target, .. }, ..] => {
-                let now = now();
-                // If this request has already expired, then signal it and go
-                // through another iteration
-                if target <= now {
-                    signal(&mut active, &mut dead);
-                    continue;
-                }
-
-                // The actual timeout listed in the requests array is an
-                // absolute date, so here we translate the absolute time to a
-                // relative time.
-                let tm = target - now;
-                timeout.tv_sec = (tm / 1000) as libc::time_t;
-                timeout.tv_usec = ((tm % 1000) * 1000) as libc::suseconds_t;
-                &timeout as *libc::timeval
+            ptr::null()
+        } else {
+            let now = now();
+            // If this request has already expired, then signal it and go
+            // through another iteration
+            if active[0].target <= now {
+                signal(&mut active, &mut dead);
+                continue;
             }
+
+            // The actual timeout listed in the requests array is an
+            // absolute date, so here we translate the absolute time to a
+            // relative time.
+            let tm = active[0].target - now;
+            timeout.tv_sec = (tm / 1000) as libc::time_t;
+            timeout.tv_usec = ((tm % 1000) * 1000) as libc::suseconds_t;
+            &timeout as *libc::timeval
         };
 
         imp::fd_set(&mut set, input);

src/libnum/bigint.rs

@@ -495,24 +495,23 @@ impl ToPrimitive for BigUint {
     #[cfg(target_word_size = "32")]
     #[inline]
     fn to_u64(&self) -> Option<u64> {
-        match self.data {
-            [] => {
-                Some(0)
+        match self.data.len() {
+            0 => Some(0),
+            1 => Some(self.data[0] as u64),
+            2 => {
+                Some(BigDigit::to_uint(self.data[1], self.data[0]) as u64)
             }
-            [n0] => {
-                Some(n0 as u64)
-            }
-            [n0, n1] => {
-                Some(BigDigit::to_uint(n1, n0) as u64)
-            }
-            [n0, n1, n2] => {
-                let n_lo = BigDigit::to_uint(n1, n0) as u64;
-                let n_hi = n2 as u64;
+            3 => {
+                let n_lo = BigDigit::to_uint(self.data[1], self.data[0]) as
+                    u64;
+                let n_hi = self.data[2] as u64;
                 Some((n_hi << 32) + n_lo)
             }
-            [n0, n1, n2, n3] => {
-                let n_lo = BigDigit::to_uint(n1, n0) as u64;
-                let n_hi = BigDigit::to_uint(n3, n2) as u64;
+            4 => {
+                let n_lo = BigDigit::to_uint(self.data[1], self.data[0])
+                    as u64;
+                let n_hi = BigDigit::to_uint(self.data[3], self.data[2])
+                    as u64;
                 Some((n_hi << 32) + n_lo)
             }
             _ => None
@@ -522,16 +521,10 @@ impl ToPrimitive for BigUint {
     #[cfg(target_word_size = "64")]
     #[inline]
     fn to_u64(&self) -> Option<u64> {
-        match self.data {
-            [] => {
-                Some(0)
-            }
-            [n0] => {
-                Some(n0 as u64)
-            }
-            [n0, n1] => {
-                Some(BigDigit::to_uint(n1, n0) as u64)
-            }
+        match self.data.len() {
+            0 => Some(0),
+            1 => Some(self.data[0] as u64),
+            2 => Some(BigDigit::to_uint(self.data[1], self.data[0]) as u64),
             _ => None
         }
     }

src/librustc/middle/lint.rs

@@ -1213,15 +1213,13 @@ fn check_unused_mut_pat(cx: &Context, p: &ast::Pat) {
         ast::PatIdent(ast::BindByValue(ast::MutMutable),
                       ref path, _) if pat_util::pat_is_binding(cx.tcx.def_map, p)=> {
             // `let mut _a = 1;` doesn't need a warning.
-            let initial_underscore = match path.segments {
-                [ast::PathSegment { identifier: id, .. }] => {
-                    token::get_ident(id).get().starts_with("_")
-                }
-                _ => {
-                    cx.tcx.sess.span_bug(p.span,
-                                         "mutable binding that doesn't \
-                                         consist of exactly one segment");
-                }
+            let initial_underscore = if path.segments.len() == 1 {
+                token::get_ident(path.segments[0].identifier).get()
+                                                             .starts_with("_")
+            } else {
+                cx.tcx.sess.span_bug(p.span,
+                                     "mutable binding that doesn't consist \
+                                      of exactly one segment")
             };
 
             let used_mut_nodes = cx.tcx.used_mut_nodes.borrow();

