-- Acutal and expected types
unifyTheta theta1 theta2
= do { checkTc (equalLength theta1 theta2)
- (ptext SLIT("Contexts differ in length"))
+ (vcat [ptext SLIT("Contexts differ in length"),
+ nest 2 $ parens $ ptext SLIT("Use -fglasgow-exts to allow this")])
; uList unifyPred theta1 theta2 }
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