Disallow weird assignments

spec/compiler/parser/parser_spec.cr

@@ -276,6 +276,10 @@ module Crystal
     assert_syntax_error "a.b() += 1"
     assert_syntax_error "a.[]() += 1"
 
+    assert_syntax_error "a.[] 0 = 1"
+    assert_syntax_error "a.[] 0 += 1"
+    assert_syntax_error "a b: 0 = 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)
@@ -2821,5 +2825,29 @@ module Crystal
       node = Parser.parse(source).as(Annotation).path
       node_source(source, node).should eq("::Foo")
     end
+
+    it "sets correct location of call dot" do
+      parser = Parser.new("a.b")
+      node = parser.parse.as(Call)
+      dot_location = node.dot_location.not_nil!
+      dot_location.line_number.should eq(1)
+      dot_location.column_number.should eq(2)
+    end
+
+    it "sets correct location of call dot in assignment" do
+      parser = Parser.new("a.b = c")
+      node = parser.parse.as(Call)
+      dot_location = node.dot_location.not_nil!
+      dot_location.line_number.should eq(1)
+      dot_location.column_number.should eq(2)
+    end
+
+    it "sets correct location of call dot in operator assignment" do
+      parser = Parser.new("a.b += c")
+      node = parser.parse.as(OpAssign).target.as(Call)
+      dot_location = node.dot_location.not_nil!
+      dot_location.line_number.should eq(1)
+      dot_location.column_number.should eq(2)
+    end
   end
 end

spec/support/syntax.cr

@@ -133,8 +133,8 @@ class Crystal::ASTNode
   end
 end
 
-def assert_syntax_error(str, message = nil, line = nil, column = nil, metafile = __FILE__, metaline = __LINE__, metaendline = __END_LINE__)
-  it "says syntax error on #{str.inspect}", metafile, metaline, metaendline do
+def assert_syntax_error(str, message = nil, line = nil, column = nil, metafile = __FILE__, metaline = __LINE__, metaendline = __END_LINE__, *, focus : Bool = false)
+  it "says syntax error on #{str.inspect}", metafile, metaline, metaendline, focus: focus do
     begin
       parse str
       fail "Expected SyntaxException to be raised", metafile, metaline

src/compiler/crystal/syntax/ast.cr

@@ -647,6 +647,7 @@ module Crystal
     property block : Block?
     property block_arg : ASTNode?
     property named_args : Array(NamedArgument)?
+    property dot_location : Location?
     property name_location : Location?
     @name_size = -1
     property doc : String?

src/compiler/crystal/syntax/parser.cr

@@ -678,6 +678,8 @@ module Crystal
             break
           end
         when .op_period?
+          dot_location = @token.location
+
           check_void_value atomic, location
 
           @wants_regex = false
@@ -761,6 +763,7 @@ module Crystal
               end
 
               atomic = Call.new(atomic, "#{name}=", arg).at(location).at_end(end_location)
+              atomic.dot_location = dot_location
               atomic.name_location = name_location
               next
             when .assignment_operator?
@@ -769,6 +772,7 @@ module Crystal
               next_token_skip_space_or_newline
               value = parse_op_assign
               call = Call.new(atomic, name).at(location)
+              call.dot_location = dot_location
               call.name_location = name_location
               atomic = OpAssign.new(call, method, value).at(location)
               atomic.name_location = op_name_location
@@ -790,6 +794,7 @@ module Crystal
             block = parse_block(block, stop_on_do: @stop_on_do)
             atomic = Call.new atomic, name, (args || [] of ASTNode), block, block_arg, named_args
             atomic.has_parentheses = has_parentheses
+            atomic.dot_location = dot_location
             atomic.name_location = name_location
             atomic.end_location = block.try(&.end_location) || call_args.try(&.end_location) || end_location
             atomic.at(location)
@@ -6185,7 +6190,9 @@ module Crystal
       when Var, InstanceVar, ClassVar, Path, Global, Underscore
         true
       when Call
-        !node.has_parentheses? && ((node.obj.nil? && node.args.empty? && node.block.nil?) || node.name == "[]")
+        return false if node.has_parentheses?
+        return true if node.obj.nil? && node.args.empty? && node.named_args.nil? && node.block.nil?
+        node.name == "[]" && node.dot_location.nil?
       else
         false
       end