Merge branch 'master' into m-lambda-to-fn

Author: jessetrinity

.gitmodules

@@ -28769,7 +28769,14 @@ namespace ts {
                     }
                 case SyntaxKind.CommaToken:
                     if (!compilerOptions.allowUnreachableCode && isSideEffectFree(left) && !isEvalNode(right)) {
-                        error(left, Diagnostics.Left_side_of_comma_operator_is_unused_and_has_no_side_effects);
+                        const sf = getSourceFileOfNode(left);
+                        const sourceText = sf.text;
+                        const start = skipTrivia(sourceText, left.pos);
+                        const isInDiag2657 = sf.parseDiagnostics.some(diag => {
+                            if (diag.code !== Diagnostics.JSX_expressions_must_have_one_parent_element.code) return false;
+                            return textSpanContainsPosition(diag, start);
+                        });
+                        if (!isInDiag2657) error(left, Diagnostics.Left_side_of_comma_operator_is_unused_and_has_no_side_effects);
                     }
                     return rightType;