Merge pull request #19933 from Veykril/push-uyxorpyvnzsl

Better parser recovery for macro calls in type bound position

Author: Veykril

crates/parser/src/grammar/generic_params.rs

@@ -201,6 +201,17 @@ fn type_bound(p: &mut Parser<'_>) -> bool {
             }
             if paths::is_use_path_start(p) {
                 types::path_type_bounds(p, false);
+                // test_err type_bounds_macro_call_recovery
+                // fn foo<T: T![], T: T!, T: T!{}>() -> Box<T! + T!{}> {}
+                if p.at(T![!]) {
+                    let m = p.start();
+                    p.bump(T![!]);
+                    p.error("unexpected `!` in type path, macro calls are not allowed here");
+                    if p.at_ts(TokenSet::new(&[T!['{'], T!['['], T!['(']])) {
+                        items::token_tree(p);
+                    }
+                    m.complete(p, ERROR);
+                }
             } else {
                 m.abandon(p);
                 return false;

crates/parser/src/grammar/paths.rs

@@ -98,7 +98,7 @@ fn path_segment(p: &mut Parser<'_>, mode: Mode, first: bool) -> Option<Completed
         types::type_(p);
         if p.eat(T![as]) {
             if is_use_path_start(p) {
-                types::path_type(p);
+                types::path_type_bounds(p, true);
             } else {
                 p.error("expected a trait");
             }

crates/parser/src/grammar/types.rs

@@ -330,15 +330,6 @@ fn bare_dyn_trait_type(p: &mut Parser<'_>) {
     m.complete(p, DYN_TRAIT_TYPE);
 }
 
-// test path_type
-// type A = Foo;
-// type B = ::Foo;
-// type C = self::Foo;
-// type D = super::Foo;
-pub(super) fn path_type(p: &mut Parser<'_>) {
-    path_type_bounds(p, true);
-}
-
 // test macro_call_type
 // type A = foo!();
 // type B = crate::foo!();
@@ -365,6 +356,11 @@ fn path_or_macro_type(p: &mut Parser<'_>, allow_bounds: bool) {
     }
 }
 
+// test path_type
+// type A = Foo;
+// type B = ::Foo;
+// type C = self::Foo;
+// type D = super::Foo;
 pub(super) fn path_type_bounds(p: &mut Parser<'_>, allow_bounds: bool) {
     assert!(paths::is_path_start(p));
     let m = p.start();

crates/parser/test_data/generated/runner.rs

@@ -876,6 +876,10 @@ mod err {
         run_and_expect_errors("test_data/parser/inline/err/tuple_pat_leading_comma.rs");
     }
     #[test]
+    fn type_bounds_macro_call_recovery() {
+        run_and_expect_errors("test_data/parser/inline/err/type_bounds_macro_call_recovery.rs");
+    }
+    #[test]
     fn type_in_array_recover() {
         run_and_expect_errors("test_data/parser/inline/err/type_in_array_recover.rs");
     }

crates/parser/test_data/parser/inline/err/type_bounds_macro_call_recovery.rast

@@ -0,0 +1,112 @@
+SOURCE_FILE
+  FN
+    FN_KW "fn"
+    WHITESPACE " "
+    NAME
+      IDENT "foo"
+    GENERIC_PARAM_LIST
+      L_ANGLE "<"
+      TYPE_PARAM
+        NAME
+          IDENT "T"
+        COLON ":"
+        WHITESPACE " "
+        TYPE_BOUND_LIST
+          TYPE_BOUND
+            PATH_TYPE
+              PATH
+                PATH_SEGMENT
+                  NAME_REF
+                    IDENT "T"
+            ERROR
+              BANG "!"
+              TOKEN_TREE
+                L_BRACK "["
+                R_BRACK "]"
+      COMMA ","
+      WHITESPACE " "
+      TYPE_PARAM
+        NAME
+          IDENT "T"
+        COLON ":"
+        WHITESPACE " "
+        TYPE_BOUND_LIST
+          TYPE_BOUND
+            PATH_TYPE
+              PATH
+                PATH_SEGMENT
+                  NAME_REF
+                    IDENT "T"
+            ERROR
+              BANG "!"
+      COMMA ","
+      WHITESPACE " "
+      TYPE_PARAM
+        NAME
+          IDENT "T"
+        COLON ":"
+        WHITESPACE " "
+        TYPE_BOUND_LIST
+          TYPE_BOUND
+            PATH_TYPE
+              PATH
+                PATH_SEGMENT
+                  NAME_REF
+                    IDENT "T"
+            ERROR
+              BANG "!"
+              TOKEN_TREE
+                L_CURLY "{"
+                R_CURLY "}"
+      R_ANGLE ">"
+    PARAM_LIST
+      L_PAREN "("
+      R_PAREN ")"
+    WHITESPACE " "
+    RET_TYPE
+      THIN_ARROW "->"
+      WHITESPACE " "
+      PATH_TYPE
+        PATH
+          PATH_SEGMENT
+            NAME_REF
+              IDENT "Box"
+            GENERIC_ARG_LIST
+              L_ANGLE "<"
+              TYPE_ARG
+                DYN_TRAIT_TYPE
+                  TYPE_BOUND_LIST
+                    TYPE_BOUND
+                      MACRO_TYPE
+                        MACRO_CALL
+                          PATH
+                            PATH_SEGMENT
+                              NAME_REF
+                                IDENT "T"
+                          BANG "!"
+                    WHITESPACE " "
+                    PLUS "+"
+                    WHITESPACE " "
+                    TYPE_BOUND
+                      PATH_TYPE
+                        PATH
+                          PATH_SEGMENT
+                            NAME_REF
+                              IDENT "T"
+                      ERROR
+                        BANG "!"
+                        TOKEN_TREE
+                          L_CURLY "{"
+                          R_CURLY "}"
+              R_ANGLE ">"
+    WHITESPACE " "
+    BLOCK_EXPR
+      STMT_LIST
+        L_CURLY "{"
+        R_CURLY "}"
+  WHITESPACE "\n"
+error 12: unexpected `!` in type path, macro calls are not allowed here
+error 21: unexpected `!` in type path, macro calls are not allowed here
+error 28: unexpected `!` in type path, macro calls are not allowed here
+error 43: expected `{`, `[`, `(`
+error 48: unexpected `!` in type path, macro calls are not allowed here

crates/parser/test_data/parser/inline/err/type_bounds_macro_call_recovery.rs

@@ -0,0 +1 @@
+fn foo<T: T![], T: T!, T: T!{}>() -> Box<T! + T!{}> {}