diff --git a/Library/Homebrew/cmd/--cache.rb b/Library/Homebrew/cmd/--cache.rb
index fef83fafad..79137eb298 100644
--- a/Library/Homebrew/cmd/--cache.rb
+++ b/Library/Homebrew/cmd/--cache.rb
@@ -17,7 +17,7 @@ module Homebrew
         description <<~EOS
           Display Homebrew's download cache. See also `HOMEBREW_CACHE`.
 
-          If <formula> is provided, display the file or directory used to cache <formula>.
+          If a <formula> or <cask> is provided, display the file or directory used to cache it.
         EOS
         flag   "--os=",
                description: "Show cache file for the given operating system. " \
@@ -113,7 +113,11 @@ module Homebrew
 
           puts bottle.cached_download
         elsif args.HEAD?
-          puts T.must(formula.head).cached_download
+          if (head = formula.head)
+            puts head.cached_download
+          else
+            opoo "No head is defined for #{formula.full_name}."
+          end
         else
           puts formula.cached_download
         end
diff --git a/docs/Manpage.md b/docs/Manpage.md
index f510f84d85..99ca5e54d2 100644
--- a/docs/Manpage.md
+++ b/docs/Manpage.md
@@ -1494,8 +1494,8 @@ dependency for their stable builds.
 
 Display Homebrew's download cache. See also `HOMEBREW_CACHE`.
 
-If *`formula`* is provided, display the file or directory used to cache
-*`formula`*.
+If a *`formula`* or *`cask`* is provided, display the file or directory used to
+cache it.
 
 `--os`
 
diff --git a/manpages/brew.1 b/manpages/brew.1
index 99f75ff08d..b75bd29081 100644
--- a/manpages/brew.1
+++ b/manpages/brew.1
@@ -938,7 +938,7 @@ Include only casks\.
 .SS "\fB\-\-cache\fP \fR[\fIoptions\fP] \fR[\fIformula\fP|\fIcask\fP \.\.\.]"
 Display Homebrew\[u2019]s download cache\. See also \fBHOMEBREW_CACHE\fP\&\.
 .P
-If \fIformula\fP is provided, display the file or directory used to cache \fIformula\fP\&\.
+If a \fIformula\fP or \fIcask\fP is provided, display the file or directory used to cache it\.
 .TP
 \fB\-\-os\fP
 Show cache file for the given operating system\. (Pass \fBall\fP to show cache files for all operating systems\.)