---

yaml
---
r: 106311
b: refs/heads/auto
c: 4112941
h: refs/heads/master
i:
  106309: 7255729
  106307: aef00c0
  106303: cfa1581
v: v3

Author: edwardw

[refs]

@@ -13,7 +13,7 @@ refs/heads/try3: 9387340aab40a73e8424c48fd42f0c521a4875c0
 refs/tags/release-0.3.1: 495bae036dfe5ec6ceafd3312b4dca48741e845b
 refs/tags/release-0.4: e828ea2080499553b97dfe33b3f4d472b4562ad7
 refs/tags/release-0.5: 7e3bcfbf21278251ee936ad53e92e9b719702d73
-refs/heads/auto: c329a17461b29da3c9f004154d32e4f153d727df
+refs/heads/auto: 4112941202d89477f1b34f559f2c16ef981e8eb6
 refs/heads/servo: af82457af293e2a842ba6b7759b70288da276167
 refs/tags/release-0.6: b4ebcfa1812664df5e142f0134a5faea3918544c
 refs/tags/0.1: b19db808c2793fe2976759b85a355c3ad8c8b336

branches/auto/src/librustc/middle/trans/_match.rs

@@ -256,43 +256,23 @@ enum Opt {
     vec_len(/* length */ uint, VecLenOpt, /*range of matches*/(uint, uint))
 }
 
+fn lit_to_expr(tcx: &ty::ctxt, a: &Lit) -> @ast::Expr {
+    match *a {
+        ExprLit(existing_a_expr) => existing_a_expr,
+        ConstLit(a_const) => const_eval::lookup_const_by_id(tcx, a_const).unwrap(),
+        UnitLikeStructLit(_) => fail!("lit_to_expr: unexpected struct lit"),
+    }
+}
+
 fn opt_eq(tcx: &ty::ctxt, a: &Opt, b: &Opt) -> bool {
     match (a, b) {
+        (&lit(UnitLikeStructLit(a)), &lit(UnitLikeStructLit(b))) => a == b,
         (&lit(a), &lit(b)) => {
-            match (a, b) {
-                (UnitLikeStructLit(a), UnitLikeStructLit(b)) => a == b,
-                _ => {
-                    let a_expr;
-                    match a {
-                        ExprLit(existing_a_expr) => a_expr = existing_a_expr,
-                            ConstLit(a_const) => {
-                                let e = const_eval::lookup_const_by_id(tcx, a_const);
-                                a_expr = e.unwrap();
-                            }
-                        UnitLikeStructLit(_) => {
-                            fail!("UnitLikeStructLit should have been handled \
-                                    above")
-                        }
-                    }
-
-                    let b_expr;
-                    match b {
-                        ExprLit(existing_b_expr) => b_expr = existing_b_expr,
-                            ConstLit(b_const) => {
-                                let e = const_eval::lookup_const_by_id(tcx, b_const);
-                                b_expr = e.unwrap();
-                            }
-                        UnitLikeStructLit(_) => {
-                            fail!("UnitLikeStructLit should have been handled \
-                                    above")
-                        }
-                    }
-
-                    match const_eval::compare_lit_exprs(tcx, a_expr, b_expr) {
-                        Some(val1) => val1 == 0,
-                        None => fail!("compare_list_exprs: type mismatch"),
-                    }
-                }
+            let a_expr = lit_to_expr(tcx, &a);
+            let b_expr = lit_to_expr(tcx, &b);
+            match const_eval::compare_lit_exprs(tcx, a_expr, b_expr) {
+                Some(val1) => val1 == 0,
+                None => fail!("compare_list_exprs: type mismatch"),
             }
         }
         (&range(a1, a2), &range(b1, b2)) => {
@@ -310,6 +290,42 @@ fn opt_eq(tcx: &ty::ctxt, a: &Opt, b: &Opt) -> bool {
     }
 }
 
