Fallback function broadcast zero check (#315)

* Fallback function broadcast zero check

* remove redundant check

Author: jishnub

src/generic/broadcast.jl

@@ -300,8 +300,6 @@ function _banded_broadcast!(dest::AbstractMatrix, f, (x,src)::Tuple{Number,Abstr
     d_l, d_u = bandwidths(dest)
     s_l, s_u = bandwidths(src)
 
-    checkzerobands(dest, f, src)
-
     _banded_broadcast_anylayout!(dest, src, f_x, z, (s_l, s_u), (d_l, d_u), m)
 
     dest

test/test_broadcasting.jl

@@ -99,6 +99,11 @@ import BandedMatrices: BandedStyle, BandedRows
         A .= B
         @test A == B
 
+        B = brand(1,4,0,1)
+        C = brand(size(B)...,0,0)
+        @test_throws BandError C .= B
+        @test_throws BandError C' .= B'
+
         @testset "empty dest" begin
             test_empty((D,B) -> D .= B)
         end