test 2-arg show for various new types

Author: nsajko

test/no_invalidations.jl

@@ -51,6 +51,13 @@ function test_expr(f, supertype::Type)
 end
 
 @testset "no invalidations test set" begin
+    @testset "2-arg `show` for various new types" begin
+        stypes = (Integer, AbstractString, DenseVector{UInt8}, DenseMatrix{Float32}, AbstractUnitRange{Int})
+        broken = (AbstractString,)
+        @testset "S: $S" for S ∈ stypes
+            @test test_expr((n -> :(function Base.show(::IO, ::$n) end)), S) broken=(S ∈ broken)
+        end
+    end
     @testset "new subtype of `Integer`" begin
         int_types = (Bool, Int8, UInt8, Int16, UInt16, Int, UInt, BigInt)
         @testset "construction of old int type from new type" begin