Remove preconditions from libraries

Closes #1805

src/comp/back/rpath.rs

@@ -40,7 +40,6 @@ fn get_sysroot_absolute_rt_lib(sess: session::session) -> fs::path {
         + filesearch::relative_target_lib_path(
             sess.opts.target_triple)
         + [os::dylib_filename("rustrt")];
-    check vec::is_not_empty(path);
     fs::connect_many(path)
 }
 
@@ -174,7 +173,6 @@ fn get_install_prefix_rpath(cwd: fs::path, target_triple: str) -> str {
 
     let path = [install_prefix]
         + filesearch::relative_target_lib_path(target_triple);
-    check vec::is_not_empty(path);
     get_absolute(cwd, fs::connect_many(path))
 }
 

src/comp/middle/last_use.rs

@@ -209,7 +209,6 @@ fn visit_block(tp: block_type, cx: ctx, visit: fn()) {
     cx.current = start_current;
     visit();
     let cx_blocks = cx.blocks;
-    check is_not_empty(cx_blocks);
     cx.blocks = tail(cx_blocks);
     let branches = if tp == func { local.exits + [cx.current] }
                    else { local.exits };

src/comp/middle/resolve.rs

@@ -289,7 +289,6 @@ fn map_crate(e: @env, c: @ast::crate) {
                 alt follow_import(*e, sc, *path, vp.span) {
                   some(imp) {
                     let glob = {def: imp, path: vp};
-                    check list::is_not_empty(sc);
                     alt list::head(sc) {
                       scope_item(i) {
                         e.mod_map.get(i.id).glob_imports += [glob];
@@ -585,7 +584,6 @@ fn visit_block_with_scope(b: ast::blk, sc: scopes, v: vt<scopes>) {
 }
 
 fn visit_decl_with_scope(d: @decl, sc: scopes, v: vt<scopes>) {
-    check list::is_not_empty(sc);
     let loc_pos = alt list::head(sc) {
       scope_block(_, _, pos) { pos }
       _ { @mutable 0u }

src/comp/middle/trans/alt.rs

@@ -278,7 +278,6 @@ fn extract_variant_args(bcx: block, pat_id: ast::node_id,
     let vdefs_tg = vdefs.enm;
     let vdefs_var = vdefs.var;
     while i < size {
-        check (valid_variant_index(i, bcx, vdefs_tg, vdefs_var));
         let r =
             // invariant needed:
             // how do we know it even makes sense to pass in ty_param_substs

src/comp/middle/trans/base.rs

@@ -355,9 +355,10 @@ fn GEP_tup_like(bcx: block, t: ty::t, base: ValueRef, ixs: [int])
 // is meaningless, as it will be cast away.
 fn GEP_enum(cx: block, llblobptr: ValueRef, enum_id: ast::def_id,
            variant_id: ast::def_id, ty_substs: [ty::t],
-           ix: uint) : valid_variant_index(ix, cx, enum_id, variant_id) ->
-   result {
+           ix: uint) -> result {
     let variant = ty::enum_variant_with_id(cx.tcx(), enum_id, variant_id);
+    assert ix < variant.args.len();
+
     // Synthesize a tuple type so that GEP_tup_like() can work its magic.
     // Separately, store the type of the element we're interested in.
 
@@ -1119,7 +1120,6 @@ fn iter_structural_ty(cx: block, av: ValueRef, t: ty::t,
             let j = 0u;
             let v_id = variant.id;
             for a: ty::arg in args {
-                check (valid_variant_index(j, cx, tid, v_id));
                 let rslt = GEP_enum(cx, a_tup, tid, v_id, tps, j);
                 let llfldp_a = rslt.val;
                 cx = rslt.bcx;
@@ -4031,7 +4031,6 @@ fn trans_enum_variant(ccx: crate_ctxt, enum_id: ast::node_id,
     let t_id = local_def(enum_id);
     let v_id = local_def(variant.node.id);
     for va: ast::variant_arg in variant.node.args {
-        check (valid_variant_index(i, bcx, t_id, v_id));
         let rslt = GEP_enum(bcx, llblobptr, t_id, v_id, ty_param_substs, i);
         bcx = rslt.bcx;
         let lldestptr = rslt.val;

