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Warn users about || in let chain expressions

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Caio 2022-03-09 15:04:09 -03:00
parent 10dccdc7fc
commit 915f9a599c
3 changed files with 179 additions and 96 deletions
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70
compiler/rustc_ast_passes/src/ast_validation.rs
View file

@ -64,8 +64,8 @@ struct AstValidator<'a> {
/// certain positions.
is_assoc_ty_bound_banned: bool,
/// Used to allow `let` expressions in certain syntactic locations.
is_let_allowed: bool,
/// See [ForbiddenLetReason]
forbidden_let_reason: Option<ForbiddenLetReason>,
lint_buffer: &'a mut LintBuffer,
}
@ -103,20 +103,28 @@ impl<'a> AstValidator<'a> {
self.is_tilde_const_allowed = old;
}
fn with_let_allowed(&mut self, allowed: bool, f: impl FnOnce(&mut Self, bool)) {
let old = mem::replace(&mut self.is_let_allowed, allowed);
fn with_let_management(
&mut self,
forbidden_let_reason: Option<ForbiddenLetReason>,
f: impl FnOnce(&mut Self, Option<ForbiddenLetReason>),
) {
let old = mem::replace(&mut self.forbidden_let_reason, forbidden_let_reason);
f(self, old);
self.is_let_allowed = old;
self.forbidden_let_reason = old;
}
/// Emits an error banning the `let` expression provided in the given location.
fn ban_let_expr(&self, expr: &'a Expr) {
fn ban_let_expr(&self, expr: &'a Expr, forbidden_let_reason: ForbiddenLetReason) {
let sess = &self.session;
if sess.opts.unstable_features.is_nightly_build() {
sess.struct_span_err(expr.span, "`let` expressions are not supported here")
.note("only supported directly in conditions of `if`- and `while`-expressions")
.note("as well as when nested within `&&` and parentheses in those conditions")
.emit();
let err = "`let` expressions are not supported here";
let mut diag = sess.struct_span_err(expr.span, err);
diag.note("only supported directly in conditions of `if` and `while` expressions");
diag.note("as well as when nested within `&&` and parentheses in those conditions");
if let ForbiddenLetReason::ForbiddenWithOr(span) = forbidden_let_reason {
diag.span_note(span, "`||` operators are not allowed in let chain expressions");
}
diag.emit();
} else {
sess.struct_span_err(expr.span, "expected expression, found statement (`let`)")
.note("variable declaration using `let` is a statement")
@ -988,39 +996,48 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
}
fn visit_expr(&mut self, expr: &'a Expr) {
self.with_let_allowed(false, |this, let_allowed| match &expr.kind {
self.with_let_management(Some(ForbiddenLetReason::GenericForbidden), |this, forbidden_let_reason| {
match &expr.kind {
ExprKind::Binary(Spanned { node: BinOpKind::Or, span }, lhs, rhs) => {
let forbidden_let_reason = Some(ForbiddenLetReason::ForbiddenWithOr(*span));
this.with_let_management(forbidden_let_reason, |this, _| this.visit_expr(lhs));
this.with_let_management(forbidden_let_reason, |this, _| this.visit_expr(rhs));
}
ExprKind::If(cond, then, opt_else) => {
this.visit_block(then);
walk_list!(this, visit_expr, opt_else);
this.with_let_allowed(true, |this, _| this.visit_expr(cond));
this.with_let_management(None, |this, _| this.visit_expr(cond));
return;
}
ExprKind::Let(..) if !let_allowed => this.ban_let_expr(expr),
ExprKind::Match(expr, arms) => {
this.visit_expr(expr);
ExprKind::Let(..) if let Some(elem) = forbidden_let_reason => {
this.ban_let_expr(expr, elem);
},
ExprKind::Match(scrutinee, arms) => {
this.visit_expr(scrutinee);
for arm in arms {
this.visit_expr(&arm.body);
this.visit_pat(&arm.pat);
walk_list!(this, visit_attribute, &arm.attrs);
if let Some(ref guard) = arm.guard {
if let ExprKind::Let(_, ref expr, _) = guard.kind {
this.with_let_allowed(true, |this, _| this.visit_expr(expr));
if let Some(guard) = &arm.guard && let ExprKind::Let(_, guard_expr, _) = &guard.kind {
this.with_let_management(None, |this, _| {
this.visit_expr(guard_expr)
});
return;
}
}
}
}
ExprKind::Paren(_) | ExprKind::Binary(Spanned { node: BinOpKind::And, .. }, ..) => {
this.with_let_allowed(let_allowed, |this, _| visit::walk_expr(this, expr));
this.with_let_management(forbidden_let_reason, |this, _| visit::walk_expr(this, expr));
return;
}
