diff --git a/.gitignore b/.gitignore
index 0c89a967..6e5cdbe6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,3 +9,4 @@ deps/build.log
 deps/deps.jl
 Manifest.toml
 dev/
+test/tmpplotsave.hdf5
diff --git a/.travis.yml b/.travis.yml
index b8ae53eb..a4ca0ed6 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,7 +5,7 @@ os:
   # - osx
 julia:
   - 1
-  - 1.3
+  - 1.4
   - nightly
 
 matrix:
@@ -32,7 +32,10 @@ before_install:
 notifications:
   email: true
 
+after_success:
+  - julia -e 'using Pkg; Pkg.add("Coverage"); using Coverage; Codecov.submit(process_folder())'
+
 script:
   - if [[ -a .git/shallow ]]; then git fetch --unshallow; fi
   - if [[ `uname` = "Linux" ]]; then TESTCMD="xvfb-run julia"; else TESTCMD="julia"; fi
-  - $TESTCMD -e 'using Pkg; Pkg.pin(PackageSpec(name="FixedPointNumbers", version="0.7")); Pkg.build(); Pkg.test(coverage=true)'
+  - $TESTCMD -e 'using Pkg; if VERSION == v"1.4"; Pkg.resolve(); end; Pkg.pin(PackageSpec(name="FixedPointNumbers", version="0.7")); Pkg.build(); Pkg.test(coverage=true)'
diff --git a/Project.toml b/Project.toml
index f03c1ed2..26d82018 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "Plots"
 uuid = "91a5bcdd-55d7-5caf-9e0b-520d859cae80"
 author = ["Tom Breloff (@tbreloff)"]
-version = "0.29.8"
+version = "0.29.9"
 
 [deps]
 Base64 = "2a0f44e3-6c83-55bd-87e4-b1978d98bd5f"
diff --git a/README.md b/README.md
index 3c57fef1..ae3a3dd9 100644
--- a/README.md
+++ b/README.md
@@ -20,6 +20,7 @@
 [![][pkgeval-img]][pkgeval-url]
 [![][gitter-img]][gitter-url]
 [![][docs-img]][docs-url]
+[![Codecov](https://codecov.io/gh/JuliaPlots/Plots.jl/branch/master/graph/badge.svg)](https://codecov.io/gh/JuliaPlots/Plots.jl)
 
 #### Created by Tom Breloff (@tbreloff)
 
diff --git a/appveyor.yml b/appveyor.yml
index 890f4960..7742efb2 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -2,7 +2,7 @@ environment:
   matrix:
   # - julia_version: 0.7
   - julia_version: 1
-  - julia_version: 1.3
+  - julia_version: 1.4
   - julia_version: nightly
 
 platform:
@@ -33,10 +33,10 @@ install:
   - ps: iex ((new-object net.webclient).DownloadString("https://raw.githubusercontent.com/JuliaCI/Appveyor.jl/version-1/bin/install.ps1"))
 
 build_script:
-  - C:\julia\bin\julia --project=C:\projects\plots-jl -e "using Pkg; Pkg.pin(PackageSpec(name="""FixedPointNumbers""", version="""0.7"""))"
+  - C:\julia\bin\julia --project=C:\projects\plots-jl -e "using Pkg;  if VERSION == v"""1.4"""; Pkg.resolve(); end; Pkg.pin(PackageSpec(name="""FixedPointNumbers""", version="""0.7"""))"
   - echo "%JL_BUILD_SCRIPT%"
   - C:\julia\bin\julia -e "%JL_BUILD_SCRIPT%"
- 
+
 test_script:
   - echo "%JL_TEST_SCRIPT%"
   - C:\julia\bin\julia -e "%JL_TEST_SCRIPT%"
diff --git a/codecov.yml b/codecov.yml
new file mode 100644
index 00000000..79baa3c2
--- /dev/null
+++ b/codecov.yml
@@ -0,0 +1,10 @@
+ignore:
+  - "src/backends/inspectdr.jl"
+  - "src/backends/orca.jl"
+  - "src/backends/pgfplots.jl"
+  - "src/backends/plotly.jl"
+  - "src/backends/plotlyjs.jl"
+  - "src/backends/pyplot.jl"
+  - "src/backends/web.jl"
+  - "src/fileio.jl"
+  - "src/ijulia.jl"
diff --git a/src/args.jl b/src/args.jl
index 82ca09d8..cebc5344 100644
--- a/src/args.jl
+++ b/src/args.jl
@@ -460,6 +460,29 @@ is_axis_attr_noletter(k) = haskey(_axis_defaults, k)
 