+fn opt_overlap(tcx: &ty::ctxt, a: &Opt, b: &Opt) -> bool {
+    match (a, b) {
+        (&lit(a), &lit(b)) => {
+            let a_expr = lit_to_expr(tcx, &a);
+            let b_expr = lit_to_expr(tcx, &b);
+            match const_eval::compare_lit_exprs(tcx, a_expr, b_expr) {
+                Some(val1) => val1 == 0,
+                None => fail!("opt_overlap: type mismatch"),
+            }
+        }
+
+        (&range(a1, a2), &range(b1, b2)) => {
+            let m1 = const_eval::compare_lit_exprs(tcx, a1, b2);
+            let m2 = const_eval::compare_lit_exprs(tcx, b1, a2);
+            match (m1, m2) {
+                // two ranges [a1, a2] and [b1, b2] overlap iff:
+                //      a1 <= b2 && b1 <= a2
+                (Some(val1), Some(val2)) => (val1 <= 0 && val2 <= 0),
+                _ => fail!("opt_overlap: type mismatch"),
+            }
+        }
+
+        (&range(a1, a2), &lit(b)) | (&lit(b), &range(a1, a2)) => {
+            let b_expr = lit_to_expr(tcx, &b);
+            let m1 = const_eval::compare_lit_exprs(tcx, a1, b_expr);
+            let m2 = const_eval::compare_lit_exprs(tcx, a2, b_expr);
+            match (m1, m2) {
+                // b is in range [a1, a2] iff a1 <= b and b <= a2
+                (Some(val1), Some(val2)) => (val1 <= 0 && 0 <= val2),
+                _ => fail!("opt_overlap: type mismatch"),
+            }
+        }
+        _ => fail!("opt_overlap: expect lit or range")
+    }
+}
+
 pub enum opt_result<'a> {
     single_result(Result<'a>),
     lower_bound(Result<'a>),
@@ -490,7 +506,7 @@ fn assert_is_binding_or_wild(bcx: &Block, p: @ast::Pat) {
     }
 }
 
-type enter_pat<'a> = 'a |@ast::Pat| -> Option<Vec<@ast::Pat> >;
+type enter_pat<'a> = 'a |@ast::Pat| -> Option<Vec<@ast::Pat>>;
 
 fn enter_match<'r,'b>(
                bcx: &'b Block<'b>,
@@ -632,16 +648,30 @@ fn enter_opt<'r,'b>(
     let tcx = bcx.tcx();
     let dummy = @ast::Pat {id: 0, node: ast::PatWild, span: DUMMY_SP};
     let mut i = 0;
+    // By the virtue of fact that we are in `trans` already, `enter_opt` is able
+    // to prune sub-match tree aggressively based on exact equality. But when it
+    // comes to literal or range, that strategy may lead to wrong result if there
+    // are guard function or multiple patterns inside tuple; in that case, pruning
+    // based on the overlap of patterns is required.
+    //
+    // Ideally, when constructing the sub-match tree for certain arm, only those
+    // arms beneath it matter. But that isn't how algorithm works right now and
+    // all other arms are taken into consideration when computing `guarded` below.
+    // That is ok since each round of `compile_submatch` guarantees to trim one
+    // "column" of arm patterns and the algorithm will converge.
+    let guarded = m.iter().any(|x| x.data.arm.guard.is_some());
+    let multi_pats = m.len() > 0 && m[0].pats.len() > 1;
     enter_match(bcx, tcx.def_map, m, col, val, |p| {
         let answer = match p.node {
             ast::PatEnum(..) |
             ast::PatIdent(_, _, None) if pat_is_const(tcx.def_map, p) => {
                 let const_def = tcx.def_map.borrow().get_copy(&p.id);
                 let const_def_id = ast_util::def_id_of_def(const_def);
-                if opt_eq(tcx, &lit(ConstLit(const_def_id)), opt) {
-                    Some(Vec::new())
-                } else {
-                    None
+                let konst = lit(ConstLit(const_def_id));
+                match guarded || multi_pats {
+                    false if opt_eq(tcx, &konst, opt) => Some(Vec::new()),
+                    true if opt_overlap(tcx, &konst, opt) => Some(Vec::new()),
+                    _ => None,
                 }
             }
             ast::PatEnum(_, ref subpats) => {
@@ -666,10 +696,20 @@ fn enter_opt<'r,'b>(
                 }
             }
             ast::PatLit(l) => {
-                if opt_eq(tcx, &lit(ExprLit(l)), opt) {Some(Vec::new())} else {None}
+                let lit_expr = lit(ExprLit(l));
+                match guarded || multi_pats {
+                    false if opt_eq(tcx, &lit_expr, opt) => Some(Vec::new()),
+                    true if opt_overlap(tcx, &lit_expr, opt) => Some(Vec::new()),
+                    _ => None,
+                }
             }
             ast::PatRange(l1, l2) => {
-                if opt_eq(tcx, &range(l1, l2), opt) {Some(Vec::new())} else {None}
+                let rng = range(l1, l2);
+                match guarded || multi_pats {
+                    false if opt_eq(tcx, &rng, opt) => Some(Vec::new()),
+                    true if opt_overlap(tcx, &rng, opt) => Some(Vec::new()),
+                    _ => None,
+                }
             }
             ast::PatStruct(_, ref field_pats, _) => {
                 if opt_eq(tcx, &variant_opt(bcx, p.id), opt) {

