Declare lint.

1 files changed, 35 insertions, 0 deletions

diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs
index 073177b0f3d..b5f68817c35 100644
--- a/clippy_lints/src/methods/mod.rs
+++ b/clippy_lints/src/methods/mod.rs
@@ -1130,6 +1130,40 @@ declare_clippy_lint! {
     "Check for offset calculations on raw pointers to zero-sized types"
 }
 
+declare_clippy_lint! {
+    /// **What it does:** Checks for `FileType::is_file()`.
+    ///
+    /// **Why is this bad?** When people testing a file type with `FileType::is_file`
+    /// they are testing whether a path is something they can get bytes from. But
+    /// `is_file` doesn't cover special file types in unix-like systems. and not covering
+    /// symlink in windows. Using `!FileType::is_dir()` is a better way to that intention.
+    ///
+    /// **Example:**
+    ///
+    /// ```rust,ignore
+    /// let metadata = std::fs::metadata("foo.txt")?;
+    /// let filetype = metadata.file_type();
+    ///
+    /// if filetype.is_file() {
+    ///     // read file
+    /// }
+    /// ```
+    ///
+    /// should be writing as:
+    ///
+    /// ```rust,ignore
+    /// let metadata = std::fs::metadata("foo.txt")?;
+    /// let filetype = metadata.file_type();
+    ///
+    /// if !filetype.is_dir() {
+    ///     // read file
+    /// }
+    /// ```
+    pub FILETYPE_IS_FILE,
+    style,
+    "`FileType::is_file` is not recommended to test for readable file type."
+}
+
 declare_lint_pass!(Methods => [
     OPTION_UNWRAP_USED,
     RESULT_UNWRAP_USED,
@@ -1177,6 +1211,7 @@ declare_lint_pass!(Methods => [
     UNINIT_ASSUMED_INIT,
     MANUAL_SATURATING_ARITHMETIC,
     ZST_OFFSET,
+    FILETYPE_IS_FILE,
 ]);
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Methods {