define occursin(needle, haystack), add method for Char needle

README.md

@@ -285,6 +285,8 @@ Currently, the `@compat` macro supports the following syntaxes:
 
 * `Compat.mv` and `Compat.cp` with `force` keyword argument ([#26069]).
 
+* `occursin(needle, haystack::AbstractString)` now has a method for `Char` needles ([#22435], [#26283]).
+
 ## Renaming
 
 * `Display` is now `AbstractDisplay` ([#24831]).
@@ -338,7 +340,10 @@ Currently, the `@compat` macro supports the following syntaxes:
 
 * `copy!` and `unsafe_copy!` are now `copyto!` and `unsafe_copyto!` ([#24808]).
 
-* `ismatch(r::Regex, str::AbstractString)` is now `contains(str, r)` ([#24673]).
+* `contains(haystack, needle)` is now `occursin(needle, haystack)` ([#26283]).
+
+* `ismatch(r::Regex, str::AbstractString, offset=0)` is now `occursin(r, str)` and
+  `occursin(r, str, offset = offset)` respectively ([#24673],[#26283]).
 
 * `ipermute!` is now `invpermute!` ([#25168]).
 
@@ -514,6 +519,7 @@ includes this fix. Find the minimum version from there.
 [#22064]: https://github.com/JuliaLang/julia/issues/22064
 [#22182]: https://github.com/JuliaLang/julia/issues/22182
 [#22350]: https://github.com/JuliaLang/julia/issues/22350
+[#22435]: https://github.com/JuliaLang/julia/issues/22435
 [#22475]: https://github.com/JuliaLang/julia/issues/22475
 [#22512]: https://github.com/JuliaLang/julia/issues/22512
 [#22629]: https://github.com/JuliaLang/julia/issues/22629
@@ -598,6 +604,7 @@ includes this fix. Find the minimum version from there.
 [#26089]: https://github.com/JuliaLang/julia/issues/26089
 [#26149]: https://github.com/JuliaLang/julia/issues/26149
 [#26156]: https://github.com/JuliaLang/julia/issues/26156
+[#26283]: https://github.com/JuliaLang/julia/issues/26283
 [#26316]: https://github.com/JuliaLang/julia/issues/26316
 [#26436]: https://github.com/JuliaLang/julia/issues/26436
 [#26442]: https://github.com/JuliaLang/julia/issues/26442

src/Compat.jl

@@ -901,6 +901,22 @@ end
     occursin(x) = in(x)
 end
 
+# PR#26283
+@static if VERSION < v"0.7.0-DEV.4639"
+    occursin(needle, haystack) = contains(haystack, needle)
+end
+@static if VERSION < v"0.7.0-DEV.4639"
+    @static if VERSION < v"0.7.0-DEV.3272"
+        occursin(r::Regex, s::AbstractString; offset::Integer = 0) = ismatch(r, s, offset)
+    else
+        occursin(r::Regex, s::AbstractString; offset::Integer = 0) = contains(s, r, offset)
+    end
+end
+
+# PR#22435
+@static if VERSION < v"0.7.0-DEV.702"
+    Base.contains(haystack::AbstractString, needle::Char) = searchindex(haystack,needle) != 0
+end
 
 # 0.7.0-DEV.912
 if VERSION < v"0.7.0-DEV.912"
@@ -1171,7 +1187,7 @@ end
     export copyto!, unsafe_copyto!
 end
 
-# 0.7.0-DEV.3272
+# 0.7.0-DEV.3272, keep this definition for 0.6 compatibility
 @static if VERSION < v"0.7.0-DEV.3272"
     Base.contains(str::AbstractString, r::Regex) = ismatch(r, str)
 end

test/runtests.jl

@@ -185,13 +185,13 @@ let filename = tempname()
         end
     end
     @test ret == [2]
-    @test contains(read(filename, String), "WARNING: hello")
+    @test occursin("WARNING: hello", read(filename, String))
     ret = open(filename) do f
         redirect_stdin(f) do
             readline()
         end
     end
-    @test contains(ret, "WARNING: hello")
+    @test occursin("WARNING: hello", ret)
     rm(filename)
 end
 
@@ -837,7 +837,7 @@ no_specialize_kw2(@nospecialize(x::Integer=0)) = sin(2)
 
 # 0.7
 @test read(IOBuffer("aaaa"), String) == "aaaa"
-@test contains(read(@__FILE__, String), "read(@__FILE__, String)")
+@test occursin("read(@__FILE__, String)", read(@__FILE__, String))
 @test read(`$(Base.julia_cmd()) --startup-file=no -e "println(:aaaa)"`, String) == "aaaa\n"
 
 # 0.7
@@ -1115,8 +1115,17 @@ end
 using Compat.Random
 @test rand(MersenneTwister(1234)) == 0.5908446386657102
 
-# 0.7
-@test contains("Hello, World!", r"World")
+# 0.7, make sure this works on 0.6
+if VERSION < v"0.7.0-DEV.3272"
+    @test contains("Hello, World!", r"World")
+end
+
+# 0.7.0-DEV.4639
+@test occursin(r"World", "Hello, World!")
+@test occursin(r"World", "Hello, World!", offset = 4)
+@test occursin("World", "Hello, World!")
+# 0.7.0-DEV.912
+@test occursin('W', "Hello, World!")
 
 # 0.7.0-DEV.3449
 let A = [2.0 1.0; 1.0 3.0], b = [1.0, 2.0], x = [0.2, 0.6]