 RecipesBase.is_key_supported(k::Symbol) = is_attr_supported(k)
 
+const _internal_args =
+    [:plot_object, :series_plotindex, :markershape_to_add, :letter, :idxfilter]
+const _magic_axis_args = [:axis, :tickfont, :guidefont]
+const _magic_subplot_args = [:titlefont, :legendfont, :legendtitlefont, ]
+const _magic_series_args = [:line, :marker, :fill]
+
+function is_noletter_attribute(k)
+    is_axis_attr_noletter(k) && return true
+    k in _magic_axis_args && return true
+    return false
+end
+
+function is_default_attribute(k)
+    k in _internal_args && return true
+    k in _all_args && return true
+    is_axis_attr(k) && return true
+    is_noletter_attribute(k) && return true
+    k in _magic_subplot_args && return true
+    k in _magic_series_args && return true
+    Symbol(chop(string(k); head = 1, tail = 0)) in _magic_axis_args && return true
+    return false
+end
+
 # -----------------------------------------------------------------------------
 
 makeplural(s::Symbol) = Symbol(string(s,"s"))
@@ -1017,6 +1040,16 @@ function preprocessArgs!(plotattributes::AKW)
             end
         end
     end
+    # handle axes guides
+    if haskey(plotattributes, :guide)
+        guide = pop!(plotattributes, :guide)
+        for letter in (:x, :y, :z)
+            guide_sym = Symbol(letter, :guide)
+            if !is_explicit(plotattributes, guide_sym)
+                plotattributes[guide_sym] = guide
+            end
+        end
+    end
 
     # handle line args
     for arg in wraptuple(pop_kw!(plotattributes, :line, ()))
diff --git a/src/pipeline.jl b/src/pipeline.jl
index 1e9cd991..ef846dd1 100644
--- a/src/pipeline.jl
+++ b/src/pipeline.jl
@@ -1,4 +1,26 @@
+# Error for aliases used in recipes
+function warn_on_recipe_aliases!(plotattributes, recipe_type, args...)
+    for k in keys(plotattributes)
+        if !is_default_attribute(k)
+            dk = get(_keyAliases, k, k)
+            if k !== dk
+                @warn "Attribute alias `$k` detected in the $recipe_type recipe defined for the signature $(signature_string(Val{recipe_type}, args...)). To ensure expected behavior it is recommended to use the default attribute `$dk`."
+            end
+            plotattributes[dk] = pop_kw!(plotattributes, k)
+        end
+    end
+end
+warn_on_recipe_aliases!(v::AbstractVector, recipe_type, args) =
+    foreach(x -> warn_on_recipe_aliases!(x, recipe_type, args), v)
+warn_on_recipe_aliases!(rd::RecipeData, recipe_type, args) =
+    warn_on_recipe_aliases!(rd.plotattributes, recipe_type, args)
 
+function signature_string(::Type{Val{:user}}, args...)
+    return string("(::", join(string.(typeof.(args)), ", ::"), ")")
+end
+signature_string(::Type{Val{:type}}, T) = "(::Type{$T}, ::$T)"
+signature_string(::Type{Val{:plot}}, st) = "(::Type{Val{:$st}}, ::AbstractPlot)"
+signature_string(::Type{Val{:series}}, st) = "(::Type{Val{:$st}}, x, y, z)"
 
