From 56c751e7ec94e8dc9cc4b50aa196f156d6047cd1 Mon Sep 17 00:00:00 2001
From: Eduard Urbach <eduard@urbach.dev>
Date: Fri, 3 Jul 2026 21:01:58 +0200
Subject: [PATCH] Refactored ssa value interface

---
 src/ssa/HasUsers.go | 12 ++++++++++++
 src/ssa/Liveness.go |  3 +++
 src/ssa/Value.go    | 10 ++--------
 src/ssa/Void.go     |  3 +++
 4 files changed, 20 insertions(+), 8 deletions(-)
 create mode 100644 src/ssa/HasUsers.go

diff --git a/src/ssa/HasUsers.go b/src/ssa/HasUsers.go
new file mode 100644
index 0000000..67dace9
--- /dev/null
+++ b/src/ssa/HasUsers.go
@@ -0,0 +1,12 @@
+package ssa
+
+type HasUsers interface {
+	// AddUser adds a new user of this value.
+	AddUser(Value)
+
+	// RemoveUser removes an existing user of this value.
+	RemoveUser(Value)
+
+	// Users returns all values that reference this value as an input.
+	Users() []Value
+}
\ No newline at end of file
diff --git a/src/ssa/Liveness.go b/src/ssa/Liveness.go
index 9e93578..368b6f7 100644
--- a/src/ssa/Liveness.go
+++ b/src/ssa/Liveness.go
@@ -5,6 +5,9 @@ type Liveness struct {
 	users []Value
 }
 
+// Force interface implementation.
+var _ HasUsers = (*Liveness)(nil)
+
 // AddUser adds a new user of the value.
 func (l *Liveness) AddUser(user Value) {
 	l.users = append(l.users, user)
diff --git a/src/ssa/Value.go b/src/ssa/Value.go
index f514d39..81a1825 100644
--- a/src/ssa/Value.go
+++ b/src/ssa/Value.go
@@ -3,9 +3,6 @@ package ssa
 import "git.urbach.dev/cli/q/src/types"
 
 type Value interface {
-	// AddUser adds a new user of this value.
-	AddUser(Value)
-
 	// Equals check for equality which is useful for common subexpression elimination.
 	Equals(Value) bool
 
@@ -15,9 +12,6 @@ type Value interface {
 	// IsPure returns true if the calculation of the value has no side effects.
 	IsPure() bool
 
-	// RemoveUser removes an existing user of this value.
-	RemoveUser(Value)
-
 	// Replace replaces the uses of a value with another value.
 	Replace(Value, Value)
 
@@ -27,6 +21,6 @@ type Value interface {
 	// Type returns the data type of the value.
 	Type() types.Type
 
-	// Users returns all values that reference this value as an input.
-	Users() []Value
+	// HasUsers is an interface to track where this value is used.
+	HasUsers
 }
\ No newline at end of file
diff --git a/src/ssa/Void.go b/src/ssa/Void.go
index c741ac5..293e818 100644
--- a/src/ssa/Void.go
+++ b/src/ssa/Void.go
@@ -5,6 +5,9 @@ import "git.urbach.dev/cli/q/src/types"
 // Void is the absence of a value.
 type Void struct{}
 
+// Force interface implementation.
+var _ HasUsers = (*Void)(nil)
+
 // AddUser does nothing because a void value cannot be used as a dependency.
 func (v *Void) AddUser(Value) {}
 
-- 
2.51.2