diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8137c197..4c95fbbe 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@
 * Nested keys are properly handled when generating messages hash (issue #489) (flash-gordon + solnic)
 * Result objects support `locale` and `full` options now (solnic)
 * Ability to configure `top_namespace` for messages, which will be used for both schema and rule localization (solnic)
+* Rule blocks receive a context object that you can use to share data between rules (solnic)
 
 ### Changed
 
diff --git a/lib/dry/validation/contract.rb b/lib/dry/validation/contract.rb
index 4db83e7d..5346ee7d 100644
--- a/lib/dry/validation/contract.rb
+++ b/lib/dry/validation/contract.rb
@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require 'concurrent/map'
+
 require 'dry/equalizer'
 require 'dry/initializer'
 
@@ -86,10 +88,12 @@ class Contract
       # @api public
       def call(input)
         Result.new(schema.(input), locale: locale) do |result|
+          context = Concurrent::Map.new
+
           rules.each do |rule|
             next if rule.keys.any? { |key| result.error?(key) }
 
-            rule.(self, result).failures.each do |failure|
+            rule.(self, result, context).failures.each do |failure|
               result.add_error(message_resolver[failure])
             end
           end
diff --git a/lib/dry/validation/evaluator.rb b/lib/dry/validation/evaluator.rb
index 21626e28..23e91298 100644
--- a/lib/dry/validation/evaluator.rb
+++ b/lib/dry/validation/evaluator.rb
@@ -54,16 +54,21 @@ def failure(message, tokens = EMPTY_HASH)
         end
       end
 
-      # @!attribute [r] _context
+      # @!attribute [r] _contract
       #   @return [Contract]
       #   @api private
-      param :_context
+      param :_contract
 
       # @!attribute [r] keys
       #   @return [Array<String, Symbol, Hash>]
       #   @api private
       option :keys
 
+      # @!attribute [r] _context
+      #   @return [Concurrent::Map]
+      #   @api public
+      option :_context
+
       # @!attribute [r] path
       #   @return [Dry::Schema::Path]
       #   @api private
@@ -79,7 +84,7 @@ def failure(message, tokens = EMPTY_HASH)
       # @api private
       def initialize(*args, &block)
         super(*args)
-        instance_eval(&block)
+        instance_exec(_context, &block)
       end
 
       # Get failures object for the default or provided path
@@ -120,18 +125,18 @@ def failures
 
       # @api private
       def respond_to_missing?(meth, include_private = false)
-        super || _context.respond_to?(meth, true)
+        super || _contract.respond_to?(meth, true)
       end
 
       private
 
-      # Forward to the underlying context
+      # Forward to the underlying contract
       #
       # @api private
       def method_missing(meth, *args, &block)
         # yes, we do want to delegate to private methods too
-        if _context.respond_to?(meth, true)
-          _context.__send__(meth, *args, &block)
+        if _contract.respond_to?(meth, true)
+          _contract.__send__(meth, *args, &block)
         else
           super
         end
diff --git a/lib/dry/validation/result.rb b/lib/dry/validation/result.rb
index 9684a71b..4259c529 100644
--- a/lib/dry/validation/result.rb
+++ b/lib/dry/validation/result.rb
@@ -94,25 +94,7 @@ def add_error(error)
       #
       # @api public
       def [](key)
-        if values.key?(key)
-          values[key]
-        elsif storage.key?(key)
-          storage[key]
-        end
-      end
-
-      # Store value under specified key
-      #
-      # @param [Symbol] key
-      # @param [Object] value
-      #
-      # @return [Object]
-      #
-      # @api public
-      def []=(key, value)
-        raise ArgumentError, "Key +#{key}+ was already set" if key?(key)
-
-        storage[key] = value
+        values[key]
       end
 
       # Check if a key was set
@@ -123,7 +105,7 @@ def []=(key, value)
       #
       # @api public
       def key?(key)
-        values.key?(key) || storage.key?(key)
+        values.key?(key)
       end
 
       # Coerce to a hash
@@ -159,11 +141,6 @@ def initialize_errors(options = self.options)
       def schema_errors(options)
         values.message_set(options).to_a
       end
-
-      # @api private
-      def storage
-        @storage ||= EMPTY_HASH.dup
-      end
     end
   end
 end
diff --git a/lib/dry/validation/rule.rb b/lib/dry/validation/rule.rb
index 435e9a4b..6763b4ed 100644
--- a/lib/dry/validation/rule.rb
+++ b/lib/dry/validation/rule.rb
@@ -25,12 +25,13 @@ class Rule
 
