diff --git a/lib/mutant/ast.rb b/lib/mutant/ast.rb
index 5936dec5..7dfd78fe 100644
--- a/lib/mutant/ast.rb
+++ b/lib/mutant/ast.rb
@@ -44,7 +44,7 @@ module Mutant
     # @api private
     #
     def self.find_last_path(node, &predicate)
-      raise ArgumentError, 'block expected' unless block_given?
+      fail ArgumentError, 'block expected' unless block_given?
       path = []
       walk(node, [node]) do |candidate, stack|
         if predicate.call(candidate, &predicate)
diff --git a/lib/mutant/context/scope.rb b/lib/mutant/context/scope.rb
index 22d23e5f..46e65e23 100644
--- a/lib/mutant/context/scope.rb
+++ b/lib/mutant/context/scope.rb
@@ -50,7 +50,7 @@ module Mutant
         when ::Module
           s(:module, name, node)
         else
-          raise "Cannot wrap scope: #{scope.inspect}"
+          fail "Cannot wrap scope: #{scope.inspect}"
         end
       end
 
diff --git a/lib/mutant/expression/method.rb b/lib/mutant/expression/method.rb
index 3d92bc2d..9e6ae908 100644
--- a/lib/mutant/expression/method.rb
+++ b/lib/mutant/expression/method.rb
@@ -25,7 +25,7 @@ module Mutant
         methods_matcher = MATCHERS.fetch(scope_symbol).new(env, scope)
         method = methods_matcher.methods.detect do |meth|
           meth.name.equal?(method_name)
-        end or raise NameError, "Cannot find method #{method_name}"
+        end or fail NameError, "Cannot find method #{method_name}"
         methods_matcher.matcher.build(env, scope, method)
       end
 
diff --git a/lib/mutant/meta/example/dsl.rb b/lib/mutant/meta/example/dsl.rb
index 63935e17..ca8cc339 100644
--- a/lib/mutant/meta/example/dsl.rb
+++ b/lib/mutant/meta/example/dsl.rb
@@ -40,7 +40,7 @@ module Mutant
         # @api private
         #
         def example
-          raise 'source not defined' unless @source
+          fail 'source not defined' unless @source
           Example.new(@file, @source, @expected)
         end
 
@@ -55,7 +55,7 @@ module Mutant
         # @api private
         #
         def source(input)
-          raise 'source already defined' if @source
+          fail 'source already defined' if @source
           @source = node(input)
 
           self
@@ -72,7 +72,7 @@ module Mutant
         def mutation(input)
           node = node(input)
           if @expected.include?(node)
-            raise "Node for input: #{input.inspect} is already expected"
+            fail "Node for input: #{input.inspect} is already expected"
           end
           @expected << node
 
@@ -108,7 +108,7 @@ module Mutant
           when Parser::AST::Node
             input
           else
-            raise "Cannot coerce to node: #{source.inspect}"
+            fail "Cannot coerce to node: #{source.inspect}"
           end
         end
 
diff --git a/lib/mutant/mutator/registry.rb b/lib/mutant/mutator/registry.rb
index 35cfb3f1..dfe96664 100644
--- a/lib/mutant/mutator/registry.rb
+++ b/lib/mutant/mutator/registry.rb
@@ -39,7 +39,7 @@ module Mutant
       def self.lookup(node)
         type = node.type
         registry.fetch(type) do
-          raise ArgumentError, "No mutator to handle: #{type.inspect}"
+          fail ArgumentError, "No mutator to handle: #{type.inspect}"
         end
       end
 
@@ -67,7 +67,7 @@ module Mutant
       #
       def self.assert_valid_type(type)
         unless AST::Types::ALL.include?(type) || type.is_a?(Class)
-          raise InvalidTypeError, "invalid type registration: #{type}"
+          fail InvalidTypeError, "invalid type registration: #{type}"
         end
       end
       private_class_method :assert_valid_type
@@ -83,7 +83,7 @@ module Mutant
       #
       def self.assert_unique_type(type)
         if registry.key?(type)
-          raise DuplicateTypeError, "duplicate type registration: #{type}"
+          fail DuplicateTypeError, "duplicate type registration: #{type}"
         end
       end
       private_class_method :assert_unique_type