Print inspected values in dependency collector errors

Library/Homebrew/dependency_collector.rb

@@ -60,7 +60,7 @@ class DependencyCollector
     when Class
       parse_class_spec(spec, tags)
     else
-      raise TypeError, "Unsupported type #{spec.class} for #{spec}"
+      raise TypeError, "Unsupported type #{spec.class} for #{spec.inspect}"
     end
   end
 
@@ -103,7 +103,7 @@ class DependencyCollector
     # Tiger's ld is too old to properly link some software
     when :ld64       then LD64Dependency.new if MacOS.version < :leopard
     else
-      raise "Unsupported special dependency #{spec}"
+      raise "Unsupported special dependency #{spec.inspect}"
     end
   end
 
@@ -111,7 +111,7 @@ class DependencyCollector
     if spec < Requirement
       spec.new(tags)
     else
-      raise TypeError, "#{spec} is not a Requirement subclass"
+      raise TypeError, "#{spec.inspect} is not a Requirement subclass"
     end
   end