From 80e95c9a18962c1e41805d7754f9bc2253356656 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Johannes=20M=C3=BCller?= <straightshoota@gmail.com>
Date: Tue, 10 Jan 2023 16:43:44 +0100
Subject: [PATCH 1/2] Add `Tuple#to_static_array`

---
 spec/std/tuple_spec.cr | 11 +++++++++++
 src/tuple.cr           | 18 ++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/spec/std/tuple_spec.cr b/spec/std/tuple_spec.cr
index 22d8d40933d0..a5a589f193d0 100644
--- a/spec/std/tuple_spec.cr
+++ b/spec/std/tuple_spec.cr
@@ -341,4 +341,15 @@ describe "Tuple" do
     ary = Tuple.new.to_a
     ary.size.should eq(0)
   end
+
+  it "#to_static_array" do
+    ary = {1, 'a', true}.to_static_array
+    ary.should be_a(StaticArray(Int32 | Char | Bool, 3))
+    ary.should eq(StaticArray[1, 'a', true])
+    ary.size.should eq(3)
+
+    ary = Tuple.new.to_static_array
+    ary.should be_a(StaticArray(NoReturn, 0))
+    ary.size.should eq(0)
+  end
 end
diff --git a/src/tuple.cr b/src/tuple.cr
index 16d2675243c8..a3815c856278 100644
--- a/src/tuple.cr
+++ b/src/tuple.cr
@@ -548,6 +548,24 @@ struct Tuple
     end
   end
 
+  # Returns a `StaticArray` with the same elements.
+  #
+  # The element type is `Union(*T)`.
+  #
+  # ```
+  # {1, 'a', true}.to_static_array # => StaticArray[1, 'a', true]
+  # ```
+  @[AlwaysInline]
+  def to_static_array : StaticArray
+    {% begin %}
+      ary = uninitialized StaticArray(Union(*T), {{ T.size }})
+      each_with_index do |value, i|
+        ary.to_unsafe[i] = value
+      end
+      ary
+    {% end %}
+  end
+
   # Appends a string representation of this tuple to the given `IO`.
   #
   # ```

From 7cf2bd16271231f2d029125b761320b9914880fb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Johannes=20M=C3=BCller?= <straightshoota@gmail.com>
Date: Wed, 11 Jan 2023 15:43:43 +0100
Subject: [PATCH 2/2] Add test case for downcast type

---
 spec/std/tuple_spec.cr | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/spec/std/tuple_spec.cr b/spec/std/tuple_spec.cr
index a5a589f193d0..c6ead7b1ccf6 100644
--- a/spec/std/tuple_spec.cr
+++ b/spec/std/tuple_spec.cr
@@ -351,5 +351,9 @@ describe "Tuple" do
     ary = Tuple.new.to_static_array
     ary.should be_a(StaticArray(NoReturn, 0))
     ary.size.should eq(0)
+
+    ary = Tuple(String | Int32).new(1).to_static_array
+    ary.should be_a(StaticArray(String | Int32, 1))
+    ary.should eq StaticArray[1.as(String | Int32)]
   end
 end