 # ------------------------------------------------------------------
 # preprocessing
@@ -82,7 +104,11 @@ function _process_userrecipes(plt::Plot, plotattributes::AKW, args)
         if isempty(next_series.args)
             _process_userrecipe(plt, kw_list, next_series)
         else
-            rd_list = RecipesBase.apply_recipe(next_series.plotattributes, next_series.args...)
+            rd_list = RecipesBase.apply_recipe(
+                next_series.plotattributes,
+                next_series.args...
+            )
+            warn_on_recipe_aliases!(rd_list, :user, next_series.args)
             prepend!(still_to_process,rd_list)
         end
     end
@@ -184,6 +210,7 @@ function _process_plotrecipe(plt::Plot, kw::AKW, kw_list::Vector{KW}, still_to_p
         st = kw[:seriestype]
         st = kw[:seriestype] = get(_typeAliases, st, st)
         datalist = RecipesBase.apply_recipe(kw, Val{st}, plt)
+        warn_on_recipe_aliases!(datalist, :plot, st)
         for data in datalist
             preprocessArgs!(data.plotattributes)
             if data.plotattributes[:seriestype] == st
@@ -408,7 +435,9 @@ function _process_seriesrecipe(plt::Plot, plotattributes::AKW)
 
     else
         # get a sub list of series for this seriestype
-        datalist = RecipesBase.apply_recipe(plotattributes, Val{st}, plotattributes[:x], plotattributes[:y], plotattributes[:z])
+        x, y, z = plotattributes[:x], plotattributes[:y], plotattributes[:z]
+        datalist = RecipesBase.apply_recipe(plotattributes, Val{st}, x, y, z)
+        warn_on_recipe_aliases!(datalist, :series, st)
 
         # assuming there was no error, recursively apply the series recipes
         for data in datalist
diff --git a/src/recipes.jl b/src/recipes.jl
index dc94c1a9..79b4176d 100644
--- a/src/recipes.jl
+++ b/src/recipes.jl
@@ -1261,8 +1261,8 @@ end
     yflip := true
     aspect_ratio := 1
     rs, cs, zs = findnz(z.surf)
-    xlim := ignorenan_extrema(cs)
-    ylim := ignorenan_extrema(rs)
+    xlims := ignorenan_extrema(cs)
+    ylims := ignorenan_extrema(rs)
     if plotattributes[:markershape] == :none
         markershape := :circle
     end
diff --git a/src/series.jl b/src/series.jl
index 2773b221..bbb49469 100644
--- a/src/series.jl
+++ b/src/series.jl
@@ -20,6 +20,7 @@ function prepareSeriesData(a::AbstractArray{<:MaybeNumber})
     f = isimmutable(a) ? replace : replace!
     a = f(x -> ismissing(x) || isinf(x) ? NaN : x, map(float, a))
 end
+prepareSeriesData(a::AbstractArray{<:Missing}) = fill(NaN, axes(a))
 prepareSeriesData(a::AbstractArray{<:MaybeString}) = replace(x -> ismissing(x) ? "" : x, a)
 prepareSeriesData(s::Surface{<:AMat{<:MaybeNumber}}) = Surface(prepareSeriesData(s.surf))
 prepareSeriesData(s::Surface) = s  # non-numeric Surface, such as an image
@@ -171,9 +172,10 @@ end
 @recipe f(::Type{V}, x, y, z) where {V<:Val} = error("The backend must not support the series type $V, and there isn't a series recipe defined.")
 
 function _apply_type_recipe(plotattributes, v, letter)
-    _handle_axis_args!(plotattributes)
+    _preprocess_axis_args!(plotattributes, letter)
     rdvec = RecipesBase.apply_recipe(plotattributes, typeof(v), v)
-    _handle_axis_args!(plotattributes, letter)
+    warn_on_recipe_aliases!(plotattributes, :type, typeof(v))
+    _postprocess_axis_args!(plotattributes, letter)
     return rdvec[1].args[1]
 end
 
@@ -181,15 +183,17 @@ end
 # This sort of recipe should return a pair of functions... one to convert to number,
 # and one to format tick values.
 function _apply_type_recipe(plotattributes, v::AbstractArray, letter)
-    _handle_axis_args!(plotattributes)
+    _preprocess_axis_args!(plotattributes, letter)
     # First we try to apply an array type recipe.
     w = RecipesBase.apply_recipe(plotattributes, typeof(v), v)[1].args[1]
+    warn_on_recipe_aliases!(plotattributes, :type, typeof(v))
     # If the type did not change try it element-wise
     if typeof(v) == typeof(w)
         isempty(skipmissing(v)) && return Float64[]
         x = first(skipmissing(v))
         args = RecipesBase.apply_recipe(plotattributes, typeof(x), x)[1].args
-        _handle_axis_args!(plotattributes, letter)
+        warn_on_recipe_aliases!(plotattributes, :type, typeof(x))
+        _postprocess_axis_args!(plotattributes, letter)
         if length(args) == 2 && all(arg -> arg isa Function, args)
             numfunc, formatter = args
              return Formatted(map(numfunc, v), formatter)
@@ -197,7 +201,7 @@ function _apply_type_recipe(plotattributes, v::AbstractArray, letter)
              return v
         end
     end
-    _handle_axis_args!(plotattributes, letter)
+    _postprocess_axis_args!(plotattributes, letter)
     return w
 end
 
