Also simplify types of lambda parameters.
Also simplify types of lambda parameters.

ihc/futhark,mrakgr/futhark,ihc/futhark,mrakgr/futhark,diku-dk/futhark,diku-dk/futhark,diku-dk/futhark,CulpaBS/wbBach,ihc/futhark,HIPERFIT/futhark,mrakgr/futhark,HIPERFIT/futhark,diku-dk/futhark,HIPERFIT/futhark,diku-dk/futhark