src/comp/middle/trans/build.rs

@@ -529,7 +529,6 @@ fn add_span_comment(bcx: block, sp: span, text: str) {
 fn add_comment(bcx: block, text: str) {
     let ccx = bcx.ccx();
     if (!ccx.sess.opts.no_asm_comments) {
-        check str::is_not_empty("$");
         let sanitized = str::replace(text, "$", "");
         let comment_text = "; " + sanitized;
         let asm = str::as_buf(comment_text, {|c|

src/comp/middle/trans/common.rs

@@ -835,20 +835,6 @@ fn C_shape(ccx: crate_ctxt, bytes: [u8]) -> ValueRef {
     ret llvm::LLVMConstPointerCast(llglobal, T_ptr(T_i8()));
 }
 
-
-pure fn valid_variant_index(ix: uint, cx: block, enum_id: ast::def_id,
-                            variant_id: ast::def_id) -> bool {
-
-    // Handwaving: it's ok to pretend this code is referentially
-    // transparent, because the relevant parts of the type context don't
-    // change. (We're not adding new variants during trans.)
-    unchecked{
-        let variant =
-            ty::enum_variant_with_id(cx.tcx(), enum_id, variant_id);
-        ix < variant.args.len()
-    }
-}
-
 pure fn type_has_static_size(cx: crate_ctxt, t: ty::t) -> bool {
     !ty::type_has_dynamic_size(cx.tcx, t)
 }

src/comp/syntax/parse/parser.rs

@@ -888,7 +888,6 @@ fn parse_bottom_expr(p: parser) -> pexpr {
         /* Should be a predicate (pure boolean function) applied to
            arguments that are all either slot variables or literals.
            but the typechecker enforces that. */
-
         let e = parse_expr(p);
         hi = e.span.hi;
         ex = ast::expr_check(ast::checked_expr, e);

src/comp/util/filesearch.rs

@@ -89,7 +89,6 @@ fn relative_target_lib_path(target_triple: str) -> [fs::path] {
 fn make_target_lib_path(sysroot: fs::path,
                         target_triple: str) -> fs::path {
     let path = [sysroot] + relative_target_lib_path(target_triple);
-    check vec::is_not_empty(path);
     let path = fs::connect_many(path);
     ret path;
 }
@@ -112,7 +111,6 @@ fn get_sysroot(maybe_sysroot: option<fs::path>) -> fs::path {
 
 fn get_cargo_sysroot() -> result::t<fs::path, str> {
     let path = [get_default_sysroot(), libdir(), "cargo"];
-    check vec::is_not_empty(path);
     result::ok(fs::connect_many(path))
 }
 

src/libcore/str.rs

@@ -659,7 +659,8 @@ Returns:
 
 The original string with all occurances of `from` replaced with `to`
 */
-fn replace(s: str, from: str, to: str) : is_not_empty(from) -> str unsafe {
+fn replace(s: str, from: str, to: str) -> str unsafe {
+    assert is_not_empty(from);
     if len_bytes(s) == 0u {
         ret "";
     } else if starts_with(s, from) {
@@ -1922,12 +1923,10 @@ mod tests {
     #[test]
     fn test_replace() {
         let a = "a";
-        check (is_not_empty(a));
         assert (replace("", a, "b") == "");
         assert (replace("a", a, "b") == "b");
         assert (replace("ab", a, "b") == "bb");
         let test = "test";
-        check (is_not_empty(test));
         assert (replace(" test test ", test, "toast") == " toast toast ");
         assert (replace(" test test ", test, "") == "   ");
     }
@@ -1939,7 +1938,6 @@ mod tests {
 
         let a = "ประเ";
         let A = "دولة الكويتทศไทย中华";
-        check is_not_empty(a);
         assert (replace(data, a, repl) ==  A);
     }
 
@@ -1950,7 +1948,6 @@ mod tests {
 
         let b = "ะเ";
         let B = "ปรدولة الكويتทศไทย中华";
-        check is_not_empty(b);
         assert (replace(data, b,   repl) ==  B);
     }
 
