2.1.60 [ECMA-262/6] Section 15.1.1 Static Semantics: Early Errors

V0069: Duplicate function and generator function entries are allowed in LexicallyDeclaredNames of ScriptBody

The specification states:

 15.1.1 Static Semantics: Early Errors
  
     Script : ScriptBody
  
         • It is a Syntax Error if the LexicallyDeclaredNames of ScriptBody contains any 
         duplicate entries.
         • It is a Syntax Error if any element of the LexicallyDeclaredNames of ScriptBody 
         also occurs in the VarDeclaredNames of ScriptBody.

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Duplicate function and generator function entries are allowed in LexicallyDeclaredNames of ScriptBody.