Handle fail inside a for-each loop properly

Author: catamorphism

src/comp/middle/trans.rs

@@ -4564,7 +4564,11 @@ fn trans_for_each(&@block_ctxt cx, &@ast::local local, &@ast::expr seq,
     auto lltop = bcx.llbb;
     auto r = trans_block(bcx, body, return);
     finish_fn(fcx, lltop);
-    r.bcx.build.RetVoid();
+
+    if (!r.bcx.build.is_terminated()) {
+        // if terminated is true, no need for the ret-fail
+        r.bcx.build.RetVoid();
+    }
 
     // Step 3: Call iter passing [lliterbody, llenv], plus other args.
     alt (seq.node) {

src/test/run-fail/fail-main.rs

@@ -0,0 +1,7 @@
+// xfail-stage0
+// error-pattern:moop
+use std;
+import std::uint;
+fn main() {
+  fail "moop";
+}

src/test/run-fail/for-each-loop-fail.rs

@@ -0,0 +1,9 @@
+// xfail-stage0
+// error-pattern:moop
+use std;
+import std::uint;
+fn main() {
+  for each (uint i in uint::range(0u, 10u)) {
+    fail "moop";
+  }
+}

src/test/run-pass/for-loop-fail.rs

@@ -0,0 +1,7 @@
+// xfail-stage0
+fn main() {
+  let vec[int] x = [];
+  for (int i in x) {
+    fail "moop";
+  }
+}