ASTGen: Resolve 'was defined but never used' warnings.

Author: tshortli

lib/ASTGen/Sources/ASTGen/DeclAttrs.swift

@@ -367,6 +367,7 @@ extension ASTGenVisitor {
       return []
     }
 
+    _ = args
     fatalError("unimplemented")
   }
 
@@ -757,6 +758,7 @@ extension ASTGenVisitor {
       return []
     }
 
+    _ = args
     fatalError("unimplemented")
   }
 
@@ -939,6 +941,8 @@ extension ASTGenVisitor {
       // TODO: Diagnose.
       return nil
     }
+
+    _ = args
     fatalError("unimplemented")
   }
 

lib/ASTGen/Sources/ASTGen/Exprs.swift

@@ -266,6 +266,7 @@ extension ASTGenVisitor {
 
     if let signature = node.signature {
       // FIXME: Translate the signature, capture list, 'in' location, etc.
+      _ = signature
       fatalError("unimplmented")
     } else {
       let lBraceLoc = self.generateSourceLoc(node.leftBrace)