branches/auto/src/libsyntax/parse/parser.rs

@@ -111,6 +111,13 @@ pub enum PathParsingMode {
     LifetimeAndTypesAndBounds,
 }
 
+/// A pair of a path segment and group of type parameter bounds. (See `ast.rs`
+/// for the definition of a path segment.)
+struct PathSegmentAndBoundSet {
+    segment: ast::PathSegment,
+    bound_set: Option<OwnedSlice<TyParamBound>>,
+}
+
 /// A path paired with optional type bounds.
 pub struct PathAndBounds {
     path: ast::Path,
@@ -1507,14 +1514,24 @@ impl<'a> Parser<'a> {
             // First, parse an identifier.
             let identifier = self.parse_ident();
 
+            // Next, parse a colon and bounded type parameters, if applicable.
+            let bound_set = if mode == LifetimeAndTypesAndBounds {
+                self.parse_optional_ty_param_bounds()
+            } else {
+                None
+            };
+
             // Parse the '::' before type parameters if it's required. If
             // it is required and wasn't present, then we're done.
             if mode == LifetimeAndTypesWithColons &&
                     !self.eat(&token::MOD_SEP) {
-                segments.push(ast::PathSegment {
-                    identifier: identifier,
-                    lifetimes: Vec::new(),
-                    types: OwnedSlice::empty(),
+                segments.push(PathSegmentAndBoundSet {
+                    segment: ast::PathSegment {
+                        identifier: identifier,
+                        lifetimes: Vec::new(),
+                        types: OwnedSlice::empty(),
+                    },
+                    bound_set: bound_set
                 });
                 break
             }
@@ -1531,10 +1548,13 @@ impl<'a> Parser<'a> {
             };
 
             // Assemble and push the result.
-            segments.push(ast::PathSegment {
-                identifier: identifier,
-                lifetimes: lifetimes,
-                types: types,
+            segments.push(PathSegmentAndBoundSet {
+                segment: ast::PathSegment {
+                    identifier: identifier,
+                    lifetimes: lifetimes,
+                    types: types,
+                },
+                bound_set: bound_set
             });
 
             // We're done if we don't see a '::', unless the mode required
@@ -1547,25 +1567,42 @@ impl<'a> Parser<'a> {
             }
         }
 
-        // Next, parse a colon and bounded type parameters, if applicable.
-        let bounds = if mode == LifetimeAndTypesAndBounds {
-            self.parse_optional_ty_param_bounds()
-        } else {
-            None
-        };
-
         // Assemble the span.
         let span = mk_sp(lo, self.last_span.hi);
 
