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parse_if_expr: recover on attributes

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This commit is contained in:
Mazdak Farrokhzad 2020-03-07 17:16:29 +01:00
parent ba3ae46de9
commit 458383dd33
9 changed files with 98 additions and 64 deletions
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1
src/librustc_parse/lib.rs
View File

@ -2,6 +2,7 @@
#![feature(bool_to_option)]
#![feature(crate_visibility_modifier)]
#![feature(bindings_after_at)]
use rustc_ast::ast;
use rustc_ast::token::{self, Nonterminal};

43
src/librustc_parse/parser/expr.rs
View File

@ -1514,13 +1514,16 @@ impl<'a> Parser<'a> {
let thn = if self.eat_keyword(kw::Else) || !cond.returns() {
self.error_missing_if_cond(lo, cond.span)
} else {
let attrs = self.parse_outer_attributes()?; // For recovery.
let not_block = self.token != token::OpenDelim(token::Brace);
self.parse_block().map_err(|mut err| {
let block = self.parse_block().map_err(|mut err| {
if not_block {
err.span_label(lo, "this `if` expression has a condition, but no block");
}
err
})?
})?;
self.error_on_if_block_attrs(lo, false, block.span, &attrs);
block
};
let els = if self.eat_keyword(kw::Else) { Some(self.parse_else_expr()?) } else { None };
Ok(self.mk_expr(lo.to(self.prev_token.span), ExprKind::If(cond, thn, els), attrs))
@ -1562,12 +1565,40 @@ impl<'a> Parser<'a> {
/// Parses an `else { ... }` expression (`else` token already eaten).
fn parse_else_expr(&mut self) -> PResult<'a, P<Expr>> {
if self.eat_keyword(kw::If) {
self.parse_if_expr(AttrVec::new())
let ctx_span = self.prev_token.span; // `else`
let attrs = self.parse_outer_attributes()?; // For recovery.
let expr = if self.eat_keyword(kw::If) {
self.parse_if_expr(AttrVec::new())?
} else {
let blk = self.parse_block()?;
Ok(self.mk_expr(blk.span, ExprKind::Block(blk, None), AttrVec::new()))
}
self.mk_expr(blk.span, ExprKind::Block(blk, None), AttrVec::new())
};
self.error_on_if_block_attrs(ctx_span, true, expr.span, &attrs);
Ok(expr)
}
fn error_on_if_block_attrs(
&self,
ctx_span: Span,
is_ctx_else: bool,
branch_span: Span,
attrs: &[ast::Attribute],
) {
let (span, last) = match attrs {
[] => return,
[x0 @ xn] | [x0, .., xn] => (x0.span.to(xn.span), xn.span),
};
let ctx = if is_ctx_else { "else" } else { "if" };
self.struct_span_err(last, "outer attributes are not allowed on `if` and `else` branches")
.span_label(branch_span, "the attributes are attached to this branch")
.span_label(ctx_span, format!("the branch belongs to this `{}`", ctx))
.span_suggestion(
span,
"remove the attributes",
String::new(),
Applicability::MachineApplicable,
)
.emit();
}
/// Parses `for <src_pat> in <src_expr> <src_loop_block>` (`for` token already eaten).

3
src/librustc_parse/parser/item.rs
View File

@ -352,8 +352,7 @@ impl<'a> Parser<'a> {
fn recover_attrs_no_item(&mut self, attrs: &[Attribute]) -> PResult<'a, ()> {
let (start, end) = match attrs {
[] => return Ok(()),
[x0] => (x0, x0),
[x0, .., xn] => (x0, xn),
[x0 @ xn] | [x0, .., xn] => (x0, xn),
};
let msg = if end.is_doc_comment() {
"expected item after doc comment"

2
src/test/ui/if-attrs/else-attrs.rs
View File

@ -8,7 +8,7 @@ fn if_else_parse_error() {
#[cfg(FALSE)]
fn else_attr_ifparse_error() {
if true {
} else #[attr] if false { //~ ERROR expected
} else #[attr] if false { //~ ERROR outer attributes are not allowed
} else {
}
}

19
src/test/ui/if-attrs/else-attrs.stderr
View File

@ -4,18 +4,17 @@ error: expected expression, found keyword `else`
LL | } #[attr] else if false {
| ^^^^ expected expression
error: expected `{`, found `#`
error: outer attributes are not allowed on `if` and `else` branches
--> $DIR/else-attrs.rs:11:12
|
LL | } else #[attr] if false {
| ^ expected `{`
|
help: try placing this code inside a block
|
LL | } else #[attr] { if false {
LL | } else {
LL | } }
|
LL | } else #[attr] if false {
| _______----_^^^^^^^_-
| | | |
| | | help: remove the attributes
| | the branch belongs to this `else`
LL | | } else {
LL | | }
| |_____- the attributes are attached to this branch
error: expected expression, found keyword `else`
--> $DIR/else-attrs.rs:20:15

