Support "Functor-like" code_typed invocation

This allows you to call, e.g., `code_typed((Foo, Int, Int))` to query
the code for `(::Foo)(::Int, ::Int)`

Author: topolarity

base/reflection.jl

@@ -211,8 +211,32 @@ julia> code_typed(+, (Float64, Float64))
 1 ─ %1 = Base.add_float(x, y)::Float64
 └──      return %1
 ) => Float64
+
+julia> code_typed((typeof(-), Float64, Float64))
+1-element Vector{Any}:
+ CodeInfo(
+1 ─ %1 = Base.sub_float(x, y)::Float64
+└──      return %1
+) => Float64
+
+julia> code_typed((Type{Int}, UInt8))
+1-element Vector{Any}:
+ CodeInfo(
+1 ─ %1 = Core.zext_int(Core.Int64, x)::Int64
+└──      return %1
+) => Int64
+
+julia> code_typed((Base.Broadcast.Pick{2}, Tuple{Bool,Float64,Int64}))
+1-element Vector{Any}:
+ CodeInfo(
+1 ─ %1 = \$(Expr(:boundscheck, true))::Bool
+│   %2 = Base.getfield(args, 2, %1)::Float64
+└──      return %2
+) => Float64
 ```
 """
+function code_typed end
+
 function code_typed(@nospecialize(f), @nospecialize(types=default_tt(f)); kwargs...)
     if isa(f, Core.OpaqueClosure)
         return code_typed_opaque_closure(f, types; kwargs...)
@@ -221,6 +245,12 @@ function code_typed(@nospecialize(f), @nospecialize(types=default_tt(f)); kwargs
     return code_typed_by_type(tt; kwargs...)
 end
 
+# support 'functor'-like queries, such as `(::Foo)(::Int, ::Int)` via `code_typed((Foo, Int, Int))`
+function code_typed(@nospecialize(argtypes::Union{Tuple,Type{<:Tuple}}); kwargs...)
+    tt = to_tuple_type(argtypes)
+    return code_typed_by_type(tt; kwargs...)
+end
+
 # returns argument tuple type which is supposed to be used for `code_typed` and its family;
 # if there is a single method this functions returns the method argument signature,
 # otherwise returns `Tuple` that doesn't match with any signature