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

@@ -603,7 +603,17 @@ pub fn check_pat(pcx: &pat_ctxt, pat: &ast::Pat, expected: ty::t) {
           ty::ty_vec(mt, vstore) => {
             let region_var = match vstore {
                 ty::vstore_slice(r) => r,
-                ty::vstore_uniq | ty::vstore_fixed(_) => {
+                ty::vstore_uniq => {
+                    fcx.type_error_message(pat.span,
+                                           |_| {
+                                            ~"unique vector patterns are no \
+                                              longer supported"
+                                           },
+                                           expected,
+                                           None);
+                    default_region_var
+                }
+                ty::vstore_fixed(_) => {
                     default_region_var
                 }
             };

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

@@ -3894,8 +3894,11 @@ pub fn ast_expr_vstore_to_vstore(fcx: @FnCtxt,
         ast::ExprVstoreUniq => ty::vstore_uniq,
         ast::ExprVstoreSlice | ast::ExprVstoreMutSlice => {
             match e.node {
-                ast::ExprLit(..) |
-                ast::ExprVec([], _) => {
+                ast::ExprLit(..) => {
+                    // string literals and *empty slices* live in static memory
+                    ty::vstore_slice(ty::ReStatic)
+                }
+                ast::ExprVec(ref elements, _) if elements.len() == 0 => {
                     // string literals and *empty slices* live in static memory
                     ty::vstore_slice(ty::ReStatic)
                 }

src/librustdoc/passes.rs

@@ -311,20 +311,19 @@ pub fn unindent(s: &str) -> ~str {
         }
     });
 
-    match lines {
-        [head, .. tail] => {
-            let mut unindented = ~[ head.trim() ];
-            unindented.push_all(tail.map(|&line| {
-                if line.is_whitespace() {
-                    line
-                } else {
-                    assert!(line.len() >= min_indent);
-                    line.slice_from(min_indent)
-                }
-            }));
-            unindented.connect("\n")
-        }
-        [] => s.to_owned()
+    if lines.len() >= 1 {
+        let mut unindented = ~[ lines[0].trim() ];
+        unindented.push_all(lines.tail().map(|&line| {
+            if line.is_whitespace() {
+                line
+            } else {
+                assert!(line.len() >= min_indent);
+                line.slice_from(min_indent)
+            }
+        }));
+        unindented.connect("\n")
+    } else {
+        s.to_owned()
     }
 }
 

src/libsyntax/ext/deriving/clone.rs

@@ -97,30 +97,27 @@ fn cs_clone(
                                                                  name))
     }
 
-    match *all_fields {
-        [FieldInfo { name: None, .. }, ..] => {
-            // enum-like
-            let subcalls = all_fields.map(subcall);
-            cx.expr_call_ident(trait_span, ctor_ident, subcalls)
-        },
-        _ => {
-            // struct-like
-            let fields = all_fields.map(|field| {
-                let ident = match field.name {
-                    Some(i) => i,
-                    None => cx.span_bug(trait_span,
-                                        format!("unnamed field in normal struct in `deriving({})`",
-                                                name))
-                };
-                cx.field_imm(field.span, ident, subcall(field))
-            });
+    if all_fields.len() >= 1 && all_fields[0].name.is_none() {
+        // enum-like
+        let subcalls = all_fields.map(subcall);
+        cx.expr_call_ident(trait_span, ctor_ident, subcalls)
+    } else {
+        // struct-like
+        let fields = all_fields.map(|field| {
+            let ident = match field.name {
+                Some(i) => i,
+                None => cx.span_bug(trait_span,
+                                    format!("unnamed field in normal struct in `deriving({})`",
+                                            name))
+            };
+            cx.field_imm(field.span, ident, subcall(field))
+        });
 
