Check IsPure before Match.

ICSharpCode.Decompiler/IL/Transforms/ExpressionTransforms.cs

@@ -319,10 +319,10 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 				return false;
 			if (!(inst.Arguments[1] is LdVirtFtn ldVirtFtn))
 				return false;
-			if (!inst.Arguments[0].Match(ldVirtFtn.Argument).Success)
-				return false;
 			if (!SemanticHelper.IsPure(inst.Arguments[0].Flags))
 				return false;
+			if (!inst.Arguments[0].Match(ldVirtFtn.Argument).Success)
+				return false;
 			ldVirtDelegate = new LdVirtDelegate(inst.Arguments[0], inst.Method.DeclaringType, ldVirtFtn.Method)
 				.WithILRange(inst).WithILRange(ldVirtFtn).WithILRange(ldVirtFtn.Argument);
 			return true;
@@ -531,10 +531,10 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 				return false;
 			if (!(dynamicCompoundAssign.Target is DynamicGetMemberInstruction getMember))
 				return false;
-			if (!isEvent.Argument.Match(getMember.Target).Success)
-				return false;
 			if (!SemanticHelper.IsPure(isEvent.Argument.Flags))
 				return false;
+			if (!isEvent.Argument.Match(getMember.Target).Success)
+				return false;
 			if (!(trueInst is DynamicInvokeMemberInstruction invokeMember))
 				return false;
 			if (!(invokeMember.BinderFlags.HasFlag(CSharpBinderFlags.InvokeSpecialName) && invokeMember.BinderFlags.HasFlag(CSharpBinderFlags.ResultDiscarded)))