       # Evaluate the rule within the provided context
       #
-      # @param [Contract] context
-      # @param [Object] values
+      # @param [Contract] contract
+      # @param [Result] result
+      # @param [Concurrent::Map] context
       #
       # @api private
-      def call(context, values)
-        Evaluator.new(context, values: values, keys: keys, &block)
+      def call(contract, result, context)
+        Evaluator.new(contract, values: result, keys: keys, _context: context, &block)
       end
     end
   end
diff --git a/spec/integration/contract/evaluator/setting_values_spec.rb b/spec/integration/contract/evaluator/using_context_spec.rb
similarity index 51%
rename from spec/integration/contract/evaluator/setting_values_spec.rb
rename to spec/integration/contract/evaluator/using_context_spec.rb
index 1c0a4785..d5d97757 100644
--- a/spec/integration/contract/evaluator/setting_values_spec.rb
+++ b/spec/integration/contract/evaluator/using_context_spec.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-RSpec.describe Dry::Validation::Evaluator, 'values writer' do
+RSpec.describe Dry::Validation::Evaluator, 'using context' do
   context 'when key does not exist' do
     subject(:contract) do
       Dry::Validation::Contract.build do
@@ -9,16 +9,16 @@
           required(:user_id).filled(:integer)
         end
 
-        rule(:user_id) do
+        rule(:user_id) do |ctx|
           if values[:user_id].equal?(312)
-            values[:user] = 'jane'
+            ctx[:user] = 'jane'
           else
             key(:user).failure('must be jane')
           end
         end
 
-        rule(:email) do
-          key.failure('is invalid') if values[:user] == 'jane' && values[:email] != 'jane@doe.org'
+        rule(:email) do |ctx|
+          key.failure('is invalid') if ctx[:user] == 'jane' && values[:email] != 'jane@doe.org'
         end
       end
     end
@@ -28,22 +28,4 @@
       expect(contract.(user_id: 312, email: 'john@doe.org').errors.to_h).to eql(email: ['is invalid'])
     end
   end
-
-  context 'when key already exists' do
-    subject(:contract) do
-      Dry::Validation::Contract.build do
-        schema do
-          required(:email).filled(:string)
-        end
-
-        rule(:email) do
-          values[:email] = 'foo'
-        end
-      end
-    end
-
-    it 'raises error' do
-      expect { contract.(email: 'jane@doe.org') }.to raise_error(ArgumentError, /email/)
-    end
-  end
 end
diff --git a/spec/integration/evaluator_spec.rb b/spec/integration/evaluator_spec.rb
index 4e0c23f0..e2eee3fc 100644
--- a/spec/integration/evaluator_spec.rb
+++ b/spec/integration/evaluator_spec.rb
@@ -4,15 +4,15 @@
 
 RSpec.describe Dry::Validation::Evaluator do
   subject(:evaluator) do
-    Dry::Validation::Evaluator.new(context, options, &block)
+    Dry::Validation::Evaluator.new(contract, options, &block)
   end
 
-  let(:context) do
-    double(:context)
+  let(:contract) do
+    double(:contract)
   end
 
   let(:options) do
-    { keys: [:email], values: values }
+    { keys: [:email], values: values, _context: {} }
   end
 
   let(:values) do
@@ -26,23 +26,23 @@
       }
     end
 
-    it 'delegates to the context' do
-      expect(context).to receive(:works?).and_return(true)
+    it 'delegates to the contract' do
+      expect(contract).to receive(:works?).and_return(true)
       expect(evaluator.failures[0][:path].to_a).to eql([:email])
       expect(evaluator.failures[0][:message]).to eql('it works')
     end
 
-    describe 'with custom methods defined on the context' do
-      let(:context) do
-        double(context: :my_context)
+    describe 'with custom methods defined on the contract' do
+      let(:contract) do
+        double(contract: :my_contract)
       end
 
       let(:block) do
-        proc { key.failure("message with #{context}") }
+        proc { key.failure("message with #{contract}") }
       end
 
-      it 'forwards to the context' do
-        expect(evaluator.failures[0][:message]).to eql('message with my_context')
+      it 'forwards to the contract' do
+        expect(evaluator.failures[0][:message]).to eql('message with my_contract')
       end
     end
   end
diff --git a/spec/integration/result_spec.rb b/spec/integration/result_spec.rb
index ec860adf..bfc2767b 100644
--- a/spec/integration/result_spec.rb
+++ b/spec/integration/result_spec.rb
@@ -15,18 +15,6 @@
     end
   end
 
-  describe '#[]' do
-    let(:params) do
-      double(:params, message_set: [], to_h: {}, key?: false)
-    end
-
-    it 'returns nil for missing values' do
-      Dry::Validation::Result.new(params) do |r|
-        expect(r[:missing]).to be nil
-      end
-    end
-  end
-
   describe '#errors' do
     subject(:errors) { result.errors }