From 7657d5b192c28e44a072568bd8df377bf7a2d4bd Mon Sep 17 00:00:00 2001
From: rvcas <x@rvcas.dev>
Date: Mon, 29 Nov 2021 15:06:45 -0500
Subject: [PATCH 1/3] test: enable wasm in gen_list

---
 compiler/test_gen/src/gen_list.rs | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/compiler/test_gen/src/gen_list.rs b/compiler/test_gen/src/gen_list.rs
index 3ed20624f1..42999c5e6c 100644
--- a/compiler/test_gen/src/gen_list.rs
+++ b/compiler/test_gen/src/gen_list.rs
@@ -1,13 +1,11 @@
-#![cfg(feature = "gen-llvm")]
-
 #[cfg(feature = "gen-llvm")]
 use crate::helpers::llvm::assert_evals_to;
 
 // #[cfg(feature = "gen-dev")]
 // use crate::helpers::dev::assert_evals_to;
 
-// #[cfg(feature = "gen-wasm")]
-// use crate::helpers::wasm::assert_evals_to;
+#[cfg(feature = "gen-wasm")]
+use crate::helpers::wasm::assert_evals_to;
 
 use crate::helpers::with_larger_debug_stack;
 //use crate::assert_wasm_evals_to as assert_evals_to;
@@ -22,7 +20,7 @@ fn roc_list_construction() {
 }
 
 #[test]
-#[cfg(any(feature = "gen-llvm"))]
+#[cfg(any(feature = "gen-llvm", feature = "gen-wasm"))]
 fn empty_list_literal() {
     assert_evals_to!("[]", RocList::from_slice(&[]), RocList<i64>);
 }
@@ -34,6 +32,7 @@ fn list_literal_empty_record() {
 }
 
 #[test]
+#[cfg(any(feature = "gen-llvm"))]
 fn int_singleton_list_literal() {
     assert_evals_to!("[1, 2]", RocList::from_slice(&[1, 2]), RocList<i64>);
 }

From 27e77f446f2361fd740248a7257f5ccea10e92ad Mon Sep 17 00:00:00 2001
From: rvcas <x@rvcas.dev>
Date: Mon, 29 Nov 2021 15:08:52 -0500
Subject: [PATCH 2/3] feat(wasm): implement EmptyArray

---
 compiler/gen_wasm/src/backend.rs | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/compiler/gen_wasm/src/backend.rs b/compiler/gen_wasm/src/backend.rs
index 4fd555d8e3..750b9521a9 100644
--- a/compiler/gen_wasm/src/backend.rs
+++ b/compiler/gen_wasm/src/backend.rs
@@ -561,6 +561,27 @@ impl<'a> WasmBackend<'a> {
                 Ok(())
             }
 
+            Expr::Array { .. } => Err(format!("Expression is not yet implemented {:?}", 2)),
+
+            Expr::EmptyArray => {
+                if let StoredValue::StackMemory { location, .. } = storage {
+                    let (local_id, offset) =
+                        location.local_and_offset(self.storage.stack_frame_pointer);
+
+                    // This is a minor cheat. We only need the first two 32 bit
+                    // chunks here. We fill both chunks with zeros, so we
+                    // can simplify things to a single group of 64 bit operations instead of
+                    // doing the below twice for 32 bits.
+                    self.code_builder.get_local(local_id);
+                    self.code_builder.i64_const(0);
+                    self.code_builder.i64_store(Align::Bytes4, offset);
+
+                    Ok(())
+                } else {
+                    unreachable!("Unexpected storage for {:?}", sym)
+                }
+            }
+
             x => Err(format!("Expression is not yet implemented {:?}", x)),
         }
     }

From 6305947b1a87ab47f5c4ed4e6800ca4140551af6 Mon Sep 17 00:00:00 2001
From: rvcas <x@rvcas.dev>
Date: Mon, 29 Nov 2021 18:08:12 -0500
Subject: [PATCH 3/3] fix: exclude gen-dev from gen_list test compilation

---
 compiler/test_gen/src/gen_list.rs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/compiler/test_gen/src/gen_list.rs b/compiler/test_gen/src/gen_list.rs
index 42999c5e6c..34e02bfff8 100644
--- a/compiler/test_gen/src/gen_list.rs
+++ b/compiler/test_gen/src/gen_list.rs
@@ -1,3 +1,6 @@
+#![cfg(feature = "gen-llvm")]
+#![cfg(feature = "gen-wasm")]
+
 #[cfg(feature = "gen-llvm")]
 use crate::helpers::llvm::assert_evals_to;