Fix parsing of (x && <y/>)

(x && <y/>) is reporting E0026 (missing operand for operator) between
'&&' and '<'. This is because we only parse JSX if the precedence allows
binary operators. This requirement is a mistake; we should parse JSX
regardless of the precedence. Fix the requirement, fixing the false
positive.

Author: strager

docs/CHANGELOG.md

@@ -6,6 +6,13 @@ based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 quick-lint-js' version numbers are arbitrary. quick-lint-js does *not* adhere to
 Semantic Versioning.
 
+## Unreleased
+
+### Fixed
+
+* `x && <Element/>` no longer falsely reports [E0026][] (missing operand for
+  operator). (Thanks to [Piotr Dąbrowski][] for reporting.)
+
 ## 2.1.0 (2022-02-09)
 
 [Downloads](https://c.quick-lint-js.com/releases/2.1.0/)
@@ -392,6 +399,7 @@ Beta release.
 [Lee Wannacott]: https://github.com/LeeWannacott
 [Matheus de Sousa]: https://github.com/keyehzy
 [Nico Sonack]: https://github.com/herrhotzenplotz
+[Piotr Dąbrowski]: https://github.com/yhnavein
 [Shivam Mehta]: https://github.com/maniac-en
 [coc.nvim]: https://github.com/neoclide/coc.nvim
 [config-global-groups]: https://quick-lint-js.com/config/#global-groups
@@ -404,6 +412,7 @@ Beta release.
 [E0016]: https://quick-lint-js.com/errors/E0016/
 [E0019]: https://quick-lint-js.com/errors/E0019/
 [E0020]: https://quick-lint-js.com/errors/E0020/
+[E0026]: https://quick-lint-js.com/errors/E0026/
 [E0036]: https://quick-lint-js.com/errors/E0036/
 [E0038]: https://quick-lint-js.com/errors/E0038/
 [E0040]: https://quick-lint-js.com/errors/E0040/

src/quick-lint-js/parse-expression-inl.h

@@ -611,16 +611,15 @@ expression* parser::parse_primary_expression(Visitor& v, precedence prec) {
         return function;
       }
     }
+    if (this->peek().type == token_type::less) {
+      // <MyComponent /> (JSX)
+      return this->parse_jsx_expression(v);
+    }
     expression* ast =
         this->make_expression<expression::_missing>(this->peek().span());
     if (prec.binary_operators) {
-      if (this->peek().type == token_type::less) {
-        // <MyComponent /> (JSX)
-        return this->parse_jsx_expression(v);
-      } else {
-        this->error_reporter_->report(
-            error_missing_operand_for_operator{this->peek().span()});
-      }
+      this->error_reporter_->report(
+          error_missing_operand_for_operator{this->peek().span()});
     }
     return ast;
   }

test/test-parse-expression-jsx.cpp

@@ -320,6 +320,13 @@ TEST_F(test_parse_expression, tag_with_member_expression) {
     ASSERT_EQ(summarize(ast), "jsxmemberelement((a-b, c-d))");
   }
 }
+
+TEST_F(test_parse_expression, jsx_with_binary_operator) {
+  {
+    expression* ast = this->parse_expression(u8"x && <div />"_sv, jsx_options);
+    ASSERT_EQ(summarize(ast), "binary(var x, jsxelement(div))");
+  }
+}
 }
 }