ExprKind::While(cond, then, opt_label) => {
walk_list!(this, visit_label, opt_label);
this.visit_block(then);
this.with_let_allowed(true, |this, _| this.visit_expr(cond));
this.with_let_management(None, |this, _| this.visit_expr(cond));
return;
}
_ => visit::walk_expr(this, expr),
}
});
}
@ -1772,10 +1789,19 @@ pub fn check_crate(session: &Session, krate: &Crate, lints: &mut LintBuffer) ->
is_tilde_const_allowed: false,
is_impl_trait_banned: false,
is_assoc_ty_bound_banned: false,
is_let_allowed: false,
forbidden_let_reason: Some(ForbiddenLetReason::GenericForbidden),
lint_buffer: lints,
};
visit::walk_crate(&mut validator, krate);
validator.has_proc_macro_decls
}
/// Used to forbid `let` expressions in certain syntactic locations.
#[derive(Clone, Copy)]
enum ForbiddenLetReason {
/// A let chain with the `||` operator
ForbiddenWithOr(Span),
/// `let` is not valid and the source environment is not important
GenericForbidden,
}

6
compiler/rustc_ast_passes/src/lib.rs
View file

@ -4,11 +4,13 @@
//!
//! The crate also contains other misc AST visitors, e.g. `node_count` and `show_span`.
#![feature(iter_is_partitioned)]
#![allow(rustc::potential_query_instability)]
#![feature(box_patterns)]
#![feature(if_let_guard)]
#![feature(iter_is_partitioned)]
#![feature(let_chains)]
#![feature(let_else)]
#![recursion_limit = "256"]
#![allow(rustc::potential_query_instability)]
pub mod ast_validation;
pub mod feature_gate;

165
src/test/ui/rfc-2497-if-let-chains/disallowed-positions.stderr
View file

@ -15,7 +15,7 @@ error: `let` expressions are not supported here
LL | if &let 0 = 0 {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -24,7 +24,7 @@ error: `let` expressions are not supported here
LL | if !let 0 = 0 {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -33,7 +33,7 @@ error: `let` expressions are not supported here
LL | if *let 0 = 0 {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -42,7 +42,7 @@ error: `let` expressions are not supported here
LL | if -let 0 = 0 {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -51,7 +51,7 @@ error: `let` expressions are not supported here
LL | if (let 0 = 0)? {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -60,8 +60,13 @@ error: `let` expressions are not supported here
LL | if true || let 0 = 0 {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
note: `||` operators are not allowed in let chain expressions
--> $DIR/disallowed-positions.rs:47:13
|
LL | if true || let 0 = 0 {}
| ^^
error: `let` expressions are not supported here
--> $DIR/disallowed-positions.rs:48:17
@ -69,8 +74,13 @@ error: `let` expressions are not supported here
LL | if (true || let 0 = 0) {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
note: `||` operators are not allowed in let chain expressions
--> $DIR/disallowed-positions.rs:48:14
|
LL | if (true || let 0 = 0) {}
| ^^
error: `let` expressions are not supported here
--> $DIR/disallowed-positions.rs:49:25
@ -78,8 +88,13 @@ error: `let` expressions are not supported here
LL | if true && (true || let 0 = 0) {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
note: `||` operators are not allowed in let chain expressions
--> $DIR/disallowed-positions.rs:49:22
|
LL | if true && (true || let 0 = 0) {}
| ^^
error: `let` expressions are not supported here
--> $DIR/disallowed-positions.rs:50:25
@ -87,8 +102,13 @@ error: `let` expressions are not supported here
LL | if true || (true && let 0 = 0) {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
note: `||` operators are not allowed in let chain expressions
--> $DIR/disallowed-positions.rs:50:13
|
LL | if true || (true && let 0 = 0) {}
| ^^
error: `let` expressions are not supported here
--> $DIR/disallowed-positions.rs:53:12
@ -96,7 +116,7 @@ error: `let` expressions are not supported here
LL | if x = let 0 = 0 {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -105,7 +125,7 @@ error: `let` expressions are not supported here
LL | if true..(let 0 = 0) {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -114,7 +134,7 @@ error: `let` expressions are not supported here
LL | if ..(let 0 = 0) {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -123,7 +143,7 @@ error: `let` expressions are not supported here
