Do not consider ty_bot to be a "resolved type".

Fixes #2149. Fixes #2150. Fixes #2151.

Author: nikomatsakis

src/rustc/middle/typeck.rs

@@ -232,8 +232,10 @@ fn instantiate_path(fcx: @fn_ctxt, pth: @ast::path,
 // Type tests
 fn structurally_resolved_type(fcx: @fn_ctxt, sp: span, tp: ty::t) -> ty::t {
     alt infer::resolve_type_structure(fcx.infcx, tp) {
-      result::ok(typ_s) { ret typ_s; }
-      result::err(_) {
+      // note: the bot type doesn't count as resolved; it's what we use when
+      // there is no information about a variable.
+      result::ok(t_s) if !ty::type_is_bot(t_s) { ret t_s; }
+      _ {
         fcx.ccx.tcx.sess.span_fatal
             (sp, "the type of this value must be known in this context");
       }

src/test/compile-fail/issue-2149.rs

@@ -0,0 +1,14 @@
+iface monad<A> {
+    fn bind<B>(fn(A) -> self<B>);
+}
+impl monad<A> of monad<A> for [A] {
+    fn bind<B>(f: fn(A) -> [B]) {
+        let mut r = fail;
+        for self.each {|elt| r += f(elt); }
+        //!^ WARNING unreachable expression
+        //!^^ ERROR the type of this value must be known
+   }
+}
+fn main() {
+    ["hi"].bind {|x| [x] };
+}

src/test/compile-fail/issue-2150.rs

@@ -0,0 +1,8 @@
+fn fail_len(v: [const int]) -> uint {
+    let mut i = fail;
+    for v.each {|x| i += 1u; }
+    //!^ WARNING unreachable statement
+    //!^^ ERROR the type of this value must be known
+    ret i;
+}
+fn main() {}

src/test/compile-fail/issue-2151.rs

@@ -0,0 +1,6 @@
+fn main() {
+    vec::iter(fail) {|i|
+        log (debug, i * 2);
+        //!^ ERROR the type of this value must be known
+   };
+}

src/test/compile-fail/unreachable-code-1.rs

@@ -0,0 +1,14 @@
+// xfail-pretty
+
+fn id(x: bool) -> bool { x }
+
+fn call_id() {
+    let c <- fail;
+    id(c); //! WARNING unreachable statement
+}
+
+fn call_id_3() { id(ret) && id(ret); }
+    //!^ ERROR the type of this value must be known
+
+fn main() {
+}

src/test/pretty/disamb-stmt-expr.rs

@@ -4,5 +4,7 @@
 // preserved.  They are needed to disambiguate `{ret n+1}; - 0` from
 // `({ret n+1}-0)`.
 
-fn wsucc(n: int) -> int { ({ ret n + 1 }) - 0; }
+fn id(f: fn() -> int) -> int { f() }
+
+fn wsucc(n: int) -> int { (id {|| 1 }) - 0 }
 fn main() { }

src/test/run-pass/early-ret-binop-add.rs

@@ -1,2 +1,2 @@
-fn wsucc(n: int) -> int { ({ ret n + 1 } + 0); }
+fn wsucc(n: int) -> int { 0 + { ret n + 1 } }
 fn main() { }

src/test/run-pass/unreachable-code.rs

@@ -9,8 +9,6 @@ fn call_id() {
 
 fn call_id_2() { id(true) && id(ret); }
 
-fn call_id_3() { id(ret) && id(ret); }
-
 fn call_id_4() { while id(ret) { } }
 
 fn bind_id_1() { bind id(fail); }
@@ -27,7 +25,7 @@ fn log_break() { loop { log(error, break); } }
 
 fn log_cont() { do { log(error, cont); } while false }
 
-fn ret_ret() -> int { ret (ret 2) + 3; }
+fn ret_ret() -> int { ret 3 + (ret 2); }
 
 fn ret_guard() {
     alt check 2 {
@@ -53,7 +51,6 @@ fn main() {
   ret_ret();
   log_ret();
   call_id_2();
-  call_id_3();
   call_id_4();
   bind_id_2();
   ret_guard();