-- wrapping the 'otherwise' in empty HsTyApp or HsWrap constructors
-- If it does, you'll get bogus overlap warnings
matchGuards (ExprStmt e _ _ : stmts) ctx rhs rhs_ty
- | isTrueLHsExpr e
- = matchGuards stmts ctx rhs rhs_ty
-
+ | Just addTicks <- isTrueLHsExpr e
+ = matchGuards stmts ctx rhs rhs_ty `thenDs` \ match_result ->
+ returnDs (adjustMatchResultDs addTicks match_result)
matchGuards (ExprStmt expr _ _ : stmts) ctx rhs rhs_ty
= matchGuards stmts ctx rhs rhs_ty `thenDs` \ match_result ->
dsLExpr expr `thenDs` \ pred_expr ->
dsLExpr bind_rhs `thenDs` \ core_rhs ->
matchSinglePat core_rhs ctx pat rhs_ty match_result
-isTrueLHsExpr :: LHsExpr Id -> Bool
--- Returns True if we're sure that the expression is True
+isTrueLHsExpr :: LHsExpr Id -> Maybe (CoreExpr -> DsM CoreExpr)
+
+-- Returns Just {..} if we're sure that the expression is True
-- I.e. * 'True' datacon
-- * 'otherwise' Id
-- * Trivial wappings of these
-isTrueLHsExpr (L _ (HsVar v)) = v `hasKey` otherwiseIdKey
+-- The arguments to Just are any HsTicks that we have found,
+-- because we still want to tick then, even it they are aways evaluted.
+isTrueLHsExpr (L _ (HsVar v)) | v `hasKey` otherwiseIdKey
|| v `hasKey` getUnique trueDataConId
+ = Just returnDs
-- trueDataConId doesn't have the same unique as trueDataCon
-isTrueLHsExpr (L _ (HsTick _ _ e)) = isTrueLHsExpr e
-isTrueLHsExpr (L _ (HsBinTick _ _ e)) = isTrueLHsExpr e
+isTrueLHsExpr (L loc (HsTick ix frees e))
+ | Just ticks <- isTrueLHsExpr e = Just (\ e1 ->
+ ticks e1 `thenDs` \ e2 ->
+ mkTickBox ix frees e2)
+ -- This encodes that the result is constant True for Hpc tick purposes;
+ -- which is specifically what isTrueLHsExpr is trying to find out.
+isTrueLHsExpr (L loc (HsBinTick ixT _ e))
+ | Just ticks <- isTrueLHsExpr e = Just (\ e1 ->
+ ticks e1 `thenDs` \ e2 ->
+ mkTickBox ixT [] e2)
isTrueLHsExpr (L _ (HsPar e)) = isTrueLHsExpr e
-isTrueLHsExpr other = False
+isTrueLHsExpr other = Nothing
\end{code}
Should {\em fail} if @e@ returns @D@