diff --git a/base/strings/unicode.jl b/base/strings/unicode.jl
index 5d59b0fc3bff4..d8f3a2b6ad66b 100644
--- a/base/strings/unicode.jl
+++ b/base/strings/unicode.jl
@@ -800,7 +800,7 @@ isgraphemebreak(c1::AbstractChar, c2::AbstractChar) =
 # Stateful grapheme break required by Unicode-9 rules: the string
 # must be processed in sequence, with state initialized to Ref{Int32}(0).
 # Requires utf8proc v2.0 or later.
-function isgraphemebreak!(state::Ref{Int32}, c1::AbstractChar, c2::AbstractChar)
+@inline function isgraphemebreak!(state::Ref{Int32}, c1::AbstractChar, c2::AbstractChar)
     if ismalformed(c1) || ismalformed(c2)
         state[] = 0
         return true
diff --git a/stdlib/Unicode/test/runtests.jl b/stdlib/Unicode/test/runtests.jl
index 7fa57508cffbf..2af7015afa249 100644
--- a/stdlib/Unicode/test/runtests.jl
+++ b/stdlib/Unicode/test/runtests.jl
@@ -284,6 +284,8 @@ end
     @test_throws BoundsError graphemes("äöüx", 2:5)
     @test_throws BoundsError graphemes("äöüx", 5:5)
     @test_throws ArgumentError graphemes("äöüx", 0:1)
+
+    @test @allocated(length(graphemes("äöüx"))) == 0
 end
 
 @testset "#3721, #6939 up-to-date character widths" begin