+        // Assemble the path segments.
+        let mut path_segments = Vec::new();
+        let mut bounds = None;
+        let last_segment_index = segments.len() - 1;
+        for (i, segment_and_bounds) in segments.move_iter().enumerate() {
+            let PathSegmentAndBoundSet {
+                segment: segment,
+                bound_set: bound_set
+            } = segment_and_bounds;
+            path_segments.push(segment);
+
+            if bound_set.is_some() {
+                if i != last_segment_index {
+                    self.span_err(span,
+                                  "type parameter bounds are allowed only \
+                                   before the last segment in a path")
+                }
+
+                bounds = bound_set
+            }
+        }
+
         // Assemble the result.
-        PathAndBounds {
+        let path_and_bounds = PathAndBounds {
             path: ast::Path {
                 span: span,
                 global: is_global,
-                segments: segments,
+                segments: path_segments,
             },
             bounds: bounds,
-        }
+        };
+
+        path_and_bounds
     }
 
     /// parses 0 or 1 lifetime

branches/auto/src/libsyntax/print/pprust.rs

@@ -1526,7 +1526,7 @@ impl<'a> State<'a> {
         }
 
         let mut first = true;
-        for segment in path.segments.iter() {
+        for (i, segment) in path.segments.iter().enumerate() {
             if first {
                 first = false
             } else {
@@ -1535,6 +1535,14 @@ impl<'a> State<'a> {
 
             try!(self.print_ident(segment.identifier));
 
+            // If this is the last segment, print the bounds.
+            if i == path.segments.len() - 1 {
+                match *opt_bounds {
+                    None => {}
+                    Some(ref bounds) => try!(self.print_bounds(bounds, true)),
+                }
+            }
+
             if !segment.lifetimes.is_empty() || !segment.types.is_empty() {
                 if colons_before_params {
                     try!(word(&mut self.s, "::"))
@@ -1563,11 +1571,7 @@ impl<'a> State<'a> {
                 try!(word(&mut self.s, ">"))
             }
         }
-
-        match *opt_bounds {
-            None => Ok(()),
-            Some(ref bounds) => self.print_bounds(bounds, true),
-        }
+        Ok(())
     }
 
     fn print_path(&mut self, path: &ast::Path,

branches/auto/src/test/compile-fail/kindck-owned-trait-contains.rs

@@ -14,8 +14,8 @@ impl<A:Clone> Repeat<A> for A {
     fn get(&self) -> A { self.clone() }
 }
 
-fn repeater<A:Clone>(v: A) -> ~Repeat<A>: {
-    ~v as ~Repeat<A>: // No
+fn repeater<A:Clone>(v: A) -> ~Repeat:<A> {
+    ~v as ~Repeat:<A> // No
 }
 
 fn main() {

branches/auto/src/test/run-pass/alignment-gep-tup-like-1.rs

@@ -27,11 +27,11 @@ impl<A:Clone> Invokable<A> for Invoker<A> {
     }
 }
 
-fn f<A:Clone + 'static>(a: A, b: u16) -> ~Invokable<A>: {
+fn f<A:Clone + 'static>(a: A, b: u16) -> ~Invokable:<A> {
     ~Invoker {
         a: a,
         b: b,
-    } as ~Invokable<A>:
+    } as ~Invokable:<A>
 }
 
 pub fn main() {

branches/auto/src/test/run-pass/close-over-big-then-small-data.rs

@@ -31,11 +31,11 @@ impl<A:Clone> Invokable<A> for Invoker<A> {
     }
 }
 
-fn f<A:Clone + 'static>(a: A, b: u16) -> ~Invokable<A>: {
+fn f<A:Clone + 'static>(a: A, b: u16) -> ~Invokable:<A> {
     ~Invoker {
         a: a,
         b: b,
-    } as ~Invokable<A>:
+    } as ~Invokable:<A>
 }
 
 pub fn main() {