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Do not recover when parsing stmt in cfg-eval. #111054

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Merged
merged 1 commit into from
May 18, 2023
Merged

Do not recover when parsing stmt in cfg-eval. #111054

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4 changes: 3 additions & 1 deletion compiler/rustc_builtin_macros/src/cfg_eval.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -166,7 +166,9 @@ impl CfgEval<'_, '_> {
))
},
Annotatable::Stmt(_) => |parser| {
Ok(Annotatable::Stmt(P(parser.parse_stmt(ForceCollect::Yes)?.unwrap())))
Ok(Annotatable::Stmt(P(parser
.parse_stmt_without_recovery(false, ForceCollect::Yes)?
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Not that familiar with the macro expansion code, so feel free to re-assign.

But I'm wondering why we even get into the expand call if the parse for the Annotatable failed in the first place. If I understand this correctly this parse is a re-parse (we also get a duplicated error message in the test). Why can't we prevent this to be called when the first parse failed?

.unwrap())))
},
Annotatable::Expr(_) => {
|parser| Ok(Annotatable::Expr(parser.parse_expr_force_collect()?))
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3 changes: 2 additions & 1 deletion compiler/rustc_parse/src/parser/stmt.rs
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Expand Up @@ -37,7 +37,8 @@ impl<'a> Parser<'a> {

/// If `force_collect` is [`ForceCollect::Yes`], forces collection of tokens regardless of whether
/// or not we have attributes
pub(crate) fn parse_stmt_without_recovery(
// Public for `cfg_eval` macro expansion.
pub fn parse_stmt_without_recovery(
&mut self,
capture_semi: bool,
force_collect: ForceCollect,
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13 changes: 13 additions & 0 deletions tests/ui/cfg/cfg-stmt-recovery.rs
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@@ -0,0 +1,13 @@
// Verify that we do not ICE when failing to parse a statement in `cfg_eval`.

#![feature(cfg_eval)]
#![feature(stmt_expr_attributes)]

#[cfg_eval]
fn main() {
#[cfg_eval]
let _ = #[cfg(FALSE)] 0;
//~^ ERROR removing an expression is not supported in this position
//~| ERROR expected expression, found `;`
//~| ERROR removing an expression is not supported in this position
}
20 changes: 20 additions & 0 deletions tests/ui/cfg/cfg-stmt-recovery.stderr
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@@ -0,0 +1,20 @@
error: removing an expression is not supported in this position
--> $DIR/cfg-stmt-recovery.rs:9:13
|
LL | let _ = #[cfg(FALSE)] 0;
| ^^^^^^^^^^^^^

error: expected expression, found `;`
--> $DIR/cfg-stmt-recovery.rs:9:28
|
LL | let _ = #[cfg(FALSE)] 0;
| ^ expected expression

error: removing an expression is not supported in this position
--> $DIR/cfg-stmt-recovery.rs:9:13
|
LL | let _ = #[cfg(FALSE)] 0;
| ^^^^^^^^^^^^^

error: aborting due to 3 previous errors