From 44e47fe4083adbd35889da7a6489ec3252a4f04b Mon Sep 17 00:00:00 2001
From: shilangyu <xmarcinmarcin@gmail.com>
Date: Sat, 25 Feb 2023 16:16:49 +0100
Subject: [PATCH] Add check for extra path segments after an angled one

---
 .../macro_expansion_tests/mbe/regression.rs   |  1 +
 crates/parser/src/grammar/paths.rs            |  6 +++
 .../err/0016_angled_path_without_qual.rast    | 49 +++++++++++++++++++
 .../err/0016_angled_path_without_qual.rs      |  2 +
 4 files changed, 58 insertions(+)
 create mode 100644 crates/parser/test_data/parser/inline/err/0016_angled_path_without_qual.rast
 create mode 100644 crates/parser/test_data/parser/inline/err/0016_angled_path_without_qual.rs

diff --git a/crates/hir-def/src/macro_expansion_tests/mbe/regression.rs b/crates/hir-def/src/macro_expansion_tests/mbe/regression.rs
index 8358a46f0a9..b663a291789 100644
--- a/crates/hir-def/src/macro_expansion_tests/mbe/regression.rs
+++ b/crates/hir-def/src/macro_expansion_tests/mbe/regression.rs
@@ -827,6 +827,7 @@ pub fn new() {
 /* parse error: expected type */
 /* parse error: expected R_PAREN */
 /* parse error: expected R_ANGLE */
+/* parse error: expected `::` */
 /* parse error: expected COMMA */
 /* parse error: expected R_ANGLE */
 /* parse error: expected SEMICOLON */
diff --git a/crates/parser/src/grammar/paths.rs b/crates/parser/src/grammar/paths.rs
index 1064ae9970c..26490aa97e0 100644
--- a/crates/parser/src/grammar/paths.rs
+++ b/crates/parser/src/grammar/paths.rs
@@ -77,6 +77,9 @@ fn path_segment(p: &mut Parser<'_>, mode: Mode, first: bool) {
     // type X = <A as B>::Output;
     // fn foo() { <usize as Default>::default(); }
     if first && p.eat(T![<]) {
+        // test_err angled_path_without_qual
+        // type X = <()>;
+        // type Y = <A as B>;
         types::type_(p);
         if p.eat(T![as]) {
             if is_use_path_start(p) {
@@ -86,6 +89,9 @@ fn path_segment(p: &mut Parser<'_>, mode: Mode, first: bool) {
             }
         }
         p.expect(T![>]);
+        if !p.at(T![::]) {
+            p.error("expected `::`");
+        }
     } else {
         let empty = if first {
             p.eat(T![::]);
diff --git a/crates/parser/test_data/parser/inline/err/0016_angled_path_without_qual.rast b/crates/parser/test_data/parser/inline/err/0016_angled_path_without_qual.rast
new file mode 100644
index 00000000000..0529e9750e7
--- /dev/null
+++ b/crates/parser/test_data/parser/inline/err/0016_angled_path_without_qual.rast
@@ -0,0 +1,49 @@
+SOURCE_FILE
+  TYPE_ALIAS
+    TYPE_KW "type"
+    WHITESPACE " "
+    NAME
+      IDENT "X"
+    WHITESPACE " "
+    EQ "="
+    WHITESPACE " "
+    PATH_TYPE
+      PATH
+        PATH_SEGMENT
+          L_ANGLE "<"
+          TUPLE_TYPE
+            L_PAREN "("
+            R_PAREN ")"
+          R_ANGLE ">"
+    SEMICOLON ";"
+  WHITESPACE "\n"
+  TYPE_ALIAS
+    TYPE_KW "type"
+    WHITESPACE " "
+    NAME
+      IDENT "Y"
+    WHITESPACE " "
+    EQ "="
+    WHITESPACE " "
+    PATH_TYPE
+      PATH
+        PATH_SEGMENT
+          L_ANGLE "<"
+          PATH_TYPE
+            PATH
+              PATH_SEGMENT
+                NAME_REF
+                  IDENT "A"
+          WHITESPACE " "
+          AS_KW "as"
+          WHITESPACE " "
+          PATH_TYPE
+            PATH
+              PATH_SEGMENT
+                NAME_REF
+                  IDENT "B"
+          R_ANGLE ">"
+    SEMICOLON ";"
+  WHITESPACE "\n"
+error 13: expected `::`
+error 32: expected `::`
diff --git a/crates/parser/test_data/parser/inline/err/0016_angled_path_without_qual.rs b/crates/parser/test_data/parser/inline/err/0016_angled_path_without_qual.rs
new file mode 100644
index 00000000000..802d6cc14a4
--- /dev/null
+++ b/crates/parser/test_data/parser/inline/err/0016_angled_path_without_qual.rs
@@ -0,0 +1,2 @@
+type X = <()>;
+type Y = <A as B>;