diff --git a/src/librustc_mir/interpret/eval_context.rs b/src/librustc_mir/interpret/eval_context.rs
index 9f37b3521dcbb..e25fb145e753e 100644
--- a/src/librustc_mir/interpret/eval_context.rs
+++ b/src/librustc_mir/interpret/eval_context.rs
@@ -690,7 +690,7 @@ impl<'a, 'tcx, M: Machine<'tcx>> EvalContext<'a, 'tcx, M> {
                         }
                     }
 
-                    StructWrappedNullablePointer { nndiscr, ref discrfield, .. } => {
+                    StructWrappedNullablePointer { nndiscr, ref discrfield_source, .. } => {
                         if let mir::AggregateKind::Adt(_, variant, _, _) = **kind {
                             if nndiscr == variant as u64 {
                                 self.assign_fields(dest, dest_ty, operands)?;
@@ -699,7 +699,7 @@ impl<'a, 'tcx, M: Machine<'tcx>> EvalContext<'a, 'tcx, M> {
                                     let operand_ty = self.operand_ty(operand);
                                     assert_eq!(self.type_size(operand_ty)?, Some(0));
                                 }
-                                let (offset, TyAndPacked { ty, packed: _}) = self.nonnull_offset_and_ty(dest_ty, nndiscr, discrfield)?;
+                                let (offset, TyAndPacked { ty, packed: _}) = self.nonnull_offset_and_ty(dest_ty, nndiscr, discrfield_source)?;
                                 // TODO: The packed flag is ignored
 
                                 // FIXME(solson)
diff --git a/src/librustc_mir/interpret/step.rs b/src/librustc_mir/interpret/step.rs
index 7ad51a08a4656..6ecaba5ccb857 100644
--- a/src/librustc_mir/interpret/step.rs
+++ b/src/librustc_mir/interpret/step.rs
@@ -104,9 +104,9 @@ impl<'a, 'tcx, M: Machine<'tcx>> EvalContext<'a, 'tcx, M> {
                         }
                     }
 
-                    Layout::StructWrappedNullablePointer { nndiscr, ref discrfield, .. } => {
+                    Layout::StructWrappedNullablePointer { nndiscr, ref discrfield_source, .. } => {
                         if variant_index as u64 != nndiscr {
-                            let (offset, TyAndPacked { ty, packed }) = self.nonnull_offset_and_ty(dest_ty, nndiscr, discrfield)?;
+                            let (offset, TyAndPacked { ty, packed }) = self.nonnull_offset_and_ty(dest_ty, nndiscr, discrfield_source)?;
                             let nonnull = self.force_allocation(dest)?.to_ptr()?.offset(offset.bytes(), &self)?;
                             trace!("struct wrapped nullable pointer type: {}", ty);
                             // only the pointer part of a fat pointer is used for this space optimization
diff --git a/src/librustc_mir/interpret/terminator/mod.rs b/src/librustc_mir/interpret/terminator/mod.rs
index ce04e1b8d1e06..b9447a30ab154 100644
--- a/src/librustc_mir/interpret/terminator/mod.rs
+++ b/src/librustc_mir/interpret/terminator/mod.rs
@@ -440,8 +440,8 @@ impl<'a, 'tcx, M: Machine<'tcx>> EvalContext<'a, 'tcx, M> {
                 self.read_nonnull_discriminant_value(adt_ptr, nndiscr as u128, discr_size)?
             }
 
-            StructWrappedNullablePointer { nndiscr, ref discrfield, .. } => {
-                let (offset, TyAndPacked { ty, packed }) = self.nonnull_offset_and_ty(adt_ty, nndiscr, discrfield)?;
+            StructWrappedNullablePointer { nndiscr, ref discrfield_source, .. } => {
+                let (offset, TyAndPacked { ty, packed }) = self.nonnull_offset_and_ty(adt_ty, nndiscr, discrfield_source)?;
                 let nonnull = adt_ptr.offset(offset.bytes(), &*self)?;
                 trace!("struct wrapped nullable pointer type: {}", ty);
                 // only the pointer part of a fat pointer is used for this space optimization
diff --git a/tests/run-pass/issue-29746.rs b/tests/run-pass/issue-29746.rs
new file mode 100644
index 0000000000000..61c601ac6a903
--- /dev/null
+++ b/tests/run-pass/issue-29746.rs
@@ -0,0 +1,45 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// zip!(a1,a2,a3,a4) is equivalent to:
+//  a1.zip(a2).zip(a3).zip(a4).map(|(((x1,x2),x3),x4)| (x1,x2,x3,x4))
+macro_rules! zip {
+    // Entry point
+    ([$a:expr, $b:expr, $($rest:expr),*]) => {
+        zip!([$($rest),*], $a.zip($b), (x,y), [x,y])
+    };
+
+    // Intermediate steps to build the zipped expression, the match pattern, and
+    //  and the output tuple of the closure, using macro hygene to repeatedly
+    //  introduce new variables named 'x'.
+    ([$a:expr, $($rest:expr),*], $zip:expr, $pat:pat, [$($flat:expr),*]) => {
+        zip!([$($rest),*], $zip.zip($a), ($pat,x), [$($flat),*, x])
+    };
+
+    // Final step
+    ([], $zip:expr, $pat:pat, [$($flat:expr),+]) => {
+        $zip.map(|$pat| ($($flat),+))
+    };
+
+    // Comma
+    ([$a:expr], $zip:expr, $pat:pat, [$($flat:expr),*]) => {
+        zip!([$a,], $zip, $pat, [$($flat),*])
+    };
+}
+
+fn main() {
+    let p1 = vec![1i32,    2].into_iter();
+    let p2 = vec!["10",    "20"].into_iter();
+    let p3 = vec![100u16,  200].into_iter();
+    let p4 = vec![1000i64, 2000].into_iter();
+
+    let e = zip!([p1,p2,p3,p4]).collect::<Vec<_>>();
+    assert_eq!(e[0], (1i32,"10",100u16,1000i64));
+}