Added so JuliaLang#7714 also takes care of args... when considering a match and

removed the requirement of equal lengths of args. The match also takes
into account that parametric methods args needs to have the same type for
one tvar using typeintersect. There is also added test of
`show_method_candidates`.

Author: dhoegh

base/replutil.jl

@@ -167,28 +167,62 @@ function showerror(io::IO, e::MethodError)
         print(io, "This may have arisen from a call to the constructor $(e.args[1])(...), ")
         print(io, "since type constructors fall back to convert methods in julia v0.4.")
     end
+    
+    show_method_candidates(io, e)
+end
 
-    # Display up to three closest candidates
+function show_method_candidates(io::IO, e::MethodError)
+    # Displays the closest candidates of the given function by looping over the
+    # functions methods and counting the number of matching arguments.
     lines = Array((IOBuffer, Int), 0)
     for method in methods(e.f)
-        n = length(e.args)
-        if n != length(method.sig)
-            continue
-        end
         buf = IOBuffer()
-        print(buf, "  $(e.f.env.name)(")
-        first = true
+        print(buf, "  $(e.f.env.name)")
+        right_matches = 0
+        tv = method.tvars
+        if !isa(tv,Tuple)
+            tv = (tv,)
+        end
+        if !isempty(tv)
+            show_delim_array(buf, tv, '{', ',', '}', false)
+        end
+        print(buf, "(")
+        t_i = Any[typeof(e.args)...]
         right_matches = 0
-        for (arg, sigtype) in Zip2{Any,Any}(e.args, method.sig)
-            if first
-                first = false
+        for i = 1 : min(length(t_i), length(method.sig))
+            i != 1 && print(buf, ", ")
+            # If isvarargtype then it checks wether the rest of the input arguements matches
+            # the varargtype
+			j = Base.isvarargtype(method.sig[i]) ? length(t_i) : i
+            # checks if the type of arg 1:i of the input intersects with the current method
+            t_in = typeintersect(method.sig[1:i], tuple(t_i[1:j]...))
+            if t_in == None
+                # If there is no typeintersect then the type signature from the method is
+                # inserted in t_i this insures if the type at the next i matches the type
+                # signature then there will be a type intersect
+                t_i[i] = method.sig[i]
+                Base.with_output_color(:red, buf) do buf
+                    print(buf, "::$(method.sig[i])")
+                end
             else
-                print(buf, ", ")
+                right_matches += j==i ? 1 : 0
+                print(buf, "::$(method.sig[i])")
             end
-            if typeof(arg) <: sigtype
-                right_matches += 1
-                print(buf, "::$(sigtype)")
-            else
+        end
+        if length(t_i) > length(method.sig) && Base.isvarargtype(method.sig[end])
+            # It insures that methods like f(a::AbstractString...) gets the correct
+            # number of right_matches
+            for t in typeof(e.args)[length(method.sig):end]
+                if t <: method.sig[end].parameters[1]
+                    right_matches += 1
+                end
+            end
+        end
+        if length(t_i) < length(method.sig)
+            # If the methods args is longer than input then the method
+            # arguments is printed as not a match
+            for sigtype in method.sig[length(t_i)+1:end]
+                print(buf, ", ")
                 Base.with_output_color(:red, buf) do buf
                     print(buf, "::$(sigtype)")
                 end
@@ -199,7 +233,7 @@ function showerror(io::IO, e::MethodError)
             push!(lines, (buf, right_matches))
         end
     end
-    if length(lines) != 0
+    if length(lines) != 0 # Display up to three closest candidates
         Base.with_output_color(:normal, io) do io
             println(io, "\nClosest candidates are:")
             sort!(lines, by = x -> -x[2])

test/replutil.jl

@@ -0,0 +1,41 @@
+function test_have_color(buf, color, no_color)
+    if Base.have_color
+        @test takebuf_string(buf) == color
+    else
+        @test takebuf_string(buf) == no_color
+    end
+end
+let
+    f(x::Int, s::AbstractString...) = pass
+    buf = IOBuffer()
+    Base.show_method_candidates(buf, Base.MethodError(f,(1.,1,"")))
+    no_color = "Closest candidates are:\n  f(::Int64, ::AbstractString...)"
+    test_have_color(buf,
+                    "\e[0m\nClosest candidates are:\n  f(\e[1m\e[31m::Int64\e[0m, \e[1m\e[31m::AbstractString...\e[0m)\n\e[0m",
+                    no_color)
+
+    Base.show_method_candidates(buf, Base.MethodError(f,(1.,"","")))
+    test_have_color(buf,
+                    "\e[0m\nClosest candidates are:\n  f(\e[1m\e[31m::Int64\e[0m, ::AbstractString...)\n\e[0m",
+                    no_color)
+
+    # should match
+    Base.show_method_candidates(buf, Base.MethodError(f,(1,"","")))
+    test_have_color(buf,
+                    "\e[0m\nClosest candidates are:\n  f(::Int64, ::AbstractString...)\n\e[0m",
+                    no_color)
+
+    # Have no matches so should return empty
+    Base.show_method_candidates(buf, Base.MethodError(f,(1.,1,1)))
+    test_have_color(buf, "", "")
+
+    g(x::Int, args...) = pass
+    g(x::Int, y::Float64 ,args...) = pass
+    g(x::Int, y::Float64) = pass
+    g{T<:Real}(x::T, y::T, z::T) = pass
+    Base.show_method_candidates(buf, Base.MethodError(g,(1.,1.,2)))
+    color = "\e[0m\nClosest candidates are:\n  g(\e[1m\e[31m::Int64\e[0m, ::Float64, ::Any...)\n  g(\e[1m\e[31m::Int64\e[0m, ::Any...)\n  g{T<:Real}(::T<:Real, ::T<:Real, \e[1m\e[31m::T<:Real\e[0m)\n  ...\n\e[0m"
+    no_color = no_color = "Closest candidates are:\n  g(::Int64, ::Float64, ::Any...)\n  g(::Int64, ::Any...)\n  g{T<:Real}(::T<:Real, ::T<:Real, ::T<:Real)\n  ..."
+    test_have_color(buf, color, no_color)
+
+end

test/runtests.jl

@@ -9,7 +9,7 @@ testnames = [
     "resolve", "pollfd", "mpfr", "broadcast", "complex", "socket",
     "floatapprox", "readdlm", "reflection", "regex", "float16", "combinatorics",
     "sysinfo", "rounding", "ranges", "mod2pi", "euler", "show",
-    "lineedit", "replcompletions", "repl", "sets", "test", "goto",
+    "lineedit", "replcompletions", "repl", "replutil", "sets", "test", "goto",
     "llvmcall", "grisu", "nullable", "meta", "profile",
     "libgit2", "docs", "base64", "parser"
 ]