Disallow assignments to calls with parentheses (#14527)

spec/compiler/parser/parser_spec.cr

@@ -267,6 +267,15 @@ module Crystal
     assert_syntax_error "a.b(), c.d = 1"
     assert_syntax_error "a.b, c.d() = 1"
 
+    assert_syntax_error "a() = 1"
+    assert_syntax_error "a {} = 1"
+    assert_syntax_error "a.b() = 1"
+    assert_syntax_error "a.[]() = 1"
+    assert_syntax_error "a() += 1"
+    assert_syntax_error "a {} += 1"
+    assert_syntax_error "a.b() += 1"
+    assert_syntax_error "a.[]() += 1"
+
     it_parses "def foo\n1\nend", Def.new("foo", body: 1.int32)
     it_parses "def downto(n)\n1\nend", Def.new("downto", ["n".arg], 1.int32)
     it_parses "def foo ; 1 ; end", Def.new("foo", body: 1.int32)

src/compiler/crystal/syntax/parser.cr

@@ -376,6 +376,8 @@ module Crystal
           break
         when .op_eq?
           slash_is_regex!
+          break unless can_be_assigned?(atomic)
+
           if atomic.is_a?(Call) && atomic.name == "[]"
             next_token_skip_space_or_newline
 
@@ -385,8 +387,6 @@ module Crystal
             atomic.args << arg
             atomic.end_location = arg.end_location
           else
-            break unless can_be_assigned?(atomic)
-
             if atomic.is_a?(Path) && (inside_def? || inside_fun? || @is_constant_assignment)
               raise "dynamic constant assignment. Constants can only be declared at the top level or inside other types."
             end
@@ -6185,7 +6185,7 @@ module Crystal
       when Var, InstanceVar, ClassVar, Path, Global, Underscore
         true
       when Call
-        (node.obj.nil? && node.args.size == 0 && node.block.nil?) || node.name == "[]"
+        !node.has_parentheses? && ((node.obj.nil? && node.args.empty? && node.block.nil?) || node.name == "[]")
       else
         false
       end