LL | if (let 0 = 0).. {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -132,7 +152,7 @@ error: `let` expressions are not supported here
LL | if let Range { start: _, end: _ } = true..true && false {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -141,7 +161,7 @@ error: `let` expressions are not supported here
LL | if let Range { start: _, end: _ } = true..true || false {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -150,7 +170,7 @@ error: `let` expressions are not supported here
LL | if let Range { start: F, end } = F..|| true {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -159,7 +179,7 @@ error: `let` expressions are not supported here
LL | if let Range { start: true, end } = t..&&false {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -168,7 +188,7 @@ error: `let` expressions are not supported here
LL | if let true = let true = true {}
| ^^^^^^^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -177,7 +197,7 @@ error: `let` expressions are not supported here
LL | while &let 0 = 0 {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -186,7 +206,7 @@ error: `let` expressions are not supported here
LL | while !let 0 = 0 {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -195,7 +215,7 @@ error: `let` expressions are not supported here
LL | while *let 0 = 0 {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -204,7 +224,7 @@ error: `let` expressions are not supported here
LL | while -let 0 = 0 {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -213,7 +233,7 @@ error: `let` expressions are not supported here
LL | while (let 0 = 0)? {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -222,8 +242,13 @@ error: `let` expressions are not supported here
LL | while true || let 0 = 0 {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
note: `||` operators are not allowed in let chain expressions
--> $DIR/disallowed-positions.rs:111:16
|
LL | while true || let 0 = 0 {}
| ^^
error: `let` expressions are not supported here
--> $DIR/disallowed-positions.rs:112:20
@ -231,8 +256,13 @@ error: `let` expressions are not supported here
LL | while (true || let 0 = 0) {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
note: `||` operators are not allowed in let chain expressions
--> $DIR/disallowed-positions.rs:112:17
|
LL | while (true || let 0 = 0) {}
| ^^
error: `let` expressions are not supported here
--> $DIR/disallowed-positions.rs:113:28
@ -240,8 +270,13 @@ error: `let` expressions are not supported here
LL | while true && (true || let 0 = 0) {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
note: `||` operators are not allowed in let chain expressions
--> $DIR/disallowed-positions.rs:113:25
|
LL | while true && (true || let 0 = 0) {}
| ^^
error: `let` expressions are not supported here
--> $DIR/disallowed-positions.rs:114:28
@ -249,8 +284,13 @@ error: `let` expressions are not supported here
LL | while true || (true && let 0 = 0) {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
note: `||` operators are not allowed in let chain expressions
--> $DIR/disallowed-positions.rs:114:16
|
LL | while true || (true && let 0 = 0) {}
| ^^
error: `let` expressions are not supported here
--> $DIR/disallowed-positions.rs:117:15
@ -258,7 +298,7 @@ error: `let` expressions are not supported here
LL | while x = let 0 = 0 {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -267,7 +307,7 @@ error: `let` expressions are not supported here
LL | while true..(let 0 = 0) {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -276,7 +316,7 @@ error: `let` expressions are not supported here
LL | while ..(let 0 = 0) {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -285,7 +325,7 @@ error: `let` expressions are not supported here
LL | while (let 0 = 0).. {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -294,7 +334,7 @@ error: `let` expressions are not supported here
LL | while let Range { start: _, end: _ } = true..true && false {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -303,7 +343,7 @@ error: `let` expressions are not supported here
LL | while let Range { start: _, end: _ } = true..true || false {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -312,7 +352,7 @@ error: `let` expressions are not supported here
