--- a/build/moz.configure/rust.configure
+++ b/build/moz.configure/rust.configure
@@ -12,17 +12,17 @@ def rust_compiler_names(value):
         return ['rustc']
 
 @depends('--enable-rust')
 def cargo_binary_names(value):
     if value:
         return ['cargo']
 
 rustc = check_prog('RUSTC', rust_compiler_names, allow_missing=True)
-cargo = check_prog('CARGO', cargo_binary_names, allow_missing=True)
+cargo = check_prog('CARGO', cargo_binary_names, allow_missing=False)
 
 @depends_if(rustc)
 @checking('rustc version', lambda info: info.version)
 def rustc_info(rustc):
         out = check_cmd_output(rustc, '--version', '--verbose').splitlines()
         info = dict((s.strip() for s in line.split(':', 1)) for line in out[1:])
         return namespace(
             version=Version(info.get('release', '0')),