diff --git a/Library/Homebrew/brew.rb b/Library/Homebrew/brew.rb
index aa38b54f4d..62cfd79c3e 100644
--- a/Library/Homebrew/brew.rb
+++ b/Library/Homebrew/brew.rb
@@ -23,8 +23,7 @@ end
 def require?(path)
   require path
 rescue LoadError => e
-  # HACK: ( because we should raise on syntax errors but
-  # not if the file doesn't exist. TODO make robust!
+  # we should raise on syntax errors but not if the file doesn't exist.
   raise unless e.to_s.include? path
 end
 
diff --git a/Library/Homebrew/dependable.rb b/Library/Homebrew/dependable.rb
index 0834b08eca..785eb94d8f 100644
--- a/Library/Homebrew/dependable.rb
+++ b/Library/Homebrew/dependable.rb
@@ -20,8 +20,6 @@ module Dependable
   end
 
   def required?
-    # FIXME: Should `required?` really imply `!build?`? And if so, why doesn't
-    #        any of `optional?` and `recommended?` equally imply `!build?`?
     !build? && !optional? && !recommended?
   end
 
diff --git a/Library/Homebrew/extend/ENV/std.rb b/Library/Homebrew/extend/ENV/std.rb
index 403ea19783..aafc0a4519 100644
--- a/Library/Homebrew/extend/ENV/std.rb
+++ b/Library/Homebrew/extend/ENV/std.rb
@@ -1,7 +1,6 @@
 require "hardware"
 require "extend/ENV/shared"
 
-# TODO: deprecate compiling related codes after it's only used by brew test.
 # @private
 module Stdenv
   include SharedEnvExtension
diff --git a/Library/Homebrew/extend/pathname.rb b/Library/Homebrew/extend/pathname.rb
index 690979e4ed..c413e9e94b 100644
--- a/Library/Homebrew/extend/pathname.rb
+++ b/Library/Homebrew/extend/pathname.rb
@@ -331,7 +331,6 @@ class Pathname
     raise ChecksumMismatchError.new(self, expected, actual) unless expected == actual
   end
 
-  # FIXME: eliminate the places where we rely on this method
   alias to_str to_s unless method_defined?(:to_str)
 
   def cd
diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index b32775c786..4ff5d3175f 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -1908,7 +1908,6 @@ class Formula
   def exec_cmd(cmd, args, out, logfn)
     ENV["HOMEBREW_CC_LOG_PATH"] = logfn
 
-    # TODO: system "xcodebuild" is deprecated, this should be removed soon.
     ENV.remove_cc_etc if cmd.to_s.start_with? "xcodebuild"
 
     # Turn on argument filtering in the superenv compiler wrapper.
diff --git a/Library/Homebrew/formula_installer.rb b/Library/Homebrew/formula_installer.rb
index 7fed4b24e8..2153e7671a 100644
--- a/Library/Homebrew/formula_installer.rb
+++ b/Library/Homebrew/formula_installer.rb
@@ -887,6 +887,6 @@ class FormulaInstaller
   def puts_requirement_messages
     return unless @requirement_messages
     return if @requirement_messages.empty?
-    puts @requirement_messages
+    $stderr.puts @requirement_messages
   end
 end
diff --git a/Library/Homebrew/global.rb b/Library/Homebrew/global.rb
index 05af5bb670..6505ca54e0 100644
--- a/Library/Homebrew/global.rb
+++ b/Library/Homebrew/global.rb
@@ -62,7 +62,6 @@ ORIGINAL_PATHS = ENV["HOMEBREW_PATH"].split(File::PATH_SEPARATOR).map do |p|
   end
 end.compact.freeze
 
-# TODO: remove this as soon as it's removed from commands.rb.
 HOMEBREW_INTERNAL_COMMAND_ALIASES = {
   "ls" => "list",
   "homepage" => "home",
diff --git a/Library/Homebrew/os/mac/xquartz.rb b/Library/Homebrew/os/mac/xquartz.rb
index b82772faf7..2fdf0abead 100644
--- a/Library/Homebrew/os/mac/xquartz.rb
+++ b/Library/Homebrew/os/mac/xquartz.rb
@@ -5,7 +5,6 @@ module OS
     module XQuartz
       module_function
 
-      # TODO: confirm this path when you have internet
       DEFAULT_BUNDLE_PATH = Pathname.new("Applications/Utilities/XQuartz.app").freeze
       FORGE_BUNDLE_ID = "org.macosforge.xquartz.X11".freeze
       APPLE_BUNDLE_ID = "org.x.X11".freeze
diff --git a/Library/Homebrew/test/cmd/install_spec.rb b/Library/Homebrew/test/cmd/install_spec.rb
index c1240a30e0..034bdd53f0 100644
--- a/Library/Homebrew/test/cmd/install_spec.rb
+++ b/Library/Homebrew/test/cmd/install_spec.rb
@@ -217,10 +217,9 @@ describe "brew install", :integration_test do
       depends_on NonFatalRequirement
     EOS
 
-    # FIXME: This should output to STDERR.
     expect { brew "install", "testball1" }
-      .to output(/NonFatalRequirement unsatisfied!/).to_stdout
-      .and not_to_output.to_stderr
+      .to output(/NonFatalRequirement unsatisfied!/).to_stderr
+      .and output(/built in/).to_stdout
       .and be_a_success
   end
 
@@ -234,10 +233,9 @@ describe "brew install", :integration_test do
       depends_on FatalRequirement
     EOS
 
-    # FIXME: This should output to STDERR.
     expect { brew "install", "testball1" }
-      .to output(/FatalRequirement unsatisfied!/).to_stdout
-      .and output(/An unsatisfied requirement failed this build./).to_stderr
+      .to output(/FatalRequirement unsatisfied!/).to_stderr
+      .and not_to_output.to_stdout
       .and be_a_failure
   end
 end
diff --git a/Library/Homebrew/utils/analytics.sh b/Library/Homebrew/utils/analytics.sh
index 35f91eabc0..8d5cf2ff73 100644
--- a/Library/Homebrew/utils/analytics.sh
+++ b/Library/Homebrew/utils/analytics.sh
@@ -85,8 +85,6 @@ report-analytics-screenview-command() {
   fi
 
   # Don't report commands used mostly by our scripts and not users.
-  # TODO: list more e.g. shell completion things here perhaps using a single
-  # script as a shell-completion entry point.
   case "$HOMEBREW_COMMAND" in
     --prefix|analytics|command|commands)
       return
diff --git a/bin/brew b/bin/brew
index 84be2fb1d7..1c7b4c8971 100755
--- a/bin/brew
+++ b/bin/brew
@@ -47,8 +47,7 @@ HOMEBREW_LIBRARY="$HOMEBREW_REPOSITORY/Library"
 for VAR in EDITOR PATH
 do
   VAR_NEW="HOMEBREW_${VAR}"
-  # TODO: find a better solution than this.
-  env | grep -q "$VAR_NEW" && continue
+  [[ -n "${!VAR_NEW}" ]] && continue
   export "$VAR_NEW"="${!VAR}"
 done