Add Node#loc_is? for easier test of locations

lib/rubocop/ast/node.rb

@@ -497,7 +497,7 @@ def operator_keyword?
       end
 
       def parenthesized_call?
-        loc.respond_to?(:begin) && loc.begin&.is?('(')
+        loc_is?(:begin, '(')
       end
 
       def call_type?
@@ -534,6 +534,17 @@ def guard_clause?
         node.match_guard_clause?
       end
 
+      # Shortcut to safely test a particular location, even if
+      # this location does not exist or is `nil`
+      def loc_is?(which_loc, str)
+        return false unless loc.respond_to?(which_loc)
+
+        location = loc.public_send(which_loc)
+        return false unless location
+
+        location.is?(str)
+      end
+
       # @!method match_guard_clause?(node = self)
       def_node_matcher :match_guard_clause?, <<~PATTERN
         [${(send nil? {:raise :fail} ...) return break next} single_line?]

lib/rubocop/ast/node/array_node.rb

@@ -34,7 +34,7 @@ def each_value(&block)
       #
       # @return [Boolean] whether the array is enclosed in square brackets
       def square_brackets?
-        loc.begin&.is?('[')
+        loc_is?(:begin, '[')
       end
 
       # Checks whether the `array` literal is delimited by percent brackets.

lib/rubocop/ast/node/for_node.rb

@@ -17,7 +17,7 @@ def keyword
       #
       # @return [Boolean] whether the `for` node has a `do` keyword
       def do?
-        loc.begin&.is?('do')
+        loc_is?(:begin, 'do')
       end
 
       # Checks whether this node body is a void context.

lib/rubocop/ast/node/hash_node.rb

@@ -115,7 +115,7 @@ def mixed_delimiters?
       #
       # @return [Boolean] whether the `hash` literal is enclosed in braces
       def braces?
-        loc.end&.is?('}')
+        loc_is?(:end, '}')
       end
     end
   end

lib/rubocop/ast/node/in_pattern_node.rb

@@ -24,7 +24,7 @@ def branch_index
       #
       # @return [Boolean] whether the `in` node has a `then` keyword
       def then?
-        loc.begin&.is?('then')
+        loc_is?(:begin, 'then')
       end
 
       # Returns the body of the `in` node.

lib/rubocop/ast/node/mixin/method_dispatch_node.rb

@@ -117,23 +117,23 @@ def setter_method?
       #
       # @return [Boolean] whether the method was called with a connecting dot
       def dot?
-        loc.respond_to?(:dot) && loc.dot&.is?('.')
+        loc_is?(:dot, '.')
       end
 
       # Checks whether the dispatched method uses a double colon to connect the
       # receiver and the method name.
       #
       # @return [Boolean] whether the method was called with a connecting dot
       def double_colon?
-        loc.respond_to?(:dot) && loc.dot&.is?('::')
+        loc_is?(:dot, '::')
       end
 
       # Checks whether the dispatched method uses a safe navigation operator to
       # connect the receiver and the method name.
       #
       # @return [Boolean] whether the method was called with a connecting dot
       def safe_navigation?
-        loc.respond_to?(:dot) && loc.dot&.is?('&.')
+        loc_is?(:dot, '&.')
       end
 
       # Checks whether the *explicit* receiver of this method dispatch is

lib/rubocop/ast/node/mixin/parameterized_node.rb

@@ -13,7 +13,7 @@ module ParameterizedNode
       # @return [Boolean] whether this node's arguments are
       #                   wrapped in parentheses
       def parenthesized?
-        loc.end&.is?(')')
+        loc_is?(:end, ')')
       end
 
       # A shorthand for getting the first argument of the node.

lib/rubocop/ast/node/str_node.rb

@@ -9,7 +9,7 @@ class StrNode < Node
       include BasicLiteralNode
 
       def character_literal?
-        loc.respond_to?(:begin) && loc.begin&.is?('?')
+        loc_is?(:begin, '?')
       end
 
       def heredoc?

lib/rubocop/ast/node/until_node.rb

@@ -28,7 +28,7 @@ def inverse_keyword
       #
       # @return [Boolean] whether the `until` node has a `do` keyword
       def do?
-        loc.begin&.is?('do')
+        loc_is?(:begin, 'do')
       end
     end
   end

lib/rubocop/ast/node/when_node.rb

@@ -33,7 +33,7 @@ def branch_index
       #
       # @return [Boolean] whether the `when` node has a `then` keyword
       def then?
-        loc.begin&.is?('then')
+        loc_is?(:begin, 'then')
       end
 
       # Returns the body of the `when` node.

lib/rubocop/ast/node/while_node.rb

@@ -28,7 +28,7 @@ def inverse_keyword
       #
       # @return [Boolean] whether the `until` node has a `do` keyword
       def do?
-        loc.begin&.is?('do')
+        loc_is?(:begin, 'do')
       end
     end
   end

spec/rubocop/ast/node_spec.rb

@@ -1109,4 +1109,28 @@ class << expr
       end
     end
   end
+
+  describe '#loc_is?' do
+    let(:src) { '%i[>> sym << sym2]' }
+
+    context 'when loc exists' do
+      let(:src) { ':sym' }
+
+      it 'returns true when loc matches argument' do
+        expect(node).to be_loc_is(:begin, ':')
+      end
+
+      it 'returns false when loc does not match argument' do
+        expect(node).not_to be_loc_is(:begin, '!')
+      end
+    end
+
+    it 'returns false when requested loc is `nil`' do
+      expect(node).not_to be_loc_is(:begin, ':')
+    end
+
+    it 'returns false when requested loc does not exist' do
+      expect(node).not_to be_loc_is(:foo, ':')
+    end
+  end
 end