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Prevent conversion of empty tuples to unit structs

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Fixes #1408
This commit is contained in:
Aaron Lobb 2017-03-24 23:58:34 -07:00
parent 488c0b9546
commit 548de69d2d
2 changed files with 59 additions and 47 deletions
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93
src/patterns.rs
View File

@ -260,55 +260,54 @@ fn rewrite_tuple_pat(pats: &[ptr::P<ast::Pat>],
}
if pat_vec.is_empty() {
path_str
return Some(format!("{}()", try_opt!(path_str)));
}
// add comma if `(x,)`
let add_comma = path_str.is_none() && pat_vec.len() == 1 && dotdot_pos.is_none();
let path_len = path_str.as_ref().map(|p| p.len()).unwrap_or(0);
// 2 = "()".len(), 3 = "(,)".len()
let nested_shape = try_opt!(shape.sub_width(path_len + if add_comma { 3 } else { 2 }));
// 1 = "(".len()
let nested_shape = nested_shape.visual_indent(path_len + 1);
let mut items: Vec<_> = itemize_list(context.codemap,
pat_vec.iter(),
if add_comma { ",)" } else { ")" },
|item| item.span().lo,
|item| item.span().hi,
|item| item.rewrite(context, nested_shape),
context.codemap.span_after(span, "("),
span.hi - BytePos(1))
.collect();
// Condense wildcard string suffix into a single ..
let wildcard_suffix_len = count_wildcard_suffix_len(&items);
let list = if context.config.condense_wildcard_suffices && wildcard_suffix_len >= 2 {
let new_item_count = 1 + pats.len() - wildcard_suffix_len;
items[new_item_count - 1].item = Some("..".to_owned());
let da_iter = items.into_iter().take(new_item_count);
try_opt!(format_item_list(da_iter, nested_shape, context.config))
} else {
// add comma if `(x,)`
let add_comma = path_str.is_none() && pat_vec.len() == 1 && dotdot_pos.is_none();
try_opt!(format_item_list(items.into_iter(), nested_shape, context.config))
};
let path_len = path_str.as_ref().map(|p| p.len()).unwrap_or(0);
// 2 = "()".len(), 3 = "(,)".len()
let nested_shape = try_opt!(shape.sub_width(path_len + if add_comma { 3 } else { 2 }));
// 1 = "(".len()
let nested_shape = nested_shape.visual_indent(path_len + 1);
let mut items: Vec<_> = itemize_list(context.codemap,
pat_vec.iter(),
if add_comma { ",)" } else { ")" },
|item| item.span().lo,
|item| item.span().hi,
|item| item.rewrite(context, nested_shape),
context.codemap.span_after(span, "("),
span.hi - BytePos(1))
.collect();
// Condense wildcard string suffix into a single ..
let wildcard_suffix_len = count_wildcard_suffix_len(&items);
let list = if context.config.condense_wildcard_suffices && wildcard_suffix_len >= 2 {
let new_item_count = 1 + pats.len() - wildcard_suffix_len;
items[new_item_count - 1].item = Some("..".to_owned());
let da_iter = items.into_iter().take(new_item_count);
try_opt!(format_item_list(da_iter, nested_shape, context.config))
} else {
try_opt!(format_item_list(items.into_iter(), nested_shape, context.config))
};
match path_str {
Some(path_str) => {
Some(if context.config.spaces_within_parens {
format!("{}( {} )", path_str, list)
} else {
format!("{}({})", path_str, list)
})
}
None => {
let comma = if add_comma { "," } else { "" };
Some(if context.config.spaces_within_parens {
format!("( {}{} )", list, comma)
} else {
format!("({}{})", list, comma)
})
}
match path_str {
Some(path_str) => {
Some(if context.config.spaces_within_parens {
format!("{}( {} )", path_str, list)
} else {
format!("{}({})", path_str, list)
})
}
None => {
let comma = if add_comma { "," } else { "" };
Some(if context.config.spaces_within_parens {
format!("( {}{} )", list, comma)
} else {
format!("({}{})", list, comma)
})
}
}
}

13
tests/target/empty-tuple-no-conversion-to-unit-struct.rs Normal file
View File

@ -0,0 +1,13 @@
enum TestEnum {
Arm1(),
Arm2,
}
fn foo() {
let test = TestEnum::Arm1;
match test {
TestEnum::Arm1() => {}
TestEnum::Arm2 => {}
}
}