Type-stabilize eachline

Author: pabloferz

base/io.jl

@@ -558,11 +558,11 @@ removed. When called with a file name, the file is opened once at the beginning
 iteration and closed at the end. If iteration is interrupted, the file will be
 closed when the `EachLine` object is garbage collected.
 """
-eachline(stream::IO=STDIN; chomp::Bool=true) = EachLine(stream, chomp=chomp)
+eachline(stream::IO=STDIN; chomp::Bool=true) = EachLine(stream, chomp=chomp)::EachLine
 
 function eachline(filename::AbstractString; chomp::Bool=true)
     s = open(filename)
-    EachLine(s, ondone=()->close(s), chomp=chomp)
+    EachLine(s, ondone=()->close(s), chomp=chomp)::EachLine
 end
 
 start(itr::EachLine) = nothing

base/process.jl

@@ -562,7 +562,7 @@ function eachline(cmd::AbstractCmd, stdin; chomp::Bool=true)
     out = stdout.out
     # implicitly close after reading lines, since we opened
     return EachLine(out, chomp=chomp,
-        ondone=()->(close(out); success(processes) || pipeline_error(processes)))
+        ondone=()->(close(out); success(processes) || pipeline_error(processes)))::EachLine
 end
 eachline(cmd::AbstractCmd; chomp::Bool=true) = eachline(cmd, DevNull, chomp=chomp)
 

test/read.jl

@@ -252,7 +252,7 @@ for (name, f) in l
         @test collect(eachline(io(), chomp=false)) == collect(eachline(IOBuffer(text), chomp=false))
         @test collect(eachline(io(), chomp=false)) == collect(eachline(filename, chomp=false))
         @test collect(eachline(io())) == collect(eachline(IOBuffer(text)))
-        @test collect(eachline(io())) == collect(eachline(filename))
+        @test collect(@inferred(eachline(io()))) == collect(@inferred(eachline(filename))) #20351
 
         cleanup()