From 4e219e6335a04cae15a784063f8cbe021076c933 Mon Sep 17 00:00:00 2001
From: Fabian Wolff <fabian.wolff@alumni.ethz.ch>
Date: Fri, 4 Jun 2021 19:48:24 +0200
Subject: [PATCH 1/2] Remove incorrect assertion in type parsing code
---
compiler/rustc_parse/src/parser/ty.rs | 1 -
src/test/ui/parser/issue-84148-1.rs | 4 ++++
src/test/ui/parser/issue-84148-1.stderr | 23 ++++++++++++++++++
src/test/ui/parser/issue-84148-2.rs | 4 ++++
src/test/ui/parser/issue-84148-2.stderr | 31 +++++++++++++++++++++++++
5 files changed, 62 insertions(+), 1 deletion(-)
create mode 100644 src/test/ui/parser/issue-84148-1.rs
create mode 100644 src/test/ui/parser/issue-84148-1.stderr
create mode 100644 src/test/ui/parser/issue-84148-2.rs
create mode 100644 src/test/ui/parser/issue-84148-2.stderr
diff --git a/compiler/rustc_parse/src/parser/ty.rs b/compiler/rustc_parse/src/parser/ty.rs
index 89cf2d7876e1d..de5a5632600e4 100644
--- a/compiler/rustc_parse/src/parser/ty.rs
+++ b/compiler/rustc_parse/src/parser/ty.rs
@@ -334,7 +334,6 @@ impl<'a> Parser<'a> {
mut bounds: GenericBounds,
plus: bool,
) -> PResult<'a, TyKind> {
- assert_ne!(self.token, token::Question);
if plus {
self.eat_plus(); // `+`, or `+=` gets split and `+` is discarded
bounds.append(&mut self.parse_generic_bounds(Some(self.prev_token.span))?);
diff --git a/src/test/ui/parser/issue-84148-1.rs b/src/test/ui/parser/issue-84148-1.rs
new file mode 100644
index 0000000000000..25f7ba4d1f88e
--- /dev/null
+++ b/src/test/ui/parser/issue-84148-1.rs
@@ -0,0 +1,4 @@
+fn f(t:for<>t?)
+//~^ ERROR: expected parameter name
+//~| ERROR: expected one of
+//~| ERROR: expected one of
diff --git a/src/test/ui/parser/issue-84148-1.stderr b/src/test/ui/parser/issue-84148-1.stderr
new file mode 100644
index 0000000000000..98506568d82c2
--- /dev/null
+++ b/src/test/ui/parser/issue-84148-1.stderr
@@ -0,0 +1,23 @@
+error: expected parameter name, found `?`
+ --> $DIR/issue-84148-1.rs:1:14
+ |
+LL | fn f(t:for<>t?)
+ | ^ expected parameter name
+
+error: expected one of `(`, `)`, `+`, `,`, `::`, or `<`, found `?`
+ --> $DIR/issue-84148-1.rs:1:14
+ |
+LL | fn f(t:for<>t?)
+ | ^
+ | |
+ | expected one of `(`, `)`, `+`, `,`, `::`, or `<`
+ | help: missing `,`
+
+error: expected one of `->`, `;`, `where`, or `{`, found `<eof>`
+ --> $DIR/issue-84148-1.rs:1:15
+ |
+LL | fn f(t:for<>t?)
+ | ^ expected one of `->`, `;`, `where`, or `{`
+
+error: aborting due to 3 previous errors
+
diff --git a/src/test/ui/parser/issue-84148-2.rs b/src/test/ui/parser/issue-84148-2.rs
new file mode 100644
index 0000000000000..257a3fd67207e
--- /dev/null
+++ b/src/test/ui/parser/issue-84148-2.rs
@@ -0,0 +1,4 @@
+// error-pattern: this file contains an unclosed delimiter
+// error-pattern: expected parameter name
+// error-pattern: expected one of
+fn f(t:for<>t?
diff --git a/src/test/ui/parser/issue-84148-2.stderr b/src/test/ui/parser/issue-84148-2.stderr
new file mode 100644
index 0000000000000..6f314da436070
--- /dev/null
+++ b/src/test/ui/parser/issue-84148-2.stderr
@@ -0,0 +1,31 @@
+error: this file contains an unclosed delimiter
+ --> $DIR/issue-84148-2.rs:4:16
+ |
+LL | fn f(t:for<>t?
+ | - ^
+ | |
+ | unclosed delimiter
+
+error: expected parameter name, found `?`
+ --> $DIR/issue-84148-2.rs:4:14
+ |
+LL | fn f(t:for<>t?
+ | ^ expected parameter name
+
+error: expected one of `(`, `)`, `+`, `,`, `::`, or `<`, found `?`
+ --> $DIR/issue-84148-2.rs:4:14
+ |
+LL | fn f(t:for<>t?
