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Do not suggest using | in let assignments #61643

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33 changes: 21 additions & 12 deletions src/libsyntax/parse/parser.rs
Original file line number Diff line number Diff line change
Expand Up @@ -3257,7 +3257,7 @@ impl<'a> Parser<'a> {
mut attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> {
// Parse: `for <src_pat> in <src_expr> <src_loop_block>`

let pat = self.parse_top_level_pat()?;
let pat = self.parse_top_level_pat(false)?;
if !self.eat_keyword(kw::In) {
let in_span = self.prev_span.between(self.span);
let mut err = self.sess.span_diagnostic
Expand Down Expand Up @@ -3509,7 +3509,7 @@ impl<'a> Parser<'a> {

let mut pats = Vec::new();
loop {
pats.push(self.parse_top_level_pat()?);
pats.push(self.parse_top_level_pat(true)?);

if self.token == token::OrOr {
let mut err = self.struct_span_err(self.span,
Expand Down Expand Up @@ -3860,7 +3860,7 @@ impl<'a> Parser<'a> {
/// A wrapper around `parse_pat` with some special error handling for the
/// "top-level" patterns in a match arm, `for` loop, `let`, &c. (in contrast
/// to subpatterns within such).
fn parse_top_level_pat(&mut self) -> PResult<'a, P<Pat>> {
fn parse_top_level_pat(&mut self, is_match_arg: bool) -> PResult<'a, P<Pat>> {
let pat = self.parse_pat(None)?;
if self.token == token::Comma {
// An unexpected comma after a top-level pattern is a clue that the
Expand All @@ -3877,20 +3877,29 @@ impl<'a> Parser<'a> {
err.cancel();
}
let seq_span = pat.span.to(self.prev_span);
let mut err = self.struct_span_err(comma_span,
"unexpected `,` in pattern");
let mut err = self.struct_span_err(
comma_span,
"unexpected `,` in pattern",
);
if let Ok(seq_snippet) = self.sess.source_map().span_to_snippet(seq_span) {
err.span_suggestion(
seq_span,
"try adding parentheses to match on a tuple..",
&format!("try adding parentheses to match on a tuple{}", if is_match_arg {
"..."
} else {
""
}),
format!("({})", seq_snippet),
Applicability::MachineApplicable
).span_suggestion(
seq_span,
"..or a vertical bar to match on multiple alternatives",
format!("{}", seq_snippet.replace(",", " |")),
Applicability::MachineApplicable
);
if is_match_arg {
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err.span_suggestion(
seq_span,
"...or a vertical bar to match on multiple alternatives",
format!("{}", seq_snippet.replace(",", " |")),
Applicability::MachineApplicable
);
}
}
return Err(err);
}
Expand Down Expand Up @@ -4149,7 +4158,7 @@ impl<'a> Parser<'a> {
/// Parses a local variable declaration.
fn parse_local(&mut self, attrs: ThinVec<Attribute>) -> PResult<'a, P<Local>> {
let lo = self.prev_span;
let pat = self.parse_top_level_pat()?;
let pat = self.parse_top_level_pat(false)?;

