Aggressive constprop in Fun * Operator (#280)

Author: jishnub

src/Operators/general/algebra.jl

@@ -573,15 +573,22 @@ end
 -(A::Operator) = ConstantTimesOperator(-1,A)
 -(A::Operator,B::Operator) = A+(-B)
 
-
-function *(f::Fun, A::Operator)
+@inline function _mulop(f::Fun, A::Operator)
     if isafunctional(A) && (isinf(bandwidth(A,1)) || isinf(bandwidth(A,2)))
         LowRankOperator(f,A)
     else
         TimesOperator(Multiplication(f,rangespace(A)),A)
     end
 end
 
+@static if VERSION >= v"1.8"
+    Base.@constprop :aggressive function *(f::Fun, A::Operator)
+        _mulop(f, A)
+    end
+else
+    *(f::Fun, A::Operator) = _mulop(f, A)
+end
+
 *(c::Number,A::Operator) = ConstantTimesOperator(c,A)
 *(A::Operator,c::Number) = c*A