16
src/test/ui/parser/attr-stmt-expr-attr-bad.rs
View File

@ -39,35 +39,35 @@ fn main() {}
#[cfg(FALSE)] fn e() { let _ = #[attr] &mut #![attr] 0; }
//~^ ERROR an inner attribute is not permitted in this context
#[cfg(FALSE)] fn e() { let _ = if 0 #[attr] {}; }
//~^ ERROR expected `{`, found `#`
//~^ ERROR outer attributes are not allowed on `if`
#[cfg(FALSE)] fn e() { let _ = if 0 {#![attr]}; }
//~^ ERROR an inner attribute is not permitted in this context
#[cfg(FALSE)] fn e() { let _ = if 0 {} #[attr] else {}; }
//~^ ERROR expected one of
#[cfg(FALSE)] fn e() { let _ = if 0 {} else #[attr] {}; }
//~^ ERROR expected `{`, found `#`
//~^ ERROR outer attributes are not allowed on `if`
#[cfg(FALSE)] fn e() { let _ = if 0 {} else {#![attr]}; }
//~^ ERROR an inner attribute is not permitted in this context
#[cfg(FALSE)] fn e() { let _ = if 0 {} else #[attr] if 0 {}; }
//~^ ERROR expected `{`, found `#`
//~^ ERROR outer attributes are not allowed on `if`
#[cfg(FALSE)] fn e() { let _ = if 0 {} else if 0 #[attr] {}; }
//~^ ERROR expected `{`, found `#`
//~^ ERROR outer attributes are not allowed on `if`
#[cfg(FALSE)] fn e() { let _ = if 0 {} else if 0 {#![attr]}; }
//~^ ERROR an inner attribute is not permitted in this context
#[cfg(FALSE)] fn e() { let _ = if let _ = 0 #[attr] {}; }
//~^ ERROR expected `{`, found `#`
//~^ ERROR outer attributes are not allowed on `if`
#[cfg(FALSE)] fn e() { let _ = if let _ = 0 {#![attr]}; }
//~^ ERROR an inner attribute is not permitted in this context
#[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} #[attr] else {}; }
//~^ ERROR expected one of
#[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} else #[attr] {}; }
//~^ ERROR expected `{`, found `#`
//~^ ERROR outer attributes are not allowed on `if`
#[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} else {#![attr]}; }
//~^ ERROR an inner attribute is not permitted in this context
#[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} else #[attr] if let _ = 0 {}; }
//~^ ERROR expected `{`, found `#`
//~^ ERROR outer attributes are not allowed on `if`
#[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} else if let _ = 0 #[attr] {}; }
//~^ ERROR expected `{`, found `#`
//~^ ERROR outer attributes are not allowed on `if`
#[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} else if let _ = 0 {#![attr]}; }
//~^ ERROR an inner attribute is not permitted in this context

