Vertext program 'vert': Struct variable 'o' is ignored. error in 2017.3

Hi,
I've just upgraded my Unity from 2017.2.0f3 to 2017.3.0f3 and now I'm having an error on one of my shaders.

Error:
Vertex program 'vert': Struct variable 'o' is ignored. Only instancing constant buffers can have struct variables.

Code (CSharp):

1. // Upgrade NOTE: replaced 'mul(UNITY_MATRIX_MVP,*)' with 'UnityObjectToClipPos(*)'
2.  
3. Shader "Custom FX/Glow FX" {
4.     Properties
5.     {
6.         _MainTex ("Base (RGB), Alpha (A)", 2D) = "black" {}
7.         _MaskIntensity ("MaskIntensity", Float) = 1
8.         _CloudsTex ("Clouds", 2D) = "black" {}
9.         _CloudsScale ("Cloud Scale", Vector) = (1,1,0,0)
10.         _GradientTex ("Gradient Tex", 2D) = "black" {}
11.     }
12.    
13.     SubShader
14.     {
15.         LOD 200
16.  
17.         Tags
18.         {
19.             "Queue" = "Transparent"
20.             "IgnoreProjector" = "True"
21.             "RenderType" = "Transparent"
22.         }
23.        
24.         Pass
25.         {
26.             Cull Off
27.             Lighting Off
28.             ZWrite Off
29.             Blend One One
30.  
31.             CGPROGRAM
32.             #pragma vertex vert
33.             #pragma fragment frag
34.             #include "UnityCG.cginc"
35.  
36.             sampler2D _MainTex;
37.             sampler2D _GradientTex;
38.             sampler2D _CloudsTex;
39.             float4 _MainTex_ST;
40.             float4 _CloudsTex_ST;
41.             half2 _CloudsScale;
42.             fixed _MaskIntensity;
43.    
44.             struct appdata_t
45.             {
46.                 float4 vertex : POSITION;
47.                 float2 texcoord : TEXCOORD0;
48.                 fixed4 color : COLOR;
49.             };
50.    
51.             struct v2f
52.             {
53.                 float4 vertex : SV_POSITION;
54.                 half2 texcoord : TEXCOORD0;
55.                 half2 texcoord1 : TEXCOORD1;
56.                 half2 texcoord2 : TEXCOORD2;
57.                 float4 texcoord_clouds : TEXCOORD3;
58.             };
59.    
60.             v2f o;
61.  
62.             v2f vert (appdata_t v)
63.             {
64.                 o.vertex = UnityObjectToClipPos(v.vertex);
65.                 o.texcoord = v.texcoord;
66.                 o.texcoord_clouds.xy = v.texcoord * _CloudsScale.x + frac(_CloudsTex_ST.xy*_Time.y);
67.                 return o;
68.             }
69.                
70.             fixed4 frag (v2f IN) : COLOR
71.             {
72.                 fixed mask = tex2D(_MainTex, IN.texcoord).r;
73.                 fixed clouds = tex2D(_CloudsTex,IN.texcoord_clouds.xy);
74.                 fixed disValue = saturate(mask*_MaskIntensity + ((clouds) * mask));
75.                 fixed4 color = tex2D(_GradientTex, fixed2(disValue,0.5));
76.                 return color;
77.             }
78.             ENDCG
79.         }
80.     }
81. }
82.  

 

You probably need to move "v2f o;" inside "v2f vert (appdata_t v)".

 

Thanks! It worked and now the shader is working!

However, it now shows a different warning.

 

I solved it when I replaced "v2f o;" with "v2f o = (v2f)0;"
Thank you for your help

 

The warning that vert is not completely initialized is because you're not initializing your
half2 texcoord1 : TEXCOORD1;
half2 texcoord2 : TEXCOORD2;

(and if you're not doing anything with those two texcoords, you might as well delete them from your struct)