@@ -1961,7 +1958,6 @@ mod tests {
 
         let c = "中华";
         let C = "ประเทศไทยدولة الكويت";
-        check is_not_empty(c);
         assert (replace(data, c, repl) ==  C);
     }
 
@@ -1971,7 +1967,6 @@ mod tests {
         let repl = "دولة الكويت";
 
         let d = "ไท华";
-        check is_not_empty(d);
         assert (replace(data, d, repl) == data);
     }
 

src/libcore/vec.rs

@@ -180,7 +180,7 @@ Returns the first element of a vector
 Predicates:
 <is_not_empty> (v)
 */
-pure fn head<T: copy>(v: [const T]) : is_not_empty(v) -> T { ret v[0]; }
+pure fn head<T: copy>(v: [const T]) -> T { v[0] }
 
 /*
 Function: tail
@@ -240,9 +240,7 @@ Returns the last element of a non-empty vector `v`
 Predicates:
 <is_not_empty> (v)
 */
-pure fn last_total<T: copy>(v: [const T]) : is_not_empty(v) -> T {
-    ret v[len(v) - 1u];
-}
+pure fn last_total<T: copy>(v: [const T]) -> T { v[len(v) - 1u] }
 
 /*
 Function: slice
@@ -886,10 +884,10 @@ Preconditions:
 
 <same_length> (v, u)
 */
-fn zip<T: copy, U: copy>(v: [T], u: [U]) : same_length(v, u) -> [(T, U)] {
+fn zip<T: copy, U: copy>(v: [T], u: [U]) -> [(T, U)] {
     let zipped = [];
     let sz = len(v), i = 0u;
-    assert (sz == len(u));
+    assert sz == len(u);
     while i < sz { zipped += [(v[i], u[i])]; i += 1u; }
     ret zipped;
 }
@@ -940,7 +938,8 @@ Function: enum_chars
 
 Returns a vector containing a range of chars
 */
-fn enum_chars(start: u8, end: u8) : ::u8::le(start, end) -> [char] {
+fn enum_chars(start: u8, end: u8) -> [char] {
+    assert start < end;
     let i = start;
     let r = [];
     while i <= end { r += [i as char]; i += 1u as u8; }
@@ -953,7 +952,8 @@ Function: enum_uints
 
 Returns a vector containing a range of uints
 */
-fn enum_uints(start: uint, end: uint) : uint::le(start, end) -> [uint] {
+fn enum_uints(start: uint, end: uint) -> [uint] {
+    assert start < end;
     let i = start;
     let r = [];
     while i <= end { r += [i]; i += 1u; }
@@ -1329,18 +1329,15 @@ mod tests {
     #[test]
     fn test_head() {
         let a = [11, 12];
-        check (is_not_empty(a));
         assert (head(a) == 11);
     }
 
     #[test]
     fn test_tail() {
         let a = [11];
-        check (is_not_empty(a));
         assert (tail(a) == []);
 
         a = [11, 12];
-        check (is_not_empty(a));
         assert (tail(a) == [12]);
     }
 
@@ -1667,7 +1664,6 @@ mod tests {
         let v1 = [1, 2, 3];
         let v2 = [4, 5, 6];
 
-        check (same_length(v1, v2)); // Silly, but what else can we do?
         let z1 = zip(v1, v2);
 
         assert ((1, 4) == z1[0]);

src/libstd/fs.rs

@@ -107,12 +107,11 @@ Connects a vector of path segments into a single path.
 
 Inserts path separators as needed.
 */
-fn connect_many(paths: [path]) : vec::is_not_empty(paths) -> path {
+fn connect_many(paths: [path]) -> path {
     ret if vec::len(paths) == 1u {
         paths[0]
     } else {
         let rest = vec::slice(paths, 1u, vec::len(paths));
-        check vec::is_not_empty(rest);
         connect(paths[0], connect_many(rest))
     }
 }

src/libstd/list.rs

@@ -140,11 +140,8 @@ Function: head
 
 Returns the first element of a list
 */
-pure fn head<T: copy>(ls: list<T>) : is_not_empty(ls) -> T {
-    alt ls {
-        cons(hd, _) { ret hd; }
-        nil { fail "list empty" }
-    }
+pure fn head<T: copy>(ls: list<T>) -> T {
+    alt check ls { cons(hd, _) { hd } }
 }
 
