Refactor ternary handling in Style/RedundantParentheses rule

spec/ameba/rule/style/redundant_parentheses_spec.cr

@@ -55,16 +55,22 @@ module Ameba::Rule::Style
           rule.exclude_ternary = false
 
           expect_issue rule, <<-CRYSTAL
-            (foo > bar) ? true : false
-            # ^^^^^^^^^ error: Redundant parentheses
+            (foo.empty?) ? true : false
+            # ^^^^^^^^^^ error: Redundant parentheses
             CRYSTAL
 
           expect_no_issues subject, <<-CRYSTAL
             (foo && bar) ? true : false
-            CRYSTAL
-
-          expect_no_issues subject, <<-CRYSTAL
             (foo || bar) ? true : false
+            (foo = @foo) ? true : false
+            foo == 42 ? true : false
+            (foo = 42) ? true : false
+            (foo > 42) ? true : false
+            (foo >= 42) ? true : false
+            (3 >= foo >= 42) ? true : false
+            (3.in? 0..42) ? true : false
+            (yield 42) ? true : false
+            (foo rescue 42) ? true : false
             CRYSTAL
         end
       end

src/ameba/rule/style/redundant_parentheses.cr

@@ -22,35 +22,44 @@ module Ameba::Rule::Style
   # ```
   # Style/RedundantParentheses:
   #   Enabled: true
-  #   ExcludeTernary: true
+  #   ExcludeTernary: false
   #   ExcludeAssignments: false
   # ```
   class RedundantParentheses < Base
     properties do
       description "Disallows redundant parentheses around control expressions"
 
-      exclude_ternary true
+      exclude_ternary false
       exclude_assignments false
     end
 
     MSG = "Redundant parentheses"
 
+    protected def strip_parentheses?(node, in_ternary) : Bool
+      case node
+      when Crystal::BinaryOp, Crystal::ExceptionHandler
+        !in_ternary
+      when Crystal::Call
+        !in_ternary || node.has_parentheses? || node.args.empty?
+      when Crystal::Yield
+        !in_ternary || node.has_parentheses? || node.exps.empty?
+      when Crystal::Assign, Crystal::OpAssign, Crystal::MultiAssign
+        !in_ternary && !exclude_assignments
+      else
+        true
+      end
+    end
+
     def test(source, node : Crystal::If | Crystal::Unless | Crystal::Case | Crystal::While | Crystal::Until)
       is_ternary = node.is_a?(Crystal::If) && node.ternary?
 
-      return if exclude_ternary && is_ternary
+      return if is_ternary && exclude_ternary
 
       return unless (cond = node.cond).is_a?(Crystal::Expressions)
       return unless cond.keyword.paren?
 
       return unless exp = cond.single_expression?
-
-      case exp
-      when Crystal::BinaryOp
-        return if is_ternary
-      when Crystal::Assign, Crystal::OpAssign
-        return if exclude_assignments
-      end
+      return unless strip_parentheses?(exp, is_ternary)
 
       issue_for cond, MSG do |corrector|
         corrector.remove_trailing(cond, 1)