From d786a40e73f2b2f7ab4f77e9fb880b5d06ca1cdb Mon Sep 17 00:00:00 2001
From: Chayim Refael Friedman <chayimfr@gmail.com>
Date: Wed, 31 Aug 2022 23:19:09 +0000
Subject: [PATCH] Parse TypePathFn with preceding `::`

e.g. `impl Fn::() -> ()`.
---
 crates/parser/src/grammar/paths.rs            |  5 +++
 .../ok/0202_typepathfn_with_coloncolon.rast   | 43 +++++++++++++++++++
 .../ok/0202_typepathfn_with_coloncolon.rs     |  1 +
 3 files changed, 49 insertions(+)
 create mode 100644 crates/parser/test_data/parser/inline/ok/0202_typepathfn_with_coloncolon.rast
 create mode 100644 crates/parser/test_data/parser/inline/ok/0202_typepathfn_with_coloncolon.rs

diff --git a/crates/parser/src/grammar/paths.rs b/crates/parser/src/grammar/paths.rs
index 8de5d33a19..5dc9c6c82a 100644
--- a/crates/parser/src/grammar/paths.rs
+++ b/crates/parser/src/grammar/paths.rs
@@ -118,6 +118,11 @@ fn opt_path_type_args(p: &mut Parser<'_>, mode: Mode) {
     match mode {
         Mode::Use => {}
         Mode::Type => {
+            // test typepathfn_with_coloncolon
+            // type F = Start::(Middle) -> (Middle)::End;
+            if p.at(T![::]) && p.nth_at(2, T!['(']) {
+                p.bump(T![::]);
+            }
             // test path_fn_trait_args
             // type F = Box<Fn(i32) -> ()>;
             if p.at(T!['(']) {
diff --git a/crates/parser/test_data/parser/inline/ok/0202_typepathfn_with_coloncolon.rast b/crates/parser/test_data/parser/inline/ok/0202_typepathfn_with_coloncolon.rast
new file mode 100644
index 0000000000..b47a5a5c14
--- /dev/null
+++ b/crates/parser/test_data/parser/inline/ok/0202_typepathfn_with_coloncolon.rast
@@ -0,0 +1,43 @@
+SOURCE_FILE
+  TYPE_ALIAS
+    TYPE_KW "type"
+    WHITESPACE " "
+    NAME
+      IDENT "F"
+    WHITESPACE " "
+    EQ "="
+    WHITESPACE " "
+    PATH_TYPE
+      PATH
+        PATH
+          PATH_SEGMENT
+            NAME_REF
+              IDENT "Start"
+            COLON2 "::"
+            PARAM_LIST
+              L_PAREN "("
+              PARAM
+                PATH_TYPE
+                  PATH
+                    PATH_SEGMENT
+                      NAME_REF
+                        IDENT "Middle"
+              R_PAREN ")"
+            WHITESPACE " "
+            RET_TYPE
+              THIN_ARROW "->"
+              WHITESPACE " "
+              PAREN_TYPE
+                L_PAREN "("
+                PATH_TYPE
+                  PATH
+                    PATH_SEGMENT
+                      NAME_REF
+                        IDENT "Middle"
+                R_PAREN ")"
+        COLON2 "::"
+        PATH_SEGMENT
+          NAME_REF
+            IDENT "End"
+    SEMICOLON ";"
+  WHITESPACE "\n"
diff --git a/crates/parser/test_data/parser/inline/ok/0202_typepathfn_with_coloncolon.rs b/crates/parser/test_data/parser/inline/ok/0202_typepathfn_with_coloncolon.rs
new file mode 100644
index 0000000000..8efd93a7ff
--- /dev/null
+++ b/crates/parser/test_data/parser/inline/ok/0202_typepathfn_with_coloncolon.rs
@@ -0,0 +1 @@
+type F = Start::(Middle) -> (Middle)::End;