diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..2ffbad6
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+debug
+Manifest.toml
diff --git a/src/infer.jl b/src/infer.jl
index 9edc3ba..e9f7223 100644
--- a/src/infer.jl
+++ b/src/infer.jl
@@ -182,70 +182,71 @@ function openbranches(bl)
 end
 
 function step!(inf::Inference)
-  frame, b, f, ip = pop!(inf.queue)
-  block, stmts = getblock(frame, b, f)
-  uninline!(frame, b, f)
-  if ip <= length(stmts)
-    var = stmts[ip]
-    st = block[var]
-    if isexpr(st.expr, :call)
-      T = infercall!(inf, (frame, b, f, ip), block, st.expr)
-      if T != Union{}
-        block.ir[var] = stmt(block[var], type = _union(st.type, T))
-        push!(inf.queue, (frame, b, f, ip+1))
-      end
-    elseif isexpr(st.expr, :inbounds)
-      push!(inf.queue, (frame, b, f, ip+1))
+    frame, b, f, ip = pop!(inf.queue)
+    block, stmts = getblock(frame, b, f)
+    uninline!(frame, b, f)
+    if ip <= length(stmts)
+        var = stmts[ip]
+        st = block[var]
+        st.expr isa QuoteNode && return
+        if isexpr(st.expr, :call)
+            T = infercall!(inf, (frame, b, f, ip), block, st.expr)
+            if T != Union{}
+                block.ir[var] = stmt(block[var], type = _union(st.type, T))
+                push!(inf.queue, (frame, b, f, ip+1))
+            end
+        elseif isexpr(st.expr, :inbounds)
+            push!(inf.queue, (frame, b, f, ip+1))
+        else
+            error("Unrecognised expression $(st.expr)")
+        end
+    elseif (brs = openbranches(block); length(brs) == 1 && !isreturn(brs[1])
+            && !(brs[1].block == length(frame.ir.blocks)))
+        inferbranch!(inf, frame, b, f, brs[1])
     else
-      error("Unrecognised expression $(st.expr)")
-    end
-  elseif (brs = openbranches(block); length(brs) == 1 && !isreturn(brs[1])
-          && !(brs[1].block == length(frame.ir.blocks)))
-    inferbranch!(inf, frame, b, f, brs[1])
-  else
-    for br in brs
-      if isreturn(br)
-        T = exprtype(block.ir, IRTools.returnvalue(block))
-        _issubtype(T, frame.rettype) && return
-        frame.rettype = _union(frame.rettype, T)
-        foreach(loc -> push!(inf.queue, loc), frame.edges)
-      else
-        args = exprtype.((block.ir,), arguments(br))
-        if blockargs!(IRTools.block(frame.ir, br.block), args)
-          push!(inf.queue, (frame, br.block, 0, 1))
+        for br in brs
+            if isreturn(br)
+                T = exprtype(block.ir, IRTools.returnvalue(block))
+                _issubtype(T, frame.rettype) && return
+                frame.rettype = _union(frame.rettype, T)
+                foreach(loc -> push!(inf.queue, loc), frame.edges)
+            else
+                args = exprtype.((block.ir,), arguments(br))
+                if blockargs!(IRTools.block(frame.ir, br.block), args)
+                    push!(inf.queue, (frame, br.block, 0, 1))
+                end
+            end
         end
-      end
     end
-  end
-  return
+    return
 end
 
 function infer!(inf::Inference)
-  while !isempty(inf.queue)
-    step!(inf)
-  end
-  for (_, fr) in inf.frames
-    inline_bbs!(fr)
-    fr.ir |> IRTools.Inner.trimblocks!
-  end
-  return inf
+    while !isempty(inf.queue)
+        step!(inf)
+    end
+    for (_, fr) in inf.frames
+        inline_bbs!(fr)
+        fr.ir |> IRTools.Inner.trimblocks!
+    end
+    return inf
 end
 
 function Inference(fr::Frame, P)
-  q = WorkQueue{Any}()
-  push!(q, (fr, 1, 0, 1))
-  Inference(Dict(argtypes(fr.ir)=>fr), q, IdDict(), P)
+    q = WorkQueue{Any}()
+    push!(q, (fr, 1, 0, 1))
+    Inference(Dict(argtypes(fr.ir)=>fr), q, IdDict(), P)
 end
 
 function infer!(P, ir::IR, args...)
-  fr = frame(ir, args...)
-  inf = Inference(fr, P)
-  infer!(inf)
+    fr = frame(ir, args...)
+    inf = Inference(fr, P)
+    infer!(inf)
 end
 
 function return_type(ir::IR, args...)
-  fr = frame(copy(ir), args...)
-  inf = Inference(fr, Defaults())
-  infer!(inf)
-  return fr.rettype
+    fr = frame(copy(ir), args...)
+    inf = Inference(fr, Defaults())
+    infer!(inf)
+    return fr.rettype
 end
diff --git a/src/lib/base.jl b/src/lib/base.jl
index 57b714c..d179713 100644
--- a/src/lib/base.jl
+++ b/src/lib/base.jl
@@ -52,5 +52,4 @@ struct KwFunc{F} end
 
 @abstract Basic Core.kwfunc(::T) where T = Const(KwFunc{T}())
 
-instead(::Basic, args, ::AType{KwFunc{F}}, kw, f, xs...) where F =
-  args, (Core.kwftype(widen(f)), kw, f, xs...)
+instead(::Basic, args, ::AType{KwFunc{F}}, kw, f, xs...) where F = (args, (Core.kwftype(widen(f)), kw, f, xs...))
diff --git a/src/lib/numeric.jl b/src/lib/numeric.jl
index 84c1e22..80a4eec 100644
--- a/src/lib/numeric.jl
+++ b/src/lib/numeric.jl
@@ -7,8 +7,7 @@ struct Numeric end
               asin, asind, asinh, atan, atand, atanh, cbrt, conj, cos, cosd, cosh,
               cospi, cot, cotd, coth, csc, cscd, csch, deg2rad, exp, exp10, exp2,
               expm1, float, inv, log, log10, log1p, log2, rad2deg, sec, secd, sech,
-              sin, sind, sinh, sinpi, sqrt, tan, tand, tanh, transpose, trailing_zeros,
-              >>, <<, unsigned, rem, //
+              sin, sind, sinh, sinpi, sqrt, tan, tand, tanh, transpose, trailing_zeros, >>, <<, unsigned, rem, //
 
 @abstract Numeric rand() = Float64
 @abstract Numeric randn() = Float64
@@ -16,3 +15,4 @@ struct Numeric end
 
 @abstract Numeric sum(xs::Array{T,N}; dims = :) where {T,N} =
   dims == Const(:) ? T : Array{T,N}
+
diff --git a/test/trace.jl b/test/trace.jl
index 85ef706..ce5d304 100644
--- a/test/trace.jl
+++ b/test/trace.jl
@@ -145,6 +145,15 @@ tr = @trace pow(2, 3)
 tr = @trace pow(::Int, ::Int)
 @test returntype(tr) == Int
 
+function m(n)
+    for i in 1 : n
+        nothing
+    end
+end
+
+tr = @trace m(::Int)
+@test returntype(tr) == Const(nothing)
+
 function sumabs2(xs)
   s = zero(eltype(xs))
   for i = 1:length(xs)