Template haskell rejects duplicate instances before they're spliced

Suppose I want to see (from within ghci) how to write an instance declaration in the TH AST. I try:

Prelude> runQ $ [d| instance Monad Maybe where |]                                                                                                                                                                                                   
                                                                                                                                                                                                                                             
<interactive>:1:13:                                                                                                                                                                                                                          
    Duplicate instance declarations:                                                                                                                                                                                                         
      instance Monad Maybe -- Defined at <interactive>:1:13-23                                                                                                                                                                               
      instance Monad Maybe -- Defined in Data.Maybe                                                                                                                                                                                          
    In the Template Haskell quotation                                                                                                                                                                                                        
      [d|                                                                                                                                                                                                                                    
          instance Monad Maybe where |]                                                                                                                                                                                                      
    In the expression:                                                                                                                                                                                                                       
        [d|                                                                                                                                                                                                                                  
            instance Monad Maybe where |]                                                                                                                                                                                                    
    In the definition of `it':                                                                                                                                                                                                               
        it = [d|                                                                                                                                                                                                                             
                 instance Monad Maybe where |]

This seems ridiculous; I'm not trying to create an instance, just to create a TH AST fragment.

Trac metadata

Trac field	Value
Version	6.12.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Template Haskell
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture