diff --git a/src/interface.jl b/src/interface.jl
index b99e7e6..55cf8e0 100644
--- a/src/interface.jl
+++ b/src/interface.jl
@@ -88,17 +88,17 @@ const essential_filters = [no_filters; [StaticLint.MissingReference, StaticLint.
 
 
 # Return (line, column) for a given offset in a source
-function convert_offset_to_line_from_filename(offset::Int64, filename::String)
+function convert_offset_to_line_from_filename(offset::Int, filename::String)
     all_lines = open(io->readlines(io), filename)
     return convert_offset_to_line_from_lines(offset, all_lines)
 end
 
-function convert_offset_to_line(offset::Int64, source::String)
+function convert_offset_to_line(offset::Int, source::String)
     return convert_offset_to_line_from_lines(offset, split(source, "\n"))
 end
 
 
-function convert_offset_to_line_from_lines(offset::Int64, all_lines)
+function convert_offset_to_line_from_lines(offset::Int, all_lines)
     offset < 0 && throw(BoundsError("source", offset))
 
     current_index = 1
diff --git a/src/linting/checks.jl b/src/linting/checks.jl
index 7654deb..1713140 100644
--- a/src/linting/checks.jl
+++ b/src/linting/checks.jl
@@ -134,7 +134,7 @@ function check_all(x::EXPR, opts::LintOptions, env::ExternalEnv, markers::Dict{S
     check_const(x)
 
     if opts.extended
-        for T in all_extended_rule_types
+        for T in all_extended_rule_types[]
             check(T(), x, markers)
         end
     end
diff --git a/src/linting/extended_checks.jl b/src/linting/extended_checks.jl
index aa7fe7a..5b34e1e 100644
--- a/src/linting/extended_checks.jl
+++ b/src/linting/extended_checks.jl
@@ -53,8 +53,11 @@ struct ReentrantLock_Extension <: ExtendedRule end
 struct SpinLock_Extension <: ExtendedRule end
 struct Lock_Extension <: ExtendedRule end
 struct Unlock_Extension <: ExtendedRule end
+struct Yield_Extension <: ExtendedRule end
+struct Sleep_Extension <: ExtendedRule end
+struct Mmap_Extension <: ExtendedRule end
 
-const all_extended_rule_types = InteractiveUtils.subtypes(ExtendedRule)
+const all_extended_rule_types = Ref{Any}(InteractiveUtils.subtypes(ExtendedRule))
 
 # template -> EXPR to be compared
 const check_cache = Dict{String, CSTParser.EXPR}()
@@ -65,6 +68,7 @@ const error_msgs = Dict{String, String}()
 function reset_static_lint_caches()
     empty!(check_cache)
     empty!(error_msgs)
+    all_extended_rule_types[] = InteractiveUtils.subtypes(ExtendedRule)
     return nothing
 end
 
@@ -128,3 +132,10 @@ function check(::Lock_Extension, x::EXPR)
 end
 
 check(::Unlock_Extension, x::EXPR) = generic_check(x, "unlock(hole_variable)", "`unlock` should be used with extreme caution.")
+check(::Yield_Extension, x::EXPR) = generic_check(x, "yield()", "`yield` should be used with extreme caution.")
+check(::Sleep_Extension, x::EXPR) = generic_check(x, "sleep(hole_variable)", "`sleep` should be used with extreme caution.")
+function check(::Mmap_Extension, x::EXPR)
+    generic_check(x, "mmap(hole_variable_star)", "`mmap` should be used with extreme caution.")
+    generic_check(x, "Mmap.mmap(hole_variable_star)", "`mmap` should be used with extreme caution.")
+end
+
diff --git a/test/rai_rules_tests.jl b/test/rai_rules_tests.jl
index ef8292c..b452220 100644
--- a/test/rai_rules_tests.jl
+++ b/test/rai_rules_tests.jl
@@ -372,6 +372,35 @@ end
         @test lint_test(source,
             "Line 15, column 9: `unlock` should be used with extreme caution.")
     end
+
+    @testset "yield, sleep, map" begin
+        source = """
+            function wait_for_cooldown(count::UInt64, counts::HistogramCounts)
+                while count != @atomic counts.total_observations
+                    yield()
+                    sleep(0.011)
+                end
+            end
+
+            function use_of_map()
+                s = open("/tmp/mmap.bin")
+                m = read(s, Int)
+                n = read(s, Int)
+                A2 = mmap(s, Matrix{Int}, (m,n))
+                A3 = Mmap.mmap(s, Matrix{Int}, (m,n))
+
+            end
+            """
+        @test lint_has_error_test(source)
+        @test lint_test(source,
+            "Line 3, column 9: `yield` should be used with extreme caution.")
+        @test lint_test(source,
+            "Line 4, column 9: `sleep` should be used with extreme caution.")
+        @test lint_test(source,
+            "Line 12, column 10: `mmap` should be used with extreme caution.")
+        @test lint_test(source,
+            "Line 13, column 10: `mmap` should be used with extreme caution.")
+    end
 end
 
 @testset "Comparison" begin