Fix fragment slots adding data to vertex description

ShaderGraph/com.unity.shadergraph/Editor/Data/MasterNodes/PBRMasterNode.cs

         {
             List<MaterialSlot> slots = new List<MaterialSlot>();
             GetSlots(slots);
+
+            List<MaterialSlot> validSlots = new List<MaterialSlot>();
-                    slots.Remove(slots[i]);
-
+                    continue;
+                
+                validSlots.Add(slots[i]);
-            return slots.OfType<IMayRequireNormal>().Aggregate(NeededCoordinateSpace.None, (mask, node) => mask | node.RequiresNormal(stageCapability));
+            return validSlots.OfType<IMayRequireNormal>().Aggregate(NeededCoordinateSpace.None, (mask, node) => mask | node.RequiresNormal(stageCapability));
         }
 
         public NeededCoordinateSpace RequiresPosition(ShaderStageCapability stageCapability)
+            
+            List<MaterialSlot> validSlots = new List<MaterialSlot>();
-                    slots.Remove(slots[i]);
-
+                    continue;
+                
+                validSlots.Add(slots[i]);
-            return slots.OfType<IMayRequirePosition>().Aggregate(NeededCoordinateSpace.None, (mask, node) => mask | node.RequiresPosition(stageCapability));
+            return validSlots.OfType<IMayRequirePosition>().Aggregate(NeededCoordinateSpace.None, (mask, node) => mask | node.RequiresPosition(stageCapability));
         }
     }
 }

ShaderGraph/com.unity.shadergraph/Editor/Data/MasterNodes/UnlitMasterNode.cs

         {
             List<MaterialSlot> slots = new List<MaterialSlot>();
             GetSlots(slots);
+            
+            List<MaterialSlot> validSlots = new List<MaterialSlot>();
-                    slots.Remove(slots[i]);
-
+                    continue;
+                
+                validSlots.Add(slots[i]);
-            return slots.OfType<IMayRequirePosition>().Aggregate(NeededCoordinateSpace.None, (mask, node) => mask | node.RequiresPosition(stageCapability));
+            return validSlots.OfType<IMayRequirePosition>().Aggregate(NeededCoordinateSpace.None, (mask, node) => mask | node.RequiresPosition(stageCapability));
         }
     }
 }

ShaderGraph/com.unity.shadergraph/Editor/Data/Nodes/MasterNode.cs

             foreach (var activeNode in activeNodeList.OfType<AbstractMaterialNode>())
                 activeNode.CollectShaderProperties(shaderProperties, mode);
 
-            var finalShader = new ShaderGenerator();
-            finalShader.AddShaderChunk(string.Format(@"Shader ""{0}""", outputName), false);
-            finalShader.AddShaderChunk("{", false);
-            finalShader.Indent();
-
-            finalShader.AddShaderChunk("Properties", false);
-            finalShader.AddShaderChunk("{", false);
-            finalShader.Indent();
-            finalShader.AddShaderChunk(shaderProperties.GetPropertiesBlock(0), false);
-            finalShader.Deindent();
-            finalShader.AddShaderChunk("}", false);
-
-            foreach (var subShader in m_SubShaders)
-                finalShader.AddShaderChunk(subShader.GetSubshader(this, mode), true);
-
-            finalShader.AddShaderChunk(@"FallBack ""Hidden/InternalErrorShader""", false);
-            finalShader.Deindent();
-            finalShader.AddShaderChunk("}", false);
+            var finalShader = new ShaderStringBuilder();
+            finalShader.AppendLine(@"Shader ""{0}""", outputName);
+            using(finalShader.BlockScope())
+            {
+                finalShader.AppendLine("Properties");
+                using(finalShader.BlockScope())
+                {
+                    finalShader.AppendLine(shaderProperties.GetPropertiesBlock(0));
+                }
+                foreach (var subShader in m_SubShaders)
+                    finalShader.AppendLines(subShader.GetSubshader(this, mode));
+                
+                finalShader.AppendLine(@"FallBack ""Hidden/InternalErrorShader""");
+            }
-            return finalShader.GetShaderString(0);
+            return finalShader.ToString();
         }
 
         public bool IsPipelineCompatible(IRenderPipeline renderPipeline)