From 77f467cd982edceff865feee017b8074db387f42 Mon Sep 17 00:00:00 2001
From: Eduard Urbach <eduard@urbach.dev>
Date: Sun, 27 Sep 2026 11:28:28 +0200
Subject: [PATCH] Implemented copy removal

---
 src/config/Build.go           |  1 +
 src/config/Optimize.go        |  1 +
 src/core/errors_test.go       |  2 +-
 src/core/optimize.go          |  5 +++++
 src/optimizer/RemoveCopies.go | 36 +++++++++++++++++++++++++++++++++++
 src/ssa/IR.go                 |  4 ++++
 6 files changed, 48 insertions(+), 1 deletion(-)
 create mode 100644 src/optimizer/RemoveCopies.go

diff --git a/src/config/Build.go b/src/config/Build.go
index 52d1c34..3c06763 100644
--- a/src/config/Build.go
+++ b/src/config/Build.go
@@ -7,6 +7,7 @@ type Build struct {
 	OS                   OS
 	Dry                  bool
 	Fold                 bool
+	RemoveCopies         bool
 	Reorder              bool
 	LintAssertionDensity bool
 	LintBinaryOps        bool
diff --git a/src/config/Optimize.go b/src/config/Optimize.go
index 690a563..f0a2aab 100644
--- a/src/config/Optimize.go
+++ b/src/config/Optimize.go
@@ -3,5 +3,6 @@ package config
 // Optimize enables or disables the optimizer.
 func (build *Build) Optimize(enabled bool) {
 	build.Fold = enabled
+	build.RemoveCopies = enabled
 	build.Reorder = enabled
 }
\ No newline at end of file
diff --git a/src/core/errors_test.go b/src/core/errors_test.go
index 329c8e8..f3db859 100644
--- a/src/core/errors_test.go
+++ b/src/core/errors_test.go
@@ -117,7 +117,7 @@ var errs = []struct {
 	{"UnusedValue3.q", &core.UnusedValue{Value: "\"not used\""}},
 	{"UnusedValue4.q", &core.UnusedValue{Value: "1"}},
 	{"UnusedValue5.q", &core.UnusedValue{Value: "x - 1"}},
-	{"UnusedValue6.q", &core.UnusedValue{Value: "x"}},
+	{"UnusedValue6.q", &core.UnusedValue{Value: "0"}},
 	{"UnusedValue7.q", &core.UnusedValue{Value: "1"}},
 	{"UnusedValue8.q", &core.UnusedValue{Value: "1 + 1"}},
 	{"VariableAlreadyExists.q", &core.VariableAlreadyExists{Name: "x"}},
diff --git a/src/core/optimize.go b/src/core/optimize.go
index c560396..a8dc2af 100644
--- a/src/core/optimize.go
+++ b/src/core/optimize.go
@@ -45,6 +45,11 @@ func (f *Function) optimize() error {
 		folded = optimizer.Fold(f.IR)
 	}
 
+	// Replace copies with their actual values.
+	if f.Env.Build.RemoveCopies {
+		optimizer.RemoveCopies(&f.IR)
+	}
+
 	// After cleaning up some of the instructions we can proceed
 	// to calculate the list of users.
 	f.ComputeUsers()
diff --git a/src/optimizer/RemoveCopies.go b/src/optimizer/RemoveCopies.go
new file mode 100644
index 0000000..7b7fd30
--- /dev/null
+++ b/src/optimizer/RemoveCopies.go
@@ -0,0 +1,36 @@
+package optimizer
+
+import (
+	"git.urbach.dev/cli/q/src/ssa"
+	"git.urbach.dev/cli/q/src/types"
+)
+
+// RemoveCopies replaces copies with their actual values.
+func RemoveCopies(ir *ssa.IR) {
+	for _, block := range ir.Blocks {
+		for i, value := range block.Instructions {
+			copy, isCopy := value.(*ssa.Copy)
+
+			if !isCopy {
+				continue
+			}
+
+			typ := copy.Value.Type()
+
+			if copy.Typ != typ {
+				continue
+			}
+
+			_, isResource := typ.(*types.Resource)
+
+			if isResource {
+				continue
+			}
+
+			ir.ReplaceAll(copy, copy.Value)
+			block.RemoveAt(i)
+		}
+
+		block.RemoveNilValues()
+	}
+}
\ No newline at end of file
diff --git a/src/ssa/IR.go b/src/ssa/IR.go
index f8a6188..fc470d9 100644
--- a/src/ssa/IR.go
+++ b/src/ssa/IR.go
@@ -79,6 +79,10 @@ func (ir *IR) IsIdentified(value Value) bool {
 func (ir *IR) ReplaceAll(old Value, new Value) {
 	for _, block := range ir.Blocks {
 		for _, value := range block.Instructions {
+			if value == nil {
+				continue
+			}
+
 			value.Replace(old, new)
 		}
 	}
-- 
2.51.2