 /*
@@ -205,15 +202,12 @@ mod tests {
     fn test_from_vec() {
         let l = from_vec([0, 1, 2]);
 
-        check is_not_empty(l);
         assert (head(l) == 0);
 
         let tail_l = tail(l);
-        check is_not_empty(tail_l);
         assert (head(tail_l) == 1);
 
         let tail_tail_l = tail(tail_l);
-        check is_not_empty(tail_tail_l);
         assert (head(tail_tail_l) == 2);
     }
 
@@ -227,15 +221,12 @@ mod tests {
     fn test_from_vec_mut() {
         let l = from_vec([mutable 0, 1, 2]);
 
-        check is_not_empty(l);
         assert (head(l) == 0);
 
         let tail_l = tail(l);
-        check is_not_empty(tail_l);
         assert (head(tail_l) == 1);
 
         let tail_tail_l = tail(tail_l);
-        check is_not_empty(tail_tail_l);
         assert (head(tail_tail_l) == 2);
     }
 

src/libstd/sort.rs

@@ -252,8 +252,6 @@ mod test_qsort {
 
         let immut_names = vec::from_mut(names);
 
-        // Silly, but what else can we do?
-        check (vec::same_length(expected, immut_names));
         let pairs = vec::zip(expected, immut_names);
         for (a, b) in pairs { #debug("%d %d", a, b); assert (a == b); }
     }

src/libstd/test.rs

@@ -47,7 +47,6 @@ type test_desc = {
 // The default console test runner. It accepts the command line
 // arguments and a vector of test_descs (generated at compile time).
 fn test_main(args: [str], tests: [test_desc]) {
-    check (vec::is_not_empty(args));
     let opts =
         alt parse_opts(args) {
           either::left(o) { o }
@@ -61,8 +60,7 @@ type test_opts = {filter: option<str>, run_ignored: bool};
 type opt_res = either::t<test_opts, str>;
 
 // Parses command line arguments into test options
-fn parse_opts(args: [str]) : vec::is_not_empty(args) -> opt_res {
-
+fn parse_opts(args: [str]) -> opt_res {
     let args_ = vec::tail(args);
     let opts = [getopts::optflag("ignored")];
     let match =
@@ -407,7 +405,6 @@ mod tests {
     #[test]
     fn first_free_arg_should_be_a_filter() {
         let args = ["progname", "filter"];
-        check (vec::is_not_empty(args));
         let opts = alt parse_opts(args) { either::left(o) { o }
           _ { fail "Malformed arg in first_free_arg_should_be_a_filter"; } };
         assert (str::eq("filter", option::get(opts.filter)));
@@ -416,7 +413,6 @@ mod tests {
     #[test]
     fn parse_ignored_flag() {
         let args = ["progname", "filter", "--ignored"];
-        check (vec::is_not_empty(args));
         let opts = alt parse_opts(args) { either::left(o) { o }
           _ { fail "Malformed arg in parse_ignored_flag"; } };
         assert (opts.run_ignored);
@@ -469,12 +465,10 @@ mod tests {
          "test::ignored_tests_result_in_ignored", "test::parse_ignored_flag",
          "test::sort_tests"];
 
-    check (vec::same_length(expected, filtered));
     let pairs = vec::zip(expected, filtered);
 
-
     for (a, b) in pairs { assert (a == b.name); }
-    }
+}
 }
 
 

src/test/compile-fail/zip-missing-check.rs

@@ -1,17 +0,0 @@
-// error-pattern:Unsatisfied precondition constraint (for example, same_length
-use std;
-import uint;
-import u8;
-import vec::*;
-
-fn main() {
-    let a = 'a' as u8, j = 'j' as u8, k = 1u, l = 10u;
-    // Silly, but necessary
-    check (u8::le(a, j));
-    check (uint::le(k, l));
-    let chars = enum_chars(a, j);
-    let ints = enum_uints(k, l);
-
-    let ps = zip(chars, ints);
-    fail "the impossible happened";
-}