LL | while let Range { start: F, end } = F..|| true {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -321,7 +361,7 @@ error: `let` expressions are not supported here
LL | while let Range { start: true, end } = t..&&false {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -330,7 +370,7 @@ error: `let` expressions are not supported here
LL | while let true = let true = true {}
| ^^^^^^^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -339,7 +379,7 @@ error: `let` expressions are not supported here
LL | &let 0 = 0;
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -348,7 +388,7 @@ error: `let` expressions are not supported here
LL | !let 0 = 0;
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -357,7 +397,7 @@ error: `let` expressions are not supported here
LL | *let 0 = 0;
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -366,7 +406,7 @@ error: `let` expressions are not supported here
LL | -let 0 = 0;
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -375,7 +415,7 @@ error: `let` expressions are not supported here
LL | (let 0 = 0)?;
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -384,8 +424,13 @@ error: `let` expressions are not supported here
LL | true || let 0 = 0;
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
note: `||` operators are not allowed in let chain expressions
--> $DIR/disallowed-positions.rs:184:10
|
LL | true || let 0 = 0;
| ^^
error: `let` expressions are not supported here
--> $DIR/disallowed-positions.rs:185:14
@ -393,8 +438,13 @@ error: `let` expressions are not supported here
LL | (true || let 0 = 0);
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
note: `||` operators are not allowed in let chain expressions
--> $DIR/disallowed-positions.rs:185:11
|
LL | (true || let 0 = 0);
| ^^
error: `let` expressions are not supported here
--> $DIR/disallowed-positions.rs:186:22
@ -402,8 +452,13 @@ error: `let` expressions are not supported here
LL | true && (true || let 0 = 0);
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
note: `||` operators are not allowed in let chain expressions
--> $DIR/disallowed-positions.rs:186:19
|
LL | true && (true || let 0 = 0);
| ^^
error: `let` expressions are not supported here
--> $DIR/disallowed-positions.rs:189:9
@ -411,7 +466,7 @@ error: `let` expressions are not supported here
LL | x = let 0 = 0;
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -420,7 +475,7 @@ error: `let` expressions are not supported here
LL | true..(let 0 = 0);
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -429,7 +484,7 @@ error: `let` expressions are not supported here
LL | ..(let 0 = 0);
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -438,7 +493,7 @@ error: `let` expressions are not supported here
LL | (let 0 = 0)..;
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -447,7 +502,7 @@ error: `let` expressions are not supported here
LL | (let Range { start: _, end: _ } = true..true || false);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -456,7 +511,7 @@ error: `let` expressions are not supported here
LL | (let true = let true = true);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -465,7 +520,7 @@ error: `let` expressions are not supported here
LL | &let 0 = 0
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -474,7 +529,7 @@ error: `let` expressions are not supported here
LL | true && let 1 = 1
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -483,7 +538,7 @@ error: `let` expressions are not supported here
LL | true && let 1 = 1
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -492,7 +547,7 @@ error: `let` expressions are not supported here
LL | true && let 1 = 1
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error: `let` expressions are not supported here
@ -501,7 +556,7 @@ error: `let` expressions are not supported here
LL | true && let 1 = 1
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if`- and `while`-expressions
= note: only supported directly in conditions of `if` and `while` expressions
= note: as well as when nested within `&&` and parentheses in those conditions
error[E0308]: mismatched types