-            if fields.is_empty() {
-                // no fields, so construct like `None`
-                cx.expr_ident(trait_span, ctor_ident)
-            } else {
-                cx.expr_struct_ident(trait_span, ctor_ident, fields)
-            }
+        if fields.is_empty() {
+            // no fields, so construct like `None`
+            cx.expr_ident(trait_span, ctor_ident)
+        } else {
+            cx.expr_struct_ident(trait_span, ctor_ident, fields)
         }
     }
 }

src/libsyntax/ext/deriving/generic.rs

@@ -663,25 +663,26 @@ impl<'a> MethodDef<'a> {
         }
 
         // transpose raw_fields
-        let fields = match raw_fields {
-            [ref self_arg, .. rest] => {
-                self_arg.iter().enumerate().map(|(i, &(span, opt_id, field))| {
-                    let other_fields = rest.map(|l| {
-                        match &l[i] {
-                            &(_, _, ex) => ex
-                        }
-                    });
-                    FieldInfo {
-                        span: span,
-                        name: opt_id,
-                        self_: field,
-                        other: other_fields
+        let fields = if raw_fields.len() > 0 {
+            raw_fields[0].iter()
+                         .enumerate()
+                         .map(|(i, &(span, opt_id, field))| {
+                let other_fields = raw_fields.tail().map(|l| {
+                    match &l[i] {
+                        &(_, _, ex) => ex
                     }
-                }).collect()
-            }
-            [] => { cx.span_bug(trait_.span,
-                                "no self arguments to non-static method \
-                                in generic `deriving`") }
+                });
+                FieldInfo {
+                    span: span,
+                    name: opt_id,
+                    self_: field,
+                    other: other_fields
+                }
+            }).collect()
+        } else {
+            cx.span_bug(trait_.span,
+                        "no self arguments to non-static method in generic \
+                         `deriving`")
         };
 
         // body of the inner most destructuring match

src/libsyntax/ext/deriving/mod.rs

@@ -54,7 +54,10 @@ pub fn expand_meta_deriving(cx: &mut ExtCtxt,
         MetaNameValue(_, ref l) => {
             cx.span_err(l.span, "unexpected value in `deriving`");
         }
-        MetaWord(_) | MetaList(_, []) => {
+        MetaWord(_) => {
+            cx.span_warn(mitem.span, "empty trait list in `deriving`");
+        }
+        MetaList(_, ref titems) if titems.len() == 0 => {
             cx.span_warn(mitem.span, "empty trait list in `deriving`");
         }
         MetaList(_, ref titems) => {

src/libsyntax/ext/deriving/show.rs

@@ -74,7 +74,8 @@ fn show_substructure(cx: &mut ExtCtxt, span: Span,
     // Getting harder... making the format string:
     match *substr.fields {
         // unit struct/nullary variant: no work necessary!
-        Struct([]) | EnumMatching(_, _, []) => {}
+        Struct(ref fields) if fields.len() == 0 => {}
+        EnumMatching(_, _, ref fields) if fields.len() == 0 => {}
 
         Struct(ref fields) | EnumMatching(_, _, ref fields) => {
             if fields[0].name.is_none() {

src/libsyntax/ext/env.rs

@@ -40,7 +40,7 @@ pub fn expand_option_env(cx: &mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
 pub fn expand_env(cx: &mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
     -> base::MacResult {
     let exprs = match get_exprs_from_tts(cx, sp, tts) {
-        Some([]) => {
+        Some(ref exprs) if exprs.len() == 0 => {
             cx.span_err(sp, "env! takes 1 or 2 arguments");
             return MacResult::dummy_expr(sp);
         }

src/libsyntax/ext/expand.rs

@@ -647,14 +647,10 @@ impl Visitor<()> for NewNameFinderContext {
                     &ast::Path {
                         global: false,
                         span: _,
-                        segments: [
-                            ast::PathSegment {
-                                identifier: id,
-                                lifetimes: _,
-                                types: _
-                            }
-                        ]
-                    } => self.ident_accumulator.push(id),
+                        segments: ref segments
+                    } if segments.len() == 1 => {
+                        self.ident_accumulator.push(segments[0].identifier)
+                    }
                     // I believe these must be enums...
                     _ => ()
                 }
@@ -1187,7 +1183,12 @@ foo_module!()
         let bindings = name_finder.ident_accumulator;
 
         let cxbinds: ~[&ast::Ident] =
-            bindings.iter().filter(|b| "xx" == token::get_ident(**b).get()).collect();
+            bindings.iter().filter(|b| {
+                let ident = token::get_ident(**b);
+                let string = ident.get();
+                "xx" == string
+            }).collect();
+        let cxbinds: &[&ast::Ident] = cxbinds;
         let cxbind = match cxbinds {
             [b] => b,
             _ => fail!("expected just one binding for ext_cx")