Allow calling #[]= with a block using method syntax (#14161)

spec/compiler/formatter/formatter_spec.cr

@@ -1999,6 +1999,13 @@ describe Crystal::Formatter do
   assert_format "foo.[] = 1"
   assert_format "foo.[1, 2] = 3"
 
+  %w(<= == >= != []= ===).each do |operator|
+    assert_format "1.#{operator} { 3 }"
+    assert_format "1.#{operator}() { 3 }"
+    assert_format "1.#{operator}(2) { 3 }"
+    assert_format "1.#{operator} do\nend"
+  end
+
   assert_format "@foo : Int32 # comment\n\ndef foo\nend"
   assert_format "getter foo # comment\n\ndef foo\nend"
   assert_format "getter foo : Int32 # comment\n\ndef foo\nend"

spec/compiler/parser/parser_spec.cr

@@ -290,8 +290,6 @@ module Crystal
     assert_syntax_error "def foo=(*args); end", "setter method 'foo=' cannot have more than one parameter"
     assert_syntax_error "def foo=(**kwargs); end", "setter method 'foo=' cannot have more than one parameter"
     assert_syntax_error "def foo=(&block); end", "setter method 'foo=' cannot have a block"
-    assert_syntax_error "f.[]= do |a| end", "setter method '[]=' cannot be called with a block"
-    assert_syntax_error "f.[]= { |bar| }", "setter method '[]=' cannot be called with a block"
 
     # #10397
     %w(<= >= == != []= ===).each do |operator|
@@ -630,10 +628,12 @@ module Crystal
       it_parses "->Foo.#{op}(Int32)", ProcPointer.new("Foo".path, op, ["Int32".path] of ASTNode)
     end
 
-    ["bar", "+", "-", "*", "/", "<", "<=", "==", ">", ">=", "%", "|", "&", "^", "**", "===", "=~", "!~"].each do |name|
+    ["bar", "+", "-", "*", "/", "<", "<=", "==", ">", ">=", "%", "|", "&", "^", "**", "===", "=~", "!=", "[]=", "!~"].each do |name|
       it_parses "foo.#{name}", Call.new("foo".call, name)
       it_parses "foo.#{name} 1, 2", Call.new("foo".call, name, 1.int32, 2.int32)
       it_parses "foo.#{name}(1, 2)", Call.new("foo".call, name, 1.int32, 2.int32)
+      it_parses "foo.#{name}(1, 2) { 3 }", Call.new("foo".call, name, args: [1.int32, 2.int32] of ASTNode, block: Block.new(body: 3.int32))
+      it_parses "foo.#{name} do end", Call.new("foo".call, name, block: Block.new)
     end
 
     ["+", "-", "*", "/", "//", "%", "|", "&", "^", "**", "<<", ">>", "&+", "&-", "&*"].each do |op|

src/compiler/crystal/syntax/parser.cr

@@ -788,12 +788,6 @@ module Crystal
             end
 
             block = parse_block(block, stop_on_do: @stop_on_do)
-            if block || block_arg
-              if name == "[]="
-                raise "setter method '[]=' cannot be called with a block"
-              end
-            end
-
             atomic = Call.new atomic, name, (args || [] of ASTNode), block, block_arg, named_args
             atomic.has_parentheses = has_parentheses
             atomic.name_location = name_location