From e6ce3ef80aad6df7e9971d126bb22619ab34927e Mon Sep 17 00:00:00 2001 From: wangxiangqing Date: Sun, 13 Oct 2019 12:59:23 +0800 Subject: [PATCH 1/3] Collect occurrences of for mismatched braces diagnostic Change-Id: I20ba0b62308370ee961141fa1aefc4b9c9f0cb3a --- src/libsyntax/parse/lexer/tokentrees.rs | 18 ++++++++++++++++-- src/libsyntax/parse/token.rs | 2 +- .../mismatched-delim-brace-empty-block.rs | 3 +++ .../mismatched-delim-brace-empty-block.stderr | 11 +++++++++++ 4 files changed, 31 insertions(+), 3 deletions(-) create mode 100644 src/test/ui/parser/mismatched-delim-brace-empty-block.rs create mode 100644 src/test/ui/parser/mismatched-delim-brace-empty-block.stderr diff --git a/src/libsyntax/parse/lexer/tokentrees.rs b/src/libsyntax/parse/lexer/tokentrees.rs index e5ba7e45309dd..fa494db2f9f36 100644 --- a/src/libsyntax/parse/lexer/tokentrees.rs +++ b/src/libsyntax/parse/lexer/tokentrees.rs @@ -1,3 +1,4 @@ +use rustc_data_structures::fx::FxHashMap; use syntax_pos::Span; use crate::print::pprust::token_to_string; @@ -16,6 +17,7 @@ impl<'a> StringReader<'a> { unmatched_braces: Vec::new(), matching_delim_spans: Vec::new(), last_unclosed_found_span: None, + last_delim_empty_block_spans: FxHashMap::default() }; let res = tt_reader.parse_all_token_trees(); (res, tt_reader.unmatched_braces) @@ -34,6 +36,7 @@ struct TokenTreesReader<'a> { /// Used only for error recovery when arriving to EOF with mismatched braces. matching_delim_spans: Vec<(token::DelimToken, Span, Span)>, last_unclosed_found_span: Option, + last_delim_empty_block_spans: FxHashMap } impl<'a> TokenTreesReader<'a> { @@ -121,13 +124,20 @@ impl<'a> TokenTreesReader<'a> { // Correct delimiter. token::CloseDelim(d) if d == delim => { let (open_brace, open_brace_span) = self.open_braces.pop().unwrap(); + let close_brace_span = self.token.span; + + if close_brace_span.lo() == open_brace_span.hi() { + let empty_block_span = open_brace_span.to(close_brace_span); + self.last_delim_empty_block_spans.insert(delim, empty_block_span); + } + if self.open_braces.len() == 0 { // Clear up these spans to avoid suggesting them as we've found // properly matched delimiters so far for an entire block. self.matching_delim_spans.clear(); } else { self.matching_delim_spans.push( - (open_brace, open_brace_span, self.token.span), + (open_brace, open_brace_span, close_brace_span), ); } // Parse the close delimiter. @@ -193,13 +203,17 @@ impl<'a> TokenTreesReader<'a> { tts.into() ).into()) }, - token::CloseDelim(_) => { + token::CloseDelim(delim) => { // An unexpected closing delimiter (i.e., there is no // matching opening delimiter). let token_str = token_to_string(&self.token); let msg = format!("unexpected close delimiter: `{}`", token_str); let mut err = self.string_reader.sess.span_diagnostic .struct_span_err(self.token.span, &msg); + + if let Some(span) = self.last_delim_empty_block_spans.remove(&delim) { + err.span_label(span, "this block is empty, you might have not meant to close it"); + } err.span_label(self.token.span, "unexpected close delimiter"); Err(err) }, diff --git a/src/libsyntax/parse/token.rs b/src/libsyntax/parse/token.rs index fd78a2bd53442..6038bcae5aefb 100644 --- a/src/libsyntax/parse/token.rs +++ b/src/libsyntax/parse/token.rs @@ -36,7 +36,7 @@ pub enum BinOpToken { } /// A delimiter token. -#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)] +#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)] pub enum DelimToken { /// A round parenthesis (i.e., `(` or `)`). Paren, diff --git a/src/test/ui/parser/mismatched-delim-brace-empty-block.rs b/src/test/ui/parser/mismatched-delim-brace-empty-block.rs new file mode 100644 index 0000000000000..bcc95c09e1e99 --- /dev/null +++ b/src/test/ui/parser/mismatched-delim-brace-empty-block.rs @@ -0,0 +1,3 @@ +fn main() {} + let _ = (); +} //~ ERROR unexpected close delimiter diff --git