+ | ^
+ | |
+ | expected one of `(`, `)`, `+`, `,`, `::`, or `<`
+ | help: missing `,`
+
+error: expected one of `->`, `;`, `where`, or `{`, found `<eof>`
+ --> $DIR/issue-84148-2.rs:4:16
+ |
+LL | fn f(t:for<>t?
+ | ^ expected one of `->`, `;`, `where`, or `{`
+
+error: aborting due to 4 previous errors
+
From 6a6a605a61dfacfa974582484236155ce041a21d Mon Sep 17 00:00:00 2001
From: Fabian Wolff <fabian.wolff@alumni.ethz.ch>
Date: Fri, 4 Jun 2021 22:46:57 +0200
Subject: [PATCH 2/2] Fix handling of unmatched angle brackets in parser
---
compiler/rustc_parse/src/parser/path.rs | 84 +++++++++++---------
src/test/ui/parser/issue-84104.rs | 3 +
src/test/ui/parser/issue-84104.stderr | 16 ++++
src/test/ui/parser/unmatched-langle-1.rs | 9 +++
src/test/ui/parser/unmatched-langle-1.stderr | 22 +++++
src/test/ui/parser/unmatched-langle-2.rs | 15 ++++
src/test/ui/parser/unmatched-langle-2.stderr | 8 ++
7 files changed, 120 insertions(+), 37 deletions(-)
create mode 100644 src/test/ui/parser/issue-84104.rs
create mode 100644 src/test/ui/parser/issue-84104.stderr
create mode 100644 src/test/ui/parser/unmatched-langle-1.rs
create mode 100644 src/test/ui/parser/unmatched-langle-1.stderr
create mode 100644 src/test/ui/parser/unmatched-langle-2.rs
create mode 100644 src/test/ui/parser/unmatched-langle-2.stderr
diff --git a/compiler/rustc_parse/src/parser/path.rs b/compiler/rustc_parse/src/parser/path.rs
index 9cc600d9ede02..953c6915068af 100644
--- a/compiler/rustc_parse/src/parser/path.rs
+++ b/compiler/rustc_parse/src/parser/path.rs
@@ -352,49 +352,59 @@ impl<'a> Parser<'a> {
debug!("parse_generic_args_with_leading_angle_bracket_recovery: (snapshotting)");
match self.parse_angle_args() {
Ok(args) => Ok(args),
- Err(ref mut e) if is_first_invocation && self.unmatched_angle_bracket_count > 0 => {
- // Cancel error from being unable to find `>`. We know the error
- // must have been this due to a non-zero unmatched angle bracket
- // count.
- e.cancel();
-
+ Err(mut e) if is_first_invocation && self.unmatched_angle_bracket_count > 0 => {
// Swap `self` with our backup of the parser state before attempting to parse
// generic arguments.
let snapshot = mem::replace(self, snapshot.unwrap());
- debug!(
- "parse_generic_args_with_leading_angle_bracket_recovery: (snapshot failure) \
- snapshot.count={:?}",
- snapshot.unmatched_angle_bracket_count,
- );
-
// Eat the unmatched angle brackets.
- for _ in 0..snapshot.unmatched_angle_bracket_count {
- self.eat_lt();
- }
-
- // Make a span over ${unmatched angle bracket count} characters.
- let span = lo.with_hi(lo.lo() + BytePos(snapshot.unmatched_angle_bracket_count));
- self.struct_span_err(
- span,
- &format!(
- "unmatched angle bracket{}",
- pluralize!(snapshot.unmatched_angle_bracket_count)
- ),
- )
- .span_suggestion(
- span,
- &format!(
- "remove extra angle bracket{}",
- pluralize!(snapshot.unmatched_angle_bracket_count)
- ),
- String::new(),
- Applicability::MachineApplicable,
- )
- .emit();
+ let all_angle_brackets = (0..snapshot.unmatched_angle_bracket_count)
+ .fold(true, |a, _| a && self.eat_lt());
+
+ if !all_angle_brackets {
+ // If there are other tokens in between the extraneous `<`s, we cannot simply
+ // suggest to remove them. This check also prevents us from accidentally ending
+ // up in the middle of a multibyte character (issue #84104).
+ let _ = mem::replace(self, snapshot);
+ Err(e)
+ } else {
+ // Cancel error from being unable to find `>`. We know the error
+ // must have been this due to a non-zero unmatched angle bracket
+ // count.
+ e.cancel();
+
+ debug!(
+ "parse_generic_args_with_leading_angle_bracket_recovery: (snapshot failure) \
+ snapshot.count={:?}",
+ snapshot.unmatched_angle_bracket_count,
+ );
+
+ // Make a span over ${unmatched angle bracket count} characters.
+ // This is safe because `all_angle_brackets` ensures that there are only `<`s,
+ // i.e. no multibyte characters, in this range.
+ let span =
+ lo.with_hi(lo.lo() + BytePos(snapshot.unmatched_angle_bracket_count));
+ self.struct_span_err(
+ span,
+ &format!(
+ "unmatched angle bracket{}",
+ pluralize!(snapshot.unmatched_angle_bracket_count)
+ ),
+ )
+ .span_suggestion(
+ span,
+ &format!(
+ "remove extra angle bracket{}",
+ pluralize!(snapshot.unmatched_angle_bracket_count)
+ ),
+ String::new(),
+ Applicability::MachineApplicable,
+ )
+ .emit();
- // Try again without unmatched angle bracket characters.
