diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 030b891..96a165f 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -17,22 +17,25 @@ on:
 env:
   # Currently no way to detect automatically
   DEFAULT_BRANCH: main
-  GO_VERSION: 1.20.5 # renovate: datasource=golang-version depName=golang
+  GO_VERSION: 1.20.6 # renovate: datasource=golang-version depName=golang
   NODE_VERSION: 18
   DRY_RUN: true
 
 jobs:
   build:
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        go-version: [ '1.20.x', '1.21.x' ]
     steps:
       # full checkout for semantic-release
       - uses: actions/checkout@c85c95e3d7251135ab7dc9ce3241c5835cc595a9 # v3.5.3
         with:
           fetch-depth: 0
-      - name: Set up go ${{env.GO_VERSION}}
+      - name: Set up go ${{ matrix.go-version }}
         uses: actions/setup-go@v4
         with:
-          go-version: ${{env.GO_VERSION}}
+          go-version: ${{ matrix.go-version }}
       -
         name: Tests
         run: |
diff --git a/record/generic/semigroup.go b/record/generic/semigroup.go
index 8faaa8d..f1de1e7 100644
--- a/record/generic/semigroup.go
+++ b/record/generic/semigroup.go
@@ -21,18 +21,18 @@ import (
 
 func UnionSemigroup[N ~map[K]V, K comparable, V any](s S.Semigroup[V]) S.Semigroup[N] {
 	return S.MakeSemigroup(func(first N, second N) N {
-		return union(s, first, second)
+		return union[N, K, V](S.ToMagma(s), first, second)
 	})
 }
 
 func UnionLastSemigroup[N ~map[K]V, K comparable, V any]() S.Semigroup[N] {
 	return S.MakeSemigroup(func(first N, second N) N {
-		return unionLast(first, second)
+		return unionLast[N, K, V](first, second)
 	})
 }
 
 func UnionFirstSemigroup[N ~map[K]V, K comparable, V any]() S.Semigroup[N] {
 	return S.MakeSemigroup(func(first N, second N) N {
-		return unionLast(second, first)
+		return unionLast[N, K, V](second, first)
 	})
 }
diff --git a/semigroup/semigroup.go b/semigroup/semigroup.go
index 3eb8d76..298035c 100644
--- a/semigroup/semigroup.go
+++ b/semigroup/semigroup.go
@@ -59,3 +59,8 @@ func First[A any]() Semigroup[A] {
 func Last[A any]() Semigroup[A] {
 	return MakeSemigroup(F.Second[A, A])
 }
+
+// ToMagma converts a semigroup to a magma
+func ToMagma[A any](s Semigroup[A]) M.Magma[A] {
+	return s
+}