a/src/test/ui/parser/mismatched-delim-brace-empty-block.stderr b/src/test/ui/parser/mismatched-delim-brace-empty-block.stderr new file mode 100644 index 0000000000000..82fe8930c325f --- /dev/null +++ b/src/test/ui/parser/mismatched-delim-brace-empty-block.stderr @@ -0,0 +1,11 @@ +error: unexpected close delimiter: `}` + --> $DIR/mismatched-delim-brace-empty-block.rs:3:1 + | +LL | fn main() {} + | -- this block is empty, you might have not meant to close it +LL | let _ = (); +LL | } + | ^ unexpected close delimiter + +error: aborting due to previous error + From 888d0ba8df38681c08ac25f30ff4cbfad8168d90 Mon Sep 17 00:00:00 2001 From: wangxiangqing Date: Sun, 13 Oct 2019 12:59:23 +0800 Subject: [PATCH 2/3] Collect occurrences of for mismatched braces diagnostic Change-Id: I20ba0b62308370ee961141fa1aefc4b9c9f0cb3a --- src/libsyntax/parse/lexer/tokentrees.rs | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/src/libsyntax/parse/lexer/tokentrees.rs b/src/libsyntax/parse/lexer/tokentrees.rs index fa494db2f9f36..b088d160b923e 100644 --- a/src/libsyntax/parse/lexer/tokentrees.rs +++ b/src/libsyntax/parse/lexer/tokentrees.rs @@ -212,7 +212,10 @@ impl<'a> TokenTreesReader<'a> { .struct_span_err(self.token.span, &msg); if let Some(span) = self.last_delim_empty_block_spans.remove(&delim) { - err.span_label(span, "this block is empty, you might have not meant to close it"); + err.span_label( + span, + "this block is empty, you might have not meant to close it" + ); } err.span_label(self.token.span, "unexpected close delimiter"); Err(err) From fe819a074c748fd3d11fcc0be8164645a7cd58db Mon Sep 17 00:00:00 2001 From: wangxiangqing Date: Sun, 13 Oct 2019 12:59:23 +0800 Subject: [PATCH 3/3] Collect occurrences of for mismatched braces diagnostic Change-Id: I20ba0b62308370ee961141fa1aefc4b9c9f0cb3a --- src/libsyntax/parse/lexer/tokentrees.rs | 2 +- .../parser/mismatched-delim-brace-empty-block.rs | 4 +++- .../mismatched-delim-brace-empty-block.stderr | 15 +++++++++------ 3 files changed, 13 insertions(+), 8 deletions(-) diff --git a/src/libsyntax/parse/lexer/tokentrees.rs b/src/libsyntax/parse/lexer/tokentrees.rs index b088d160b923e..b4dd23c9f9b0f 100644 --- a/src/libsyntax/parse/lexer/tokentrees.rs +++ b/src/libsyntax/parse/lexer/tokentrees.rs @@ -126,7 +126,7 @@ impl<'a> TokenTreesReader<'a> { let (open_brace, open_brace_span) = self.open_braces.pop().unwrap(); let close_brace_span = self.token.span; - if close_brace_span.lo() == open_brace_span.hi() { + if tts.is_empty() { let empty_block_span = open_brace_span.to(close_brace_span); self.last_delim_empty_block_spans.insert(delim, empty_block_span); } diff --git a/src/test/ui/parser/mismatched-delim-brace-empty-block.rs b/src/test/ui/parser/mismatched-delim-brace-empty-block.rs index bcc95c09e1e99..0f5a2cb09ecc4 100644 --- a/src/test/ui/parser/mismatched-delim-brace-empty-block.rs +++ b/src/test/ui/parser/mismatched-delim-brace-empty-block.rs @@ -1,3 +1,5 @@ -fn main() {} +fn main() { + +} let _ = (); } //~ ERROR unexpected close delimiter diff --git a/src/test/ui/parser/mismatched-delim-brace-empty-block.stderr b/src/test/ui/parser/mismatched-delim-brace-empty-block.stderr index 82fe8930c325f..5ae5fc91a4e8a 100644 --- a/src/test/ui/parser/mismatched-delim-brace-empty-block.stderr +++ b/src/test/ui/parser/mismatched-delim-brace-empty-block.stderr @@ -1,11 +1,14 @@ error: unexpected close delimiter: `}` - --> $DIR/mismatched-delim-brace-empty-block.rs:3:1 + --> $DIR/mismatched-delim-brace-empty-block.rs:5:1 | -LL | fn main() {} - | -- this block is empty, you might have not meant to close it -LL | let _ = (); -LL | } - | ^ unexpected close delimiter +LL | fn main() { + | ___________- +LL | | +LL | | } + | |_- this block is empty, you might have not meant to close it +LL | let _ = (); +LL | } + | ^ unexpected close delimiter error: aborting due to previous error