diff --git a/.lintr b/.lintr
index 27c6bef4..36675671 100644
--- a/.lintr
+++ b/.lintr
@@ -4,4 +4,5 @@ linters: linters_with_defaults(
     object_length_linter = NULL,
     object_name_linter = NULL,
     commented_code_linter = NULL,
-    cyclocomp_linter = NULL)
+    cyclocomp_linter = NULL,
+    indentation_linter(indent = 4, hanging_indent_style = "never"))
diff --git a/R/diagnostics.R b/R/diagnostics.R
index 7c534333..5078a657 100644
--- a/R/diagnostics.R
+++ b/R/diagnostics.R
@@ -97,7 +97,12 @@ diagnose_file <- function(uri, content, is_rmarkdown = FALSE, globals = NULL, ca
         on.exit(do.call("detach", list(env_name, character.only = TRUE)))
     }
 
-    lints <- lintr::lint(path, cache = cache, text = content)
+    if (file.exists(path)) {
+        lints <- lintr::lint(path, cache = cache, text = content)
+    } else {
+        lints <- lintr::lint(text = content, cache = cache)
+    }
+
     diagnostics <- lapply(lints, diagnostic_from_lint, content = content)
     names(diagnostics) <- NULL
     diagnostics