fix some cases of typeinfo printing (#33290)

Author: JeffBezanson

base/arrayshow.jl

@@ -457,6 +457,17 @@ typeinfo_eltype(typeinfo::Type{<:AbstractArray{T}}) where {T} = eltype(typeinfo)
 typeinfo_eltype(typeinfo::Type{<:AbstractDict{K,V}}) where {K,V} = eltype(typeinfo)
 typeinfo_eltype(typeinfo::Type{<:AbstractSet{T}}) where {T} = eltype(typeinfo)
 
+# types that can be parsed back accurately from their un-decorated representations
+function typeinfo_implicit(@nospecialize(T))
+    if T === Float64 || T === Int || T === Char || T === String || T === Symbol ||
+        issingletontype(T)
+        return true
+    end
+    return isconcretetype(T) &&
+        ((T <: Array && typeinfo_implicit(eltype(T))) ||
+         ((T <: Tuple || T <: Pair) && all(typeinfo_implicit, fieldtypes(T))) ||
+         (T <: AbstractDict && typeinfo_implicit(keytype(T)) && typeinfo_implicit(valtype(T))))
+end
 
 # X not constrained, can be any iterable (cf. show_vector)
 function typeinfo_prefix(io::IO, X)
@@ -470,14 +481,14 @@ function typeinfo_prefix(io::IO, X)
     eltype_X = eltype(X)
 
     if X isa AbstractDict
-        if eltype_X == eltype_ctx || !isempty(X) && isconcretetype(keytype(X)) && isconcretetype(valtype(X))
+        if eltype_X == eltype_ctx || (!isempty(X) && typeinfo_implicit(keytype(X)) && typeinfo_implicit(valtype(X)))
             string(typeof(X).name)
         else
             string(typeof(X))
         end
     else
         # Types hard-coded here are those which are created by default for a given syntax
-        if eltype_X == eltype_ctx || !isempty(X) && eltype_X in (Float64, Int, Char, String)
+        if eltype_X == eltype_ctx || (!isempty(X) && typeinfo_implicit(eltype_X))
             ""
         elseif print_without_params(eltype_X)
             string(unwrap_unionall(eltype_X).name) # Print "Array" rather than "Array{T,N}"

test/core.jl

@@ -1447,7 +1447,7 @@ struct Foo2509; foo::Int; end
 # issue #2517
 struct Foo2517; end
 @test repr(Foo2517()) == "$(curmod_prefix)Foo2517()"
-@test repr(Vector{Foo2517}(undef, 1)) == "$(curmod_prefix)Foo2517[$(curmod_prefix)Foo2517()]"
+@test repr(Vector{Foo2517}(undef, 1)) == "[$(curmod_prefix)Foo2517()]"
 @test Foo2517() === Foo2517()
 
 # issue #1474

test/missing.jl

@@ -221,7 +221,7 @@ end
 @testset "printing" begin
     @test sprint(show, missing) == "missing"
     @test sprint(show, missing, context=:compact => true) == "missing"
-    @test sprint(show, [missing]) == "$Missing[missing]"
+    @test sprint(show, [missing]) == "[missing]"
     @test sprint(show, [1 missing]) == "$(Union{Int, Missing})[1 missing]"
     b = IOBuffer()
     display(TextDisplay(b), [missing])

test/show.jl

@@ -787,8 +787,8 @@ let x = [], y = [], z = Base.ImmutableDict(x => y)
     push!(x, y)
     push!(y, x)
     push!(y, z)
-    @test replstr(x) == "1-element Array{Any,1}:\n Any[Any[Any[#= circular reference @-2 =#]], Base.ImmutableDict([Any[#= circular reference @-3 =#]] => [#= circular reference @-2 =#])]"
-    @test repr(z) == "Base.ImmutableDict([Any[Any[#= circular reference @-2 =#], Base.ImmutableDict(#= circular reference @-3 =#)]] => [Any[Any[#= circular reference @-2 =#]], Base.ImmutableDict(#= circular reference @-2 =#)])"
+    @test replstr(x) == "1-element Array{Any,1}:\n Any[Any[Any[#= circular reference @-2 =#]], Base.ImmutableDict{Array{Any,1},Array{Any,1}}([Any[#= circular reference @-3 =#]] => [#= circular reference @-2 =#])]"
+    @test repr(z) == "Base.ImmutableDict{Array{Any,1},Array{Any,1}}([Any[Any[#= circular reference @-2 =#], Base.ImmutableDict{Array{Any,1},Array{Any,1}}(#= circular reference @-3 =#)]] => [Any[Any[#= circular reference @-2 =#]], Base.ImmutableDict{Array{Any,1},Array{Any,1}}(#= circular reference @-2 =#)])"
     @test sprint(dump, x) == """
         Array{Any}((1,))
           1: Array{Any}((2,))
@@ -1058,7 +1058,7 @@ end
 
     # issue #28327
     d = Dict(Pair{Integer,Integer}(1,2)=>Pair{Integer,Integer}(1,2))
-    @test showstr(d) == "Dict((1 => 2) => (1 => 2))" # correct parenthesis
+    @test showstr(d) == "Dict{Pair{Integer,Integer},Pair{Integer,Integer}}((1 => 2) => (1 => 2))" # correct parenthesis
 
     # issue #29536
     d = Dict((+)=>1)
@@ -1263,8 +1263,8 @@ end
 
     # issue #27680
     @test replstr(Set([(1.0,1.0), (2.0,2.0), (3.0, 3.0)])) == (sizeof(Int) == 8 ?
-              "Set(Tuple{Float64,Float64}[(3.0, 3.0), (2.0, 2.0), (1.0, 1.0)])" :
-              "Set(Tuple{Float64,Float64}[(1.0, 1.0), (2.0, 2.0), (3.0, 3.0)])")
+              "Set([(3.0, 3.0), (2.0, 2.0), (1.0, 1.0)])" :
+              "Set([(1.0, 1.0), (2.0, 2.0), (3.0, 3.0)])")
 
     # issue #27747
     let t = (x = Integer[1, 2],)
@@ -1287,6 +1287,8 @@ end
     @test showstr(Pair{Integer,Integer}(1, 2), :typeinfo => Pair{Integer,Integer}) == "1 => 2"
     @test showstr([Pair{Integer,Integer}(1, 2)]) == "Pair{Integer,Integer}[1 => 2]"
     @test showstr(Dict{Integer,Integer}(1 => 2)) == "Dict{Integer,Integer}(1 => 2)"
+    @test showstr(Dict(true=>false)) == "Dict{Bool,Bool}(1 => 0)"
+    @test showstr(Dict((1 => 2) => (3 => 4))) == "Dict((1 => 2) => (3 => 4))"
 
     # issue #27979 (dislaying arrays of pairs containing arrays as first member)
     @test replstr([[1.0]=>1.0]) == "1-element Array{Pair{Array{Float64,1},Float64},1}:\n [1.0] => 1.0"
@@ -1551,7 +1553,7 @@ Z = Array{Float64}(undef,0,0)
     vec_undefined = Vector(undef, 2)
     vec_initialisers = fill(undef, 2)
     @test showstr(vec_undefined) == "Any[#undef, #undef]"
-    @test showstr(vec_initialisers) == "UndefInitializer[$undef, $undef]"
+    @test showstr(vec_initialisers) == "[$undef, $undef]"
     @test replstr(vec_undefined) == "2-element Array{Any,1}:\n #undef\n #undef"
     @test replstr(vec_initialisers) == "2-element Array{UndefInitializer,1}:\n $undef\n $undef"
 end