let (err, ty) = if self.eat(&token::Colon) {
// Save the state of the parser before parsing type normally, in case there is a `:`
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -3,11 +3,11 @@ error: unexpected `,` in pattern
|
LL | while let b1, b2, b3 = reading_frame.next().expect("there should be a start codon") {
| ^
help: try adding parentheses to match on a tuple..
help: try adding parentheses to match on a tuple...
|
LL | while let (b1, b2, b3) = reading_frame.next().expect("there should be a start codon") {
| ^^^^^^^^^^^^
help: ..or a vertical bar to match on multiple alternatives
help: ...or a vertical bar to match on multiple alternatives
|
LL | while let b1 | b2 | b3 = reading_frame.next().expect("there should be a start codon") {
| ^^^^^^^^^^^^
Expand All @@ -17,11 +17,11 @@ error: unexpected `,` in pattern
|
LL | if let b1, b2, b3 = reading_frame.next().unwrap() {
| ^
help: try adding parentheses to match on a tuple..
help: try adding parentheses to match on a tuple...
|
LL | if let (b1, b2, b3) = reading_frame.next().unwrap() {
| ^^^^^^^^^^^^
help: ..or a vertical bar to match on multiple alternatives
help: ...or a vertical bar to match on multiple alternatives
|
LL | if let b1 | b2 | b3 = reading_frame.next().unwrap() {
| ^^^^^^^^^^^^
Expand All @@ -31,11 +31,11 @@ error: unexpected `,` in pattern
|
LL | Nucleotide::Adenine, Nucleotide::Cytosine, _ => true
| ^
help: try adding parentheses to match on a tuple..
help: try adding parentheses to match on a tuple...
|
LL | (Nucleotide::Adenine, Nucleotide::Cytosine, _) => true
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
help: ..or a vertical bar to match on multiple alternatives
help: ...or a vertical bar to match on multiple alternatives
|
LL | Nucleotide::Adenine | Nucleotide::Cytosine | _ => true
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Expand All @@ -44,43 +44,19 @@ error: unexpected `,` in pattern
--> $DIR/issue-48492-tuple-destructure-missing-parens.rs:67:10
|
LL | for x, _barr_body in women.iter().map(|woman| woman.allosomes.clone()) {
| ^
help: try adding parentheses to match on a tuple..
|
LL | for (x, _barr_body) in women.iter().map(|woman| woman.allosomes.clone()) {
| ^^^^^^^^^^^^^^^
help: ..or a vertical bar to match on multiple alternatives
|
LL | for x | _barr_body in women.iter().map(|woman| woman.allosomes.clone()) {
| ^^^^^^^^^^^^^^
| -^----------- help: try adding parentheses to match on a tuple: `(x, _barr_body)`

error: unexpected `,` in pattern
--> $DIR/issue-48492-tuple-destructure-missing-parens.rs:75:10
|
LL | for x, y @ Allosome::Y(_) in men.iter().map(|man| man.allosomes.clone()) {
| ^
help: try adding parentheses to match on a tuple..
|
LL | for (x, y @ Allosome::Y(_)) in men.iter().map(|man| man.allosomes.clone()) {
| ^^^^^^^^^^^^^^^^^^^^^^^
help: ..or a vertical bar to match on multiple alternatives
|
LL | for x | y @ Allosome::Y(_) in men.iter().map(|man| man.allosomes.clone()) {
| ^^^^^^^^^^^^^^^^^^^^^^
| -^------------------- help: try adding parentheses to match on a tuple: `(x, y @ Allosome::Y(_))`

error: unexpected `,` in pattern
--> $DIR/issue-48492-tuple-destructure-missing-parens.rs:84:14
|
LL | let women, men: (Vec<Genome>, Vec<Genome>) = genomes.iter().cloned()
| ^
help: try adding parentheses to match on a tuple..
|
LL | let (women, men): (Vec<Genome>, Vec<Genome>) = genomes.iter().cloned()
| ^^^^^^^^^^^^
help: ..or a vertical bar to match on multiple alternatives
|
LL | let women | men: (Vec<Genome>, Vec<Genome>) = genomes.iter().cloned()
| ^^^^^^^^^^^
| -----^---- help: try adding parentheses to match on a tuple: `(women, men)`

error: aborting due to 6 previous errors

5 changes: 5 additions & 0 deletions src/test/ui/suggestions/issue-61573.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,5 @@
fn main() {
let a, b = x;
//~^ ERROR unexpected `,` in pattern
//~| HELP try adding parentheses to match on a tuple
}
8 changes: 8 additions & 0 deletions src/test/ui/suggestions/issue-61573.stderr
Original file line number Diff line number Diff line change
@@ -0,0 +1,8 @@
error: unexpected `,` in pattern
--> $DIR/issue-61573.rs:2:10
|
LL | let a, b = x;
| -^-- help: try adding parentheses to match on a tuple: `(a, b)`

error: aborting due to previous error