@@ -218,29 +222,32 @@ end
 # end
 
 # don't do anything for ints or floats
-_apply_type_recipe(plotattributes, v::AbstractArray{T}, letter) where {T<:Union{Integer,AbstractFloat}} = v
+_apply_type_recipe(plotattributes, v::AbstractArray{<:DataPoint}, letter) = v
 
-# axis args in type recipes should only be applied to the current axis
-function _handle_axis_args!(plotattributes, letter)
-    if letter in (:x, :y, :z)
-        replaceAliases!(plotattributes, _keyAliases)
-        for (k, v) in plotattributes
-            if haskey(_axis_defaults, k)
-                pop!(plotattributes, k)
-                lk = Symbol(letter, k)
+# axis args before type recipes should still be mapped to all axes
+function _preprocess_axis_args!(plotattributes)
+    for (k, v) in plotattributes
+        if is_noletter_attribute(k)
+            pop!(plotattributes, k)
+            for l in (:x, :y, :z)
+                lk = Symbol(l, k)
                 haskey(plotattributes, lk) || (plotattributes[lk] = v)
             end
         end
     end
 end
+function _preprocess_axis_args!(plotattributes, letter)
+    plotattributes[:letter] = letter
+    _preprocess_axis_args!(plotattributes)
+end
 
-# axis args before type recipes should still be mapped to all axes
-function _handle_axis_args!(plotattributes)
-    replaceAliases!(plotattributes, _keyAliases)
-    for (k, v) in plotattributes
-        if haskey(_axis_defaults, k)
-            pop!(plotattributes, k)
-            for letter in (:x, :y, :z)
+# axis args in type recipes should only be applied to the current axis
+function _postprocess_axis_args!(plotattributes, letter)
+    pop!(plotattributes, :letter)
+    if letter in (:x, :y, :z)
+        for (k, v) in plotattributes
+            if is_noletter_attribute(k)
+                pop!(plotattributes, k)
                 lk = Symbol(letter, k)
                 haskey(plotattributes, lk) || (plotattributes[lk] = v)
             end
diff --git a/src/types.jl b/src/types.jl
index 4ee8e9e0..a866e59f 100644
--- a/src/types.jl
+++ b/src/types.jl
@@ -26,8 +26,9 @@ struct Attr <: AbstractDict{Symbol,Any}
     defaults::KW
 end
 
-Base.getindex(attr::Attr, k) = haskey(attr.explicit,k) ?
-                                     attr.explicit[k] : attr.defaults[k]
+function Base.getindex(attr::Attr, k)
+    return haskey(attr.explicit, k) ? attr.explicit[k] : attr.defaults[k]
+end
 Base.haskey(attr::Attr, k) = haskey(attr.explicit,k) || haskey(attr.defaults,k)
 Base.get(attr::Attr, k, default) = haskey(attr, k) ? attr[k] : default
 function Base.get!(attr::Attr, k, default)
@@ -41,7 +42,7 @@ end
 function Base.delete!(attr::Attr, k)
     haskey(attr.explicit, k) && delete!(attr.explicit, k)
     haskey(attr.defaults, k) && delete!(attr.defaults, k)
-end 
+end
 Base.length(attr::Attr) = length(union(keys(attr.explicit), keys(attr.defaults)))
 function Base.iterate(attr::Attr)
     exp_keys = keys(attr.explicit)
diff --git a/src/backends/template.jl b/templates/backends.jl
similarity index 100%
rename from src/backends/template.jl
rename to templates/backends.jl