Extended printing at a MethodError.

base/replutil.jl

@@ -165,29 +165,68 @@ function showerror(io::IO, ex::MethodError)
         print(io, "since type constructors fall back to convert methods in julia v0.4.")
     end
 
-    # Display up to three closest candidates
+    show_method_candidates(io, ex)
+end
+
+function show_method_candidates(io::IO, ex::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)
+    name = isgeneric(ex.f) ? ex.f.env.name : :anonymous
     for method in methods(ex.f)
-        n = length(ex.args)
-        if n != length(method.sig)
-            continue
-        end
         buf = IOBuffer()
-        print(buf, "  $(ex.f.env.name)(")
-        first = true
+        print(buf, "  $name")
+        right_matches = 0
+        tv = method.tvars
+        if !isa(tv,Tuple)
+            tv = (tv,)
+        end
+        if !isempty(tv)
+            show_delim_array(buf, tv, '{', ',', '}', false)
+        end
+        print(buf, "(")
+        t_i = Any[typeof(ex.args)...]
         right_matches = 0
-        for (arg, sigtype) in Zip2{Any,Any}(ex.args, method.sig)
-            if first
-                first = false
+        for i = 1 : min(length(t_i), length(method.sig))
+            i != 1 && print(buf, ", ")
+            # If isvarargtype then it checks wether the rest of the input arguements matches
+            # the varargtype
+            j = Base.isvarargtype(method.sig[i]) ? length(t_i) : i
+            # checks if the type of arg 1:i of the input intersects with the current method
+            t_in = typeintersect(method.sig[1:i], tuple(t_i[1:j]...))
+            if t_in == None
+                if Base.have_color
+                    print(buf, "\e[1m\e[31m::$(method.sig[i])\e[0m")
+                else
+                    print(buf, "!Matched::$(method.sig[i])")
+                end
+                # If there is no typeintersect then the type signature from the method is
+                # inserted in t_i this ensures if the type at the next i matches the type
+                # signature then there will be a type intersect
+                t_i[i] = method.sig[i]
             else
-                print(buf, ", ")
+                right_matches += j==i ? 1 : 0
+                print(buf, "::$(method.sig[i])")
             end
-            if typeof(arg) <: sigtype
-                right_matches += 1
-                print(buf, "::$(sigtype)")
-            else
-                Base.with_output_color(:red, buf) do buf
-                    print(buf, "::$(sigtype)")
+        end
+        if length(t_i) > length(method.sig) && Base.isvarargtype(method.sig[end])
+            # It ensures that methods like f(a::AbstractString...) gets the correct
+            # number of right_matches
+            for t in typeof(ex.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, ", ")
+                if Base.have_color
+                    print(buf, "\e[1m\e[31m::$sigtype\e[0m")
+                else
+                    print(buf, "!Matched::$sigtype")
                 end
             end
         end
@@ -196,7 +235,7 @@ function showerror(io::IO, ex::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 +1,43 @@
+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
+
+method_c1(x::Float64, s::AbstractString...) = true
+
+buf = IOBuffer()
+Base.show_method_candidates(buf, Base.MethodError(method_c1,(1, 1, "")))
+no_color = "\nClosest candidates are:\n  method_c1(!Matched::Float64, !Matched::AbstractString...)\n"
+test_have_color(buf,
+                "\e[0m\nClosest candidates are:\n  method_c1(\e[1m\e[31m::Float64\e[0m, \e[1m\e[31m::AbstractString...\e[0m)\n\e[0m",
+                no_color)
+
+no_color = "\nClosest candidates are:\n  method_c1(!Matched::Float64, ::AbstractString...)\n"
+Base.show_method_candidates(buf, Base.MethodError(method_c1,(1, "", "")))
+test_have_color(buf,
+                "\e[0m\nClosest candidates are:\n  method_c1(\e[1m\e[31m::Float64\e[0m, ::AbstractString...)\n\e[0m",
+                no_color)
+
+# should match
+no_color = "\nClosest candidates are:\n  method_c1(::Float64, ::AbstractString...)\n"
+Base.show_method_candidates(buf, Base.MethodError(method_c1,(1., "", "")))
+test_have_color(buf,
+                "\e[0m\nClosest candidates are:\n  method_c1(::Float64, ::AbstractString...)\n\e[0m",
+                no_color)
+
+# Have no matches so should return empty
+Base.show_method_candidates(buf, Base.MethodError(method_c1,(1, 1, 1)))
+test_have_color(buf, "", "")
+
+method_c2(x::Int32, args...) = true
+method_c2(x::Int32, y::Float64 ,args...) = true
+method_c2(x::Int32, y::Float64) = true
+method_c2{T<:Real}(x::T, y::T, z::T) = true
+
+Base.show_method_candidates(buf, Base.MethodError(method_c2,(1., 1., 2)))
+color = "\e[0m\nClosest candidates are:\n  method_c2(\e[1m\e[31m::Int32\e[0m, ::Float64, ::Any...)\n  method_c2(\e[1m\e[31m::Int32\e[0m, ::Any...)\n  method_c2{T<:Real}(::T<:Real, ::T<:Real, \e[1m\e[31m::T<:Real\e[0m)\n  ...\n\e[0m"
+no_color = no_color = "\nClosest candidates are:\n  method_c2(!Matched::Int32, ::Float64, ::Any...)\n  method_c2(!Matched::Int32, ::Any...)\n  method_c2{T<:Real}(::T<:Real, ::T<:Real, !Matched::T<:Real)\n  ...\n"
+test_have_color(buf, color, no_color)

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"
 ]