68
src/test/ui/parser/attr-stmt-expr-attr-bad.stderr
View File

@ -136,14 +136,14 @@ LL | #[cfg(FALSE)] fn e() { let _ = #[attr] &mut #![attr] 0; }
|
= note: inner attributes, like `#![no_std]`, annotate the item enclosing them, and are usually found at the beginning of source files. Outer attributes, like `#[test]`, annotate the item following them.
error: expected `{`, found `#`
error: outer attributes are not allowed on `if` and `else` branches
--> $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: `{ {} }`
| -- ^^^^^^^ -- the attributes are attached to this branch
| | |
| | expected `{`
| this `if` expression has a condition, but no block
| | help: remove the attributes
| the branch belongs to this `if`
error: an inner attribute is not permitted in this context
--> $DIR/attr-stmt-expr-attr-bad.rs:43:38
@ -159,13 +159,14 @@ error: expected one of `.`, `;`, `?`, `else`, or an operator, found `#`
LL | #[cfg(FALSE)] fn e() { let _ = if 0 {} #[attr] else {}; }
| ^ expected one of `.`, `;`, `?`, `else`, or an operator
error: expected `{`, found `#`
error: outer attributes are not allowed on `if` and `else` branches
--> $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: `{ {} }`
| |
| expected `{`
| ---- ^^^^^^^ -- the attributes are attached to this branch
| | |
| | help: remove the attributes
| the branch belongs to this `else`
error: an inner attribute is not permitted in this context
--> $DIR/attr-stmt-expr-attr-bad.rs:49:46
@ -175,22 +176,23 @@ LL | #[cfg(FALSE)] fn e() { let _ = if 0 {} else {#![attr]}; }
|
= note: inner attributes, like `#![no_std]`, annotate the item enclosing them, and are usually found at the beginning of source files. Outer attributes, like `#[test]`, annotate the item following them.
error: expected `{`, found `#`
error: outer attributes are not allowed on `if` and `else` branches
--> $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 {} }`
| |
| expected `{`
| ---- ^^^^^^^ ------- the attributes are attached to this branch
| | |
| | help: remove the attributes
| the branch belongs to this `else`
error: expected `{`, found `#`
error: outer attributes are not allowed on `if` and `else` branches
--> $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: `{ {} }`
| -- ^^^^^^^ -- the attributes are attached to this branch
| | |
| | expected `{`
| this `if` expression has a condition, but no block
| | help: remove the attributes
| the branch belongs to this `if`
error: an inner attribute is not permitted in this context
--> $DIR/attr-stmt-expr-attr-bad.rs:55:51
@ -200,14 +202,14 @@ LL | #[cfg(FALSE)] fn e() { let _ = if 0 {} else if 0 {#![attr]}; }
|
= note: inner attributes, like `#![no_std]`, annotate the item enclosing them, and are usually found at the beginning of source files. Outer attributes, like `#[test]`, annotate the item following them.
error: expected `{`, found `#`
error: outer attributes are not allowed on `if` and `else` branches
--> $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: `{ {} }`
| -- ^^^^^^^ -- the attributes are attached to this branch
| | |
| | expected `{`
| this `if` expression has a condition, but no block
| | help: remove the attributes
| the branch belongs to this `if`
error: an inner attribute is not permitted in this context
--> $DIR/attr-stmt-expr-attr-bad.rs:59:46
@ -223,13 +225,14 @@ error: expected one of `.`, `;`, `?`, `else`, or an operator, found `#`
LL | #[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} #[attr] else {}; }
| ^ expected one of `.`, `;`, `?`, `else`, or an operator
error: expected `{`, found `#`
error: outer attributes are not allowed on `if` and `else` branches
--> $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: `{ {} }`
| |
| expected `{`
| ---- ^^^^^^^ -- the attributes are attached to this branch
| | |
| | help: remove the attributes
| the branch belongs to this `else`
error: an inner attribute is not permitted in this context
--> $DIR/attr-stmt-expr-attr-bad.rs:65:54
@ -239,22 +242,23 @@ LL | #[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} else {#![attr]}; }
|
= note: inner attributes, like `#![no_std]`, annotate the item enclosing them, and are usually found at the beginning of source files. Outer attributes, like `#[test]`, annotate the item following them.
error: expected `{`, found `#`
error: outer attributes are not allowed on `if` and `else` branches
--> $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 {} }`
| |
| expected `{`
| ---- ^^^^^^^ --------------- the attributes are attached to this branch
| | |
| | help: remove the attributes
| the branch belongs to this `else`
error: expected `{`, found `#`
error: outer attributes are not allowed on `if` and `else` branches
--> $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: `{ {} }`
| -- ^^^^^^^ -- the attributes are attached to this branch
| | |
| | expected `{`
| this `if` expression has a condition, but no block
| | help: remove the attributes
| the branch belongs to this `if`
error: an inner attribute is not permitted in this context
--> $DIR/attr-stmt-expr-attr-bad.rs:71:67

2
src/test/ui/parser/doc-comment-in-if-statement.rs
View File

@ -1,5 +1,5 @@
fn main() {
if true /*!*/ {}
//~^ ERROR expected `{`, found doc comment `/*!*/`
//~^ ERROR outer attributes are not allowed on
//~| ERROR expected outer doc comment
}

8
src/test/ui/parser/doc-comment-in-if-statement.stderr
View File

@ -6,14 +6,14 @@ LL | if true /*!*/ {}
|
= note: inner doc comments like this (starting with `//!` or `/*!`) can only appear before items
error: expected `{`, found doc comment `/*!*/`
error: outer attributes are not allowed on `if` and `else` branches
--> $DIR/doc-comment-in-if-statement.rs:2:13
|
LL | if true /*!*/ {}
| -- ^^^^^ -- help: try placing this code inside a block: `{ {} }`
| -- ^^^^^ -- the attributes are attached to this branch
| | |
| | expected `{`
| this `if` expression has a condition, but no block
| | help: remove the attributes
| the branch belongs to this `if`
error: aborting due to 2 previous errors