From 7c7592023899ce23a058077d57a3ae10a27b2f7e Mon Sep 17 00:00:00 2001
From: abicky <takeshi.arabiki@gmail.com>
Date: Thu, 28 Jan 2021 01:56:34 +0900
Subject: [PATCH] Fix panic that occurs when a struct has a blank field

This commit fixes https://github.com/imdario/mergo/issues/174.
---
 issue174_test.go | 21 +++++++++++++++++++++
 merge.go         |  2 +-
 2 files changed, 22 insertions(+), 1 deletion(-)
 create mode 100644 issue174_test.go

diff --git a/issue174_test.go b/issue174_test.go
new file mode 100644
index 0000000..d06b68b
--- /dev/null
+++ b/issue174_test.go
@@ -0,0 +1,21 @@
+package mergo_test
+
+import (
+	"testing"
+
+	"github.com/imdario/mergo"
+)
+
+type structWithBlankField struct {
+	_ struct{}
+	A struct{}
+}
+
+func TestIssue174(t *testing.T) {
+	dst := structWithBlankField{}
+	src := structWithBlankField{}
+
+	if err := mergo.Merge(&dst, src, mergo.WithOverride); err != nil {
+		t.Error(err)
+	}
+}
diff --git a/merge.go b/merge.go
index afa84a1..3f13275 100644
--- a/merge.go
+++ b/merge.go
@@ -95,7 +95,7 @@ func deepMerge(dst, src reflect.Value, visited map[uintptr]*visit, depth int, co
 				}
 			}
 		} else {
-			if (isReflectNil(dst) || overwrite) && (!isEmptyValue(src) || overwriteWithEmptySrc) {
+			if dst.CanSet() && (isReflectNil(dst) || overwrite) && (!isEmptyValue(src) || overwriteWithEmptySrc) {
 				dst.Set(src)
 			}
 		}