fix array copy; ci: test prebuilt Windows package

.github/workflows/ci.yml

@@ -162,8 +162,14 @@ jobs:
   windows-prebuilt:
     runs-on: windows-2019
     steps:
+      shell: bash
     - name: Download V
-      run: echo "test" #wget https://github.com/vbinaries/vbinaries/releases/download/latest/v_windows.zip && unzip v_windows.zip && ./v.exe --version
+      run: |
+        echo "Downloading v.exe..."
+        wget https://github.com/vbinaries/vbinaries/releases/download/latest/v_windows.zip
+        unzip v_windows.zip
+        ./v.exe --version
+        echo "Done"
     - name: Test V
       run: echo "test" #./v.exe examples/hello_world.v && examples/hello_world.exe
 

vlib/builtin/array.v

@@ -368,7 +368,7 @@ pub fn (b []byte) hex() string {
 pub fn copy(dst, src []byte) int {
 	if dst.len > 0 && src.len > 0 {
 		min := if dst.len < src.len { dst.len } else { src.len }
-		C.memcpy(dst.data, src[min..].data, dst.element_size * min)
+		C.memcpy(dst.data, src[..min].data, dst.element_size * min)
 		return min
 	}
 	return 0