From 09997e72272157a88c40cd2b1b1b7a14f808c0e0 Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Sat, 7 Mar 2020 11:00:40 +0100
Subject: [PATCH] error_block_no_opening_brace: handle closures better
---
src/librustc_parse/parser/stmt.rs | 16 +++++++---------
src/librustc_span/source_map.rs | 7 +++++++
.../ui/parser/attr-stmt-expr-attr-bad.stderr | 16 ++++++++--------
src/test/ui/parser/closure-return-syntax.stderr | 4 ++--
4 files changed, 24 insertions(+), 19 deletions(-)
diff --git a/src/librustc_parse/parser/stmt.rs b/src/librustc_parse/parser/stmt.rs
index 8afc86c704d..fb85f54b136 100644
--- a/src/librustc_parse/parser/stmt.rs
+++ b/src/librustc_parse/parser/stmt.rs
@@ -259,16 +259,14 @@ impl<'a> Parser<'a> {
//
// which is valid in other languages, but not Rust.
match self.parse_stmt_without_recovery() {
- Ok(Some(stmt)) => {
+ // If the next token is an open brace (e.g., `if a b {`), the place-
+ // inside-a-block suggestion would be more likely wrong than right.
+ Ok(Some(_))
if self.look_ahead(1, |t| t == &token::OpenDelim(token::Brace))
- || do_not_suggest_help
- {
- // If the next token is an open brace (e.g., `if a b {`), the place-
- // inside-a-block suggestion would be more likely wrong than right.
- e.span_label(sp, "expected `{`");
- return Err(e);
- }
- let stmt_span = if self.eat(&token::Semi) {
+ || do_not_suggest_help => {}
+ Ok(Some(stmt)) => {
+ let stmt_own_line = self.sess.source_map().is_line_before_span_empty(sp);
+ let stmt_span = if stmt_own_line && self.eat(&token::Semi) {
// Expand the span to include the semicolon.
stmt.span.with_hi(self.prev_token.span.hi())
} else {
diff --git a/src/librustc_span/source_map.rs b/src/librustc_span/source_map.rs
index cd2d2c4c3d7..5170f69e059 100644
--- a/src/librustc_span/source_map.rs
+++ b/src/librustc_span/source_map.rs
@@ -517,6 +517,13 @@ impl SourceMap {
Ok((lo, hi))
}
+ pub fn is_line_before_span_empty(&self, sp: Span) -> bool {
+ match self.span_to_prev_source(sp) {
+ Ok(s) => s.split('\n').last().map(|l| l.trim_start().is_empty()).unwrap_or(false),
+ Err(_) => false,
+ }
+ }
+
pub fn span_to_lines(&self, sp: Span) -> FileLinesResult {
debug!("span_to_lines(sp={:?})", sp);
let (lo, hi) = self.is_valid_span(sp)?;
diff --git a/src/test/ui/parser/attr-stmt-expr-attr-bad.stderr b/src/test/ui/parser/attr-stmt-expr-attr-bad.stderr
index 4dcba27cb68..af490150913 100644
--- a/src/test/ui/parser/attr-stmt-expr-attr-bad.stderr
+++ b/src/test/ui/parser/attr-stmt-expr-attr-bad.stderr
@@ -140,7 +140,7 @@ error: expected `{`, found `#`
--> $DIR/attr-stmt-expr-attr-bad.rs:41:37
|
LL | #[cfg(FALSE)] fn e() { let _ = if 0 #[attr] {}; }
- | -- ^ --- help: try placing this code inside a block: `{ {}; }`
+ | -- ^ -- help: try placing this code inside a block: `{ {} }`
| | |
| | expected `{`
| this `if` expression has a condition, but no block
@@ -163,7 +163,7 @@ error: expected `{`, found `#`
--> $DIR/attr-stmt-expr-attr-bad.rs:47:45
|
LL | #[cfg(FALSE)] fn e() { let _ = if 0 {} else #[attr] {}; }
- | ^ --- help: try placing this code inside a block: `{ {}; }`
+ | ^ -- help: try placing this code inside a block: `{ {} }`
| |
| expected `{`
@@ -179,7 +179,7 @@ error: expected `{`, found `#`
--> $DIR/attr-stmt-expr-attr-bad.rs:51:45
|
LL | #[cfg(FALSE)] fn e() { let _ = if 0 {} else #[attr] if 0 {}; }
- | ^ -------- help: try placing this code inside a block: `{ if 0 {}; }`
+ | ^ ------- help: try placing this code inside a block: `{ if 0 {} }`
| |
| expected `{`
@@ -187,7 +187,7 @@ error: expected `{`, found `#`
--> $DIR/attr-stmt-expr-attr-bad.rs:53:50
|
LL | #[cfg(FALSE)] fn e() { let _ = if 0 {} else if 0 #[attr] {}; }
- | -- ^ --- help: try placing this code inside a block: `{ {}; }`
+ | -- ^ -- help: try placing this code inside a block: `{ {} }`
| | |
| | expected `{`
| this `if` expression has a condition, but no block
@@ -204,7 +204,7 @@ error: expected `{`, found `#`
--> $DIR/attr-stmt-expr-attr-bad.rs:57:45
|
LL | #[cfg(FALSE)] fn e() { let _ = if let _ = 0 #[attr] {}; }
- | -- ^ --- help: try placing this code inside a block: `{ {}; }`
+ | -- ^ -- help: try placing this code inside a block: `{ {} }`
| | |
| | expected `{`
| this `if` expression has a condition, but no block
@@ -227,7 +227,7 @@ error: expected `{`, found `#`
--> $DIR/attr-stmt-expr-attr-bad.rs:63:53
|
LL | #[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} else #[attr] {}; }
- | ^ --- help: try placing this code inside a block: `{ {}; }`
+ | ^ -- help: try placing this code inside a block: `{ {} }`
| |
| expected `{`
@@ -243,7 +243,7 @@ error: expected `{`, found `#`
--> $DIR/attr-stmt-expr-attr-bad.rs:67:53
|
LL | #[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} else #[attr] if let _ = 0 {}; }
- | ^ ---------------- help: try placing this code inside a block: `{ if let _ = 0 {}; }`
+ | ^ --------------- help: try placing this code inside a block: `{ if let _ = 0 {} }`
| |
| expected `{`
@@ -251,7 +251,7 @@ error: expected `{`, found `#`
--> $DIR/attr-stmt-expr-attr-bad.rs:69:66
|
LL | #[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} else if let _ = 0 #[attr] {}; }
- | -- ^ --- help: try placing this code inside a block: `{ {}; }`
+ | -- ^ -- help: try placing this code inside a block: `{ {} }`
| | |
| | expected `{`
| this `if` expression has a condition, but no block
diff --git a/src/test/ui/parser/closure-return-syntax.stderr b/src/test/ui/parser/closure-return-syntax.stderr
index 7bf6202a72a..1ccdd977305 100644
--- a/src/test/ui/parser/closure-return-syntax.stderr
+++ b/src/test/ui/parser/closure-return-syntax.stderr
@@ -2,10 +2,10 @@ error: expected `{`, found `22`
--> $DIR/closure-return-syntax.rs:5:23
|
LL | let x = || -> i32 22;
- | ^^-
+ | ^^
| |
| expected `{`
- | help: try placing this code inside a block: `{ 22; }`
+ | help: try placing this code inside a block: `{ 22 }`
error: aborting due to previous error