Delphi Error – W1074 Unknown Custom Attribute

Delphi Compiler Error

W1074 Unknown Custom Attribute

Reason for the Error & Solution

This message indicates that the class used for this attribute was not found.

Note: When this warning is set to False, the Unsupported language warning is generated.


  [ThisIsAFakeAttribute('Hello', 10)] // This generates 'the "Warning: W1074 Unknown custom attribute"
  TTestClass = class
{$WARN UNKNOWN_CUSTOM_ATTRIBUTE OFF}  // Here we disable the generation of W1074
  [ThisIsAFakeAttribute('Hello', 10)] // Now, this generates the "Warning: W1025 Unsupported language feature: 'custom attribute'"
  TTestClass2 = class

See Also