diff options
Diffstat (limited to 'src/libsyntax/parse/diagnostics.rs')
| -rw-r--r-- | src/libsyntax/parse/diagnostics.rs | 118 |
1 files changed, 81 insertions, 37 deletions
diff --git a/src/libsyntax/parse/diagnostics.rs b/src/libsyntax/parse/diagnostics.rs index 39cb5042fbc..9eb6aa303b0 100644 --- a/src/libsyntax/parse/diagnostics.rs +++ b/src/libsyntax/parse/diagnostics.rs @@ -14,7 +14,7 @@ use crate::ThinVec; use crate::util::parser::AssocOp; use errors::{Applicability, DiagnosticBuilder, DiagnosticId}; use rustc_data_structures::fx::FxHashSet; -use syntax_pos::{Span, DUMMY_SP, MultiSpan}; +use syntax_pos::{Span, DUMMY_SP, MultiSpan, SpanSnippetError}; use log::{debug, trace}; use std::mem; @@ -199,6 +199,10 @@ impl<'a> Parser<'a> { &self.sess.span_diagnostic } + crate fn span_to_snippet(&self, span: Span) -> Result<String, SpanSnippetError> { + self.sess.source_map().span_to_snippet(span) + } + crate fn expected_ident_found(&self) -> DiagnosticBuilder<'a> { let mut err = self.struct_span_err( self.token.span, @@ -549,8 +553,10 @@ impl<'a> Parser<'a> { ExprKind::Binary(op, _, _) if op.node.is_comparison() => { // respan to include both operators let op_span = op.span.to(self.token.span); - let mut err = self.diagnostic().struct_span_err(op_span, - "chained comparison operators require parentheses"); + let mut err = self.struct_span_err( + op_span, + "chained comparison operators require parentheses", + ); if op.node == BinOpKind::Lt && *outer_op == AssocOp::Less || // Include `<` to provide this recommendation *outer_op == AssocOp::Greater // even in a case like the following: @@ -717,8 +723,6 @@ impl<'a> Parser<'a> { path.span = ty_span.to(self.prev_span); let ty_str = self - .sess - .source_map() .span_to_snippet(ty_span) .unwrap_or_else(|_| pprust::ty_to_string(&ty)); self.diagnostic() @@ -889,7 +893,7 @@ impl<'a> Parser<'a> { err.span_label(await_sp, "while parsing this incorrect await expression"); err })?; - let expr_str = self.sess.source_map().span_to_snippet(expr.span) + let expr_str = self.span_to_snippet(expr.span) .unwrap_or_else(|_| pprust::expr_to_string(&expr)); let suggestion = format!("{}.await{}", expr_str, if is_question { "?" } else { "" }); let sp = lo.to(expr.span); @@ -923,6 +927,48 @@ impl<'a> Parser<'a> { } } + /// Recover a situation like `for ( $pat in $expr )` + /// and suggest writing `for $pat in $expr` instead. + /// + /// This should be called before parsing the `$block`. + crate fn recover_parens_around_for_head( + &mut self, + pat: P<Pat>, + expr: &Expr, + begin_paren: Option<Span>, + ) -> P<Pat> { + match (&self.token.kind, begin_paren) { + (token::CloseDelim(token::Paren), Some(begin_par_sp)) => { + self.bump(); + + let pat_str = self + // Remove the `(` from the span of the pattern: + .span_to_snippet(pat.span.trim_start(begin_par_sp).unwrap()) + .unwrap_or_else(|_| pprust::pat_to_string(&pat)); + + self.struct_span_err(self.prev_span, "unexpected closing `)`") + .span_label(begin_par_sp, "opening `(`") + .span_suggestion( + begin_par_sp.to(self.prev_span), + "remove parenthesis in `for` loop", + format!("{} in {}", pat_str, pprust::expr_to_string(&expr)), + // With e.g. `for (x) in y)` this would replace `(x) in y)` + // with `x) in y)` which is syntactically invalid. + // However, this is prevented before we get here. + Applicability::MachineApplicable, + ) + .emit(); + + // Unwrap `(pat)` into `pat` to avoid the `unused_parens` lint. + pat.and_then(|pat| match pat.node { + PatKind::Paren(pat) => pat, + _ => P(pat), + }) + } + _ => pat, + } + } + crate fn could_ascription_be_path(&self, node: &ast::ExprKind) -> bool { self.token.is_ident() && if let ast::ExprKind::Path(..) = node { true } else { false } && @@ -1105,17 +1151,14 @@ impl<'a> Parser<'a> { crate fn check_for_for_in_in_typo(&mut self, in_span: Span) { if self.eat_keyword(kw::In) { // a common typo: `for _ in in bar {}` - let mut err = self.sess.span_diagnostic.struct_span_err( - self.prev_span, - "expected iterable, found keyword `in`", - ); - err.span_suggestion_short( - in_span.until(self.prev_span), - "remove the duplicated `in`", - String::new(), - Applicability::MachineApplicable, - ); - err.emit(); + self.struct_span_err(self.prev_span, "expected iterable, found keyword `in`") + .span_suggestion_short( + in_span.until(self.prev_span), + "remove the duplicated `in`", + String::new(), + Applicability::MachineApplicable, + ) + .emit(); } } @@ -1128,12 +1171,12 @@ impl<'a> Parser<'a> { crate fn eat_incorrect_doc_comment_for_arg_type(&mut self) { if let token::DocComment(_) = self.token.kind { - let mut err = self.diagnostic().struct_span_err( + self.struct_span_err( self.token.span, "documentation comments cannot be applied to a function parameter's type", - ); - err.span_label(self.token.span, "doc comments are not allowed here"); - err.emit(); + ) + .span_label(self.token.span, "doc comments are not allowed here") + .emit(); self.bump(); } else if self.token == token::Pound && self.look_ahead(1, |t| { *t == token::OpenDelim(token::Bracket) @@ -1145,12 +1188,12 @@ impl<'a> Parser<'a> { } let sp = lo.to(self.token.span); self.bump(); - let mut err = self.diagnostic().struct_span_err( + self.struct_span_err( sp, "attributes cannot be applied to a function parameter's type", - ); - err.span_label(sp, "attributes are not allowed here"); - err.emit(); + ) + .span_label(sp, "attributes are not allowed here") + .emit(); } } @@ -1206,18 +1249,19 @@ impl<'a> Parser<'a> { self.expect(&token::Colon)?; let ty = self.parse_ty()?; - let mut err = self.diagnostic().struct_span_err_with_code( - pat.span, - "patterns aren't allowed in methods without bodies", - DiagnosticId::Error("E0642".into()), - ); - err.span_suggestion_short( - pat.span, - "give this argument a name or use an underscore to ignore it", - "_".to_owned(), - Applicability::MachineApplicable, - ); - err.emit(); + self.diagnostic() + .struct_span_err_with_code( + pat.span, + "patterns aren't allowed in methods without bodies", + DiagnosticId::Error("E0642".into()), + ) + .span_suggestion_short( + pat.span, + "give this argument a name or use an underscore to ignore it", + "_".to_owned(), + Applicability::MachineApplicable, + ) + .emit(); // Pretend the pattern is `_`, to avoid duplicate errors from AST validation. let pat = P(Pat { |