Merge pull request #1341 from smangelsdorf/symbol-proc-crash

[Fix #1340] Handle call with no receiver correctly in Style/SymbolProc cop

CHANGELOG.md

@@ -7,6 +7,7 @@
 * [#1326](https://github.com/bbatsov/rubocop/issues/1326): Fix problem in `SpaceInsideParens` with detecting space inside parentheses used for grouping expressions. ([@jonas054][])
 * [#1335](https://github.com/bbatsov/rubocop/issues/1335): Restrict URI schemes permitted by `LineLength` when `AllowURI` is enabled. ([@smangelsdorf][])
 * [#1339](https://github.com/bbatsov/rubocop/issues/1339): Handle `eql?` and `equal?` in `OpMethod`. ([@bbatsov][])
+* [#1340](https://github.com/bbatsov/rubocop/issues/1340): Fix crash in `Style/SymbolProc` cop when the block calls a method with no explicit receiver. ([@smangelsdorf][])
 
 ## 0.26.0 (03/09/2014)
 

lib/rubocop/cop/style/symbol_proc.rb

@@ -24,21 +24,9 @@ def on_block(node)
           return if ignored_method?(bmethod_name)
           # File.open(file) { |f| f.readlines }
           return if bargs
-          # something { |x, y| ... }
-          return unless block_args.children.size == 1
-          return unless block_body && block_body.type == :send
-
-          receiver, method_name, args = *block_body
-
-          # method in block must be invoked on a lvar without args
-          return if args
-          return if receiver.type != :lvar
-
-          block_arg_name, = *block_args.children.first
-          receiver_name, = *receiver
-
-          return if block_arg_name != receiver_name
+          return unless can_shorten?(block_args, block_body)
 
+          _receiver, method_name, _args = *block_body
           add_offense(node,
                       :expression,
                       format(MSG,
@@ -65,6 +53,23 @@ def ignored_methods
         def ignored_method?(name)
           ignored_methods.include?(name.to_s)
         end
+
+        def can_shorten?(block_args, block_body)
+          # something { |x, y| ... }
+          return false unless block_args.children.size == 1
+          return false unless block_body && block_body.type == :send
+
+          receiver, _method_name, args = *block_body
+
+          # method in block must be invoked on a lvar without args
+          return false if args
+          return false unless receiver && receiver.type == :lvar
+
+          block_arg_name, = *block_args.children.first
+          receiver_name, = *receiver
+
+          block_arg_name == receiver_name
+        end
       end
     end
   end

spec/rubocop/cop/style/symbol_proc_spec.rb

@@ -73,4 +73,9 @@
     corrected = autocorrect_source(cop, ['coll.map { |s| s.upcase }'])
     expect(corrected).to eq 'coll.map(&:upcase)'
   end
+
+  it 'does not crash with a bare method call' do
+    run = -> { inspect_source(cop, ['coll.map { |s| bare_method }']) }
+    expect(&run).not_to raise_error
+  end
 end