- self.parse_angle_args()
+ // Try again without unmatched angle bracket characters.
+ self.parse_angle_args()
+ }
}
Err(e) => Err(e),
}
diff --git a/src/test/ui/parser/issue-84104.rs b/src/test/ui/parser/issue-84104.rs
new file mode 100644
index 0000000000000..998949b94a4ba
--- /dev/null
+++ b/src/test/ui/parser/issue-84104.rs
@@ -0,0 +1,3 @@
+// error-pattern: this file contains an unclosed delimiter
+// error-pattern: expected one of
+#[i=i::<ښܖ<
diff --git a/src/test/ui/parser/issue-84104.stderr b/src/test/ui/parser/issue-84104.stderr
new file mode 100644
index 0000000000000..aff31f2c97149
--- /dev/null
+++ b/src/test/ui/parser/issue-84104.stderr
@@ -0,0 +1,16 @@
+error: this file contains an unclosed delimiter
+ --> $DIR/issue-84104.rs:3:13
+ |
+LL | #[i=i::<ښܖ<
+ | - ^
+ | |
+ | unclosed delimiter
+
+error: expected one of `>`, a const expression, lifetime, or type, found `]`
+ --> $DIR/issue-84104.rs:3:13
+ |
+LL | #[i=i::<ښܖ<
+ | ^ expected one of `>`, a const expression, lifetime, or type
+
+error: aborting due to 2 previous errors
+
diff --git a/src/test/ui/parser/unmatched-langle-1.rs b/src/test/ui/parser/unmatched-langle-1.rs
new file mode 100644
index 0000000000000..fdf2ae398014b
--- /dev/null
+++ b/src/test/ui/parser/unmatched-langle-1.rs
@@ -0,0 +1,9 @@
+// Check that a suggestion is issued if there are too many `<`s in a
+// generic argument list, and that the parser recovers properly.
+
+fn main() {
+ foo::<<<<Ty<i32>>();
+ //~^ ERROR: unmatched angle brackets
+ //~| ERROR: cannot find function `foo` in this scope [E0425]
+ //~| ERROR: cannot find type `Ty` in this scope [E0412]
+}
diff --git a/src/test/ui/parser/unmatched-langle-1.stderr b/src/test/ui/parser/unmatched-langle-1.stderr
new file mode 100644
index 0000000000000..c8072b4c59ad2
--- /dev/null
+++ b/src/test/ui/parser/unmatched-langle-1.stderr
@@ -0,0 +1,22 @@
+error: unmatched angle brackets
+ --> $DIR/unmatched-langle-1.rs:5:10
+ |
+LL | foo::<<<<Ty<i32>>();
+ | ^^^ help: remove extra angle brackets
+
+error[E0425]: cannot find function `foo` in this scope
+ --> $DIR/unmatched-langle-1.rs:5:5
+ |
+LL | foo::<<<<Ty<i32>>();
+ | ^^^ not found in this scope
+
+error[E0412]: cannot find type `Ty` in this scope
+ --> $DIR/unmatched-langle-1.rs:5:14
+ |
+LL | foo::<<<<Ty<i32>>();
+ | ^^ not found in this scope
+
+error: aborting due to 3 previous errors
+
+Some errors have detailed explanations: E0412, E0425.
+For more information about an error, try `rustc --explain E0412`.
diff --git a/src/test/ui/parser/unmatched-langle-2.rs b/src/test/ui/parser/unmatched-langle-2.rs
new file mode 100644
index 0000000000000..8de0d7d89e4e7
--- /dev/null
+++ b/src/test/ui/parser/unmatched-langle-2.rs
@@ -0,0 +1,15 @@
+// When there are too many opening `<`s, the compiler would previously
+// suggest nonsense if the `<`s were interspersed with other tokens:
+//
+// error: unmatched angle brackets
+// --> unmatched-langle.rs:2:10
+// |
+// 2 | foo::<Ty<<<i32>();
+// | ^^^ help: remove extra angle brackets
+//
+// This test makes sure that this is no longer happening.
+
+fn main() {
+ foo::<Ty<<<i32>();
+ //~^ ERROR: expected `::`, found `(`
+}
diff --git a/src/test/ui/parser/unmatched-langle-2.stderr b/src/test/ui/parser/unmatched-langle-2.stderr
new file mode 100644
index 0000000000000..773bb33d8d3f3
--- /dev/null
+++ b/src/test/ui/parser/unmatched-langle-2.stderr
@@ -0,0 +1,8 @@
+error: expected `::`, found `(`
+ --> $DIR/unmatched-langle-2.rs:13:20
+ |
+LL | foo::<Ty<<<i32>();
+ | ^ expected `::`
+
+error: aborting due to previous error
+