From 45c1e381473b39e7fece2663638d09288370a821 Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Fri, 13 Dec 2019 00:59:33 +0100
Subject: [PATCH] parser: recover on `&'lifetime mut $pat`.
---
src/librustc_parse/parser/pat.rs | 22 +++++++++++++-----
.../ui/parser/lifetime-in-pattern-recover.rs | 6 +++++
.../parser/lifetime-in-pattern-recover.stderr | 23 +++++++++++++++++++
src/test/ui/parser/lifetime-in-pattern.rs | 1 +
src/test/ui/parser/lifetime-in-pattern.stderr | 10 ++++++--
.../ui/self/self-vs-path-ambiguity.stderr | 2 +-
6 files changed, 55 insertions(+), 9 deletions(-)
create mode 100644 src/test/ui/parser/lifetime-in-pattern-recover.rs
create mode 100644 src/test/ui/parser/lifetime-in-pattern-recover.stderr
diff --git a/src/librustc_parse/parser/pat.rs b/src/librustc_parse/parser/pat.rs
index 42ece96adb99a..117b92dc9a574 100644
--- a/src/librustc_parse/parser/pat.rs
+++ b/src/librustc_parse/parser/pat.rs
@@ -459,16 +459,26 @@ impl<'a> Parser<'a> {
/// Parse `&pat` / `&mut pat`.
fn parse_pat_deref(&mut self, expected: Expected) -> PResult<'a, PatKind> {
self.expect_and()?;
+ self.recover_lifetime_in_deref_pat();
let mutbl = self.parse_mutability();
+ let subpat = self.parse_pat_with_range_pat(false, expected)?;
+ Ok(PatKind::Ref(subpat, mutbl))
+ }
+ fn recover_lifetime_in_deref_pat(&mut self) {
if let token::Lifetime(name) = self.token.kind {
- let mut err = self.fatal(&format!("unexpected lifetime `{}` in pattern", name));
- err.span_label(self.token.span, "unexpected lifetime");
- return Err(err);
- }
+ self.bump(); // `'a`
- let subpat = self.parse_pat_with_range_pat(false, expected)?;
- Ok(PatKind::Ref(subpat, mutbl))
+ let span = self.prev_span;
+ self.struct_span_err(span, &format!("unexpected lifetime `{}` in pattern", name))
+ .span_suggestion(
+ span,
+ "remove the lifetime",
+ String::new(),
+ Applicability::MachineApplicable,
+ )
+ .emit();
+ }
}
/// Parse a tuple or parenthesis pattern.
diff --git a/src/test/ui/parser/lifetime-in-pattern-recover.rs b/src/test/ui/parser/lifetime-in-pattern-recover.rs
new file mode 100644
index 0000000000000..7fb14b8007671
--- /dev/null
+++ b/src/test/ui/parser/lifetime-in-pattern-recover.rs
@@ -0,0 +1,6 @@
+fn main() {
+ let &'a x = &0; //~ ERROR unexpected lifetime `'a` in pattern
+ let &'a mut y = &mut 0; //~ ERROR unexpected lifetime `'a` in pattern
+
+ let _recovery_witness: () = 0; //~ ERROR mismatched types
+}
diff --git a/src/test/ui/parser/lifetime-in-pattern-recover.stderr b/src/test/ui/parser/lifetime-in-pattern-recover.stderr
new file mode 100644
index 0000000000000..4bf7f57bfb59f
--- /dev/null
+++ b/src/test/ui/parser/lifetime-in-pattern-recover.stderr
@@ -0,0 +1,23 @@
+error: unexpected lifetime `'a` in pattern
+ --> $DIR/lifetime-in-pattern-recover.rs:2:10
+ |
+LL | let &'a x = &0;
+ | ^^ help: remove the lifetime
+
+error: unexpected lifetime `'a` in pattern
+ --> $DIR/lifetime-in-pattern-recover.rs:3:10
+ |
+LL | let &'a mut y = &mut 0;
+ | ^^ help: remove the lifetime
+
+error[E0308]: mismatched types
+ --> $DIR/lifetime-in-pattern-recover.rs:5:33
+ |
+LL | let _recovery_witness: () = 0;
+ | -- ^ expected `()`, found integer
+ | |
+ | expected due to this
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/parser/lifetime-in-pattern.rs b/src/test/ui/parser/lifetime-in-pattern.rs
index afee685cd056f..d3c638d0cd74b 100644
--- a/src/test/ui/parser/lifetime-in-pattern.rs
+++ b/src/test/ui/parser/lifetime-in-pattern.rs
@@ -1,5 +1,6 @@
fn test(&'a str) {
//~^ ERROR unexpected lifetime `'a` in pattern
+ //~| ERROR expected one of `:`, `@`, or `|`, found `)`
}
fn main() {
diff --git a/src/test/ui/parser/lifetime-in-pattern.stderr b/src/test/ui/parser/lifetime-in-pattern.stderr
index e525c7b6d680f..71fd3cdf72370 100644
--- a/src/test/ui/parser/lifetime-in-pattern.stderr
+++ b/src/test/ui/parser/lifetime-in-pattern.stderr
@@ -2,7 +2,13 @@ error: unexpected lifetime `'a` in pattern
--> $DIR/lifetime-in-pattern.rs:1:10
|
LL | fn test(&'a str) {
- | ^^ unexpected lifetime
+ | ^^ help: remove the lifetime
-error: aborting due to previous error
+error: expected one of `:`, `@`, or `|`, found `)`
+ --> $DIR/lifetime-in-pattern.rs:1:16
+ |
+LL | fn test(&'a str) {
+ | ^ expected one of `:`, `@`, or `|`
+
+error: aborting due to 2 previous errors
diff --git a/src/test/ui/self/self-vs-path-ambiguity.stderr b/src/test/ui/self/self-vs-path-ambiguity.stderr
index 5ce6a81bfcfd7..2beef50cdb5c6 100644
--- a/src/test/ui/self/self-vs-path-ambiguity.stderr
+++ b/src/test/ui/self/self-vs-path-ambiguity.stderr
@@ -2,7 +2,7 @@ error: unexpected lifetime `'a` in pattern
--> $DIR/self-vs-path-ambiguity.rs:9:11
|
LL | fn i(&'a self::S: &S) {}
- | ^^ unexpected lifetime
+ | ^^ help: remove the lifetime
error: aborting due to previous error