diff --git a/Library/Homebrew/keg.rb b/Library/Homebrew/keg.rb
index dfc27b55a9..257594671a 100644
--- a/Library/Homebrew/keg.rb
+++ b/Library/Homebrew/keg.rb
@@ -1,7 +1,6 @@
 require "extend/pathname"
 require "keg_relocate"
 require "formula_lock"
-require "diagnostic"
 require "ostruct"
 
 class Keg
@@ -298,33 +297,14 @@ class Keg
   end
 
   def installed_dependents
-    installed_kegs = Formula.installed.flat_map(&:installed_kegs)
-    installed_kegs_and_tabs = installed_kegs.map { |k| [k, Tab.for_keg(k)] }
-    kegs_by_tab_deps_presence = installed_kegs_and_tabs.group_by do |_, tab|
-      !tab.runtime_dependencies.nil?
-    end
-    [true, false].each { |v| kegs_by_tab_deps_presence[v] ||= [] }
-
-    kegs_by_tab_deps_presence[true].select! do |_, tab|
-      tab.runtime_dependencies.any? do |dep|
+    Formula.installed.flat_map(&:installed_kegs).select do |keg|
+      Tab.for_keg(keg).runtime_dependencies.any? do |dep|
         # Resolve formula rather than directly comparing names
         # in case of conflicts between formulae from different taps.
         dep_formula = Formulary.factory(dep["full_name"])
         dep_formula == to_formula && dep["version"] == version.to_s
       end
     end
-
-    remaining_kegs_and_tabs = kegs_by_tab_deps_presence[false]
-    remaining_formulae = remaining_kegs_and_tabs.map { |k, _| k.to_formula }
-
-    # Expensive if installed_dependents of multiple kegs are being checked
-    deps = Homebrew::Diagnostic.missing_deps(remaining_formulae, [name])
-    remaining_kegs_and_tabs.select! do |keg, _|
-      keg_deps = deps[keg.to_formula.full_name]
-      keg_deps && keg_deps.any?
-    end
-
-    kegs_by_tab_deps_presence.values.flatten(1).map { |k, _| k }
   end
 
   def find(*args, &block)
diff --git a/Library/Homebrew/test/test_keg.rb b/Library/Homebrew/test/test_keg.rb
index 9c1c9118c9..ac5831b092 100644
--- a/Library/Homebrew/test/test_keg.rb
+++ b/Library/Homebrew/test/test_keg.rb
@@ -339,29 +339,8 @@ class InstalledDependantsTests < LinkTests
     tab.write
   end
 
-  def test_unknown_dependencies
-    dependencies nil
-
-    bar = formula "bar" do
-      url "bar-1.0"
-      depends_on "foo"
-    end
-    stub_formula_loader bar
-
-    assert_equal [@dependent], @keg.installed_dependents
-  end
-
   def test_no_dependencies
     dependencies []
-
-    # Make sure formula dependencies aren't checked when dependencies are
-    # recorded in the tab.
-    bar = formula "bar" do
-      url "bar-1.0"
-      depends_on "foo"
-    end
-    stub_formula_loader bar
-
     assert_empty @keg.installed_dependents
   end