rustc: Capture type parameters into for-each blocks. Add a test case.

src/comp/middle/trans.rs

@@ -3298,8 +3298,9 @@ fn trans_for_each(@block_ctxt cx,
     }
 
     // Create an environment and populate it with the bindings.
+    auto tydesc_count = _vec.len[ValueRef](cx.fcx.lltydescs);
     auto llenvptrty = T_closure_ptr(cx.fcx.ccx.tn, T_ptr(T_nil()),
-                                    val_ty(llbindingsptr), 0u);
+                                    val_ty(llbindingsptr), tydesc_count);
     auto llenvptr = alloca(cx, llvm.LLVMGetElementType(llenvptrty));
 
     auto llbindingsptrptr = cx.build.GEP(llenvptr,
@@ -3308,6 +3309,20 @@ fn trans_for_each(@block_ctxt cx,
                                              C_int(2)));
     cx.build.Store(llbindingsptr, llbindingsptrptr);
 
+    // Copy in our type descriptors, in case the iterator body needs to refer
+    // to them.
+    auto lltydescsptr = cx.build.GEP(llenvptr,
+                                     vec(C_int(0),
+                                         C_int(abi.box_rc_field_body),
+                                         C_int(3)));
+    auto i = 0u;
+    while (i < tydesc_count) {
+        auto lltydescptr = cx.build.GEP(lltydescsptr,
+                                        vec(C_int(0), C_int(i as int)));
+        cx.build.Store(cx.fcx.lltydescs.(i), lltydescptr);
+        i += 1u;
+    }
+
     // Step 2: Declare foreach body function.
 
     let str s = mangle_name_by_seq(cx.fcx.ccx, "foreach");
@@ -3339,7 +3354,7 @@ fn trans_for_each(@block_ctxt cx,
         vec(C_int(0), C_int(abi.box_rc_field_body), C_int(2)));
     auto llremotebindingsptr = bcx.build.Load(llremotebindingsptrptr);
 
-    auto i = 0u;
+    i = 0u;
     while (i < upvar_count) {
         auto upvar_id = upvars.(i);
         auto llupvarptrptr = bcx.build.GEP(llremotebindingsptr,
@@ -3350,6 +3365,22 @@ fn trans_for_each(@block_ctxt cx,
         i += 1u;
     }
 
+    // Populate the type parameters from the environment.
+    auto llremotetydescsptr = bcx.build.GEP(llremoteenvptr,
+                                            vec(C_int(0),
+                                                C_int(abi.box_rc_field_body),
+                                                C_int(3)));
+
+    i = 0u;
+    while (i < tydesc_count) {
+        auto llremotetydescptr = bcx.build.GEP(llremotetydescsptr,
+                                               vec(C_int(0),
+                                                   C_int(i as int)));
+        auto llremotetydesc = bcx.build.Load(llremotetydescptr);
+        fcx.lltydescs += vec(llremotetydesc);
+        i += 1u;
+    }
+
     // Treat the loop variable as an upvar as well. We copy it to an alloca
     // as usual.
     auto lllvar = llvm.LLVMGetParam(fcx.llfn, 3u);

src/test/run-pass/type-params-in-for-each.rs

@@ -0,0 +1,11 @@
+use std;
+import std._uint;
+
+fn create_index[T](vec[tup(T, uint)] index, fn(&T) -> uint hash_fn) {
+    for each (uint i in _uint.range(0u, 256u)) {
+        let vec[T] bucket = vec();
+    }
+}
+
+fn main() {}
+