Highlight variable name in a for-loop (#326)

Signed-off-by: Konstantin Kharlamov <[email protected]>

Author: Hi-Angel

rust-mode-tests.el

@@ -3118,6 +3118,18 @@ impl Two<'a> {
      "b" font-lock-variable-name-face
      "u32" font-lock-type-face)))
 
+(ert-deftest variable-in-for-loop ()
+  (rust-test-font-lock
+   "for var in iter"
+   '("for" font-lock-keyword-face
+     "var" font-lock-variable-name-face
+     "in" font-lock-keyword-face))
+  (rust-test-font-lock
+   "for Foo{var} in iter"
+   '("for" font-lock-keyword-face
+     "Foo" font-lock-type-face
+     "in" font-lock-keyword-face)))
+
 (when (executable-find rust-cargo-bin)
   (ert-deftest rust-test-project-located ()
     (lexical-let* ((test-dir (expand-file-name "test-project" default-directory))

rust-mode.el

@@ -700,7 +700,7 @@ Returns nil if the point is not within a Rust string."
      (,rust-re-type-or-constructor 1 font-lock-type-face)
 
      ;; Type-inferred binding
-     (,(concat "\\_<\\(?:let\\s-+ref\\|let\\|ref\\)\\s-+\\(?:mut\\s-+\\)?" (rust-re-grab rust-re-ident) "\\_>") 1 font-lock-variable-name-face)
+     (,(concat "\\_<\\(?:let\\s-+ref\\|let\\|ref\\|for\\)\\s-+\\(?:mut\\s-+\\)?" (rust-re-grab rust-re-ident) "\\_>") 1 font-lock-variable-name-face)
 
      ;; Type names like `Foo::`, highlight excluding the ::
      (,(rust-path-font-lock-matcher rust-re-uc-ident) 1 font-lock-type-face)