From a7e32a5319f82c19f7c8024efd3afcc1825fa5e2 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Esteban=20K=C3=BCber?= Date: Sun, 31 Aug 2025 00:42:58 +0000 Subject: [PATCH 1/3] Provide suggestion when encountering `match () { () => 1 } + match () { () => 1 }` ``` error[E0308]: mismatched types --> $DIR/expr-as-stmt.rs:69:5 | LL | match () { () => 1 } + match () { () => 1 } | ^^^^^^^^^^^^^^^^^^^^ expected `()`, found integer | help: consider using a semicolon here | LL | match () { () => 1 }; + match () { () => 1 } | + help: alternatively, parentheses are required to parse this as an expression | LL | (match () { () => 1 }) + match () { () => 1 } | + + ``` Parentheses are needed for the `match` to be unambiguously parsed as an expression and not a statement when chaining with binops that are also unops. --- compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs | 11 +++++++++++ tests/ui/parser/expr-as-stmt.stderr | 13 ++++++++++--- tests/ui/suggestions/match-needing-semi.stderr | 17 ++++++++++++++--- 3 files changed, 35 insertions(+), 6 deletions(-) diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs index 5aec50c8b5383..e70e444a53d91 100644 --- a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs +++ b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs @@ -1914,6 +1914,17 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { self.check_expr_has_type_or_error(expr, self.tcx.types.unit, |err| { if expr.can_have_side_effects() { self.suggest_semicolon_at_end(expr.span, err); + if let hir::ExprKind::Match(..) = expr.kind { + err.multipart_suggestion( + "alternatively, parentheses are required to parse this as an \ + expression", + vec![ + (expr.span.shrink_to_lo(), "(".to_string()), + (expr.span.shrink_to_hi(), ")".to_string()), + ], + Applicability::MaybeIncorrect, + ); + } } }); } diff --git a/tests/ui/parser/expr-as-stmt.stderr b/tests/ui/parser/expr-as-stmt.stderr index 577c3455a7180..562162ef3946d 100644 --- a/tests/ui/parser/expr-as-stmt.stderr +++ b/tests/ui/parser/expr-as-stmt.stderr @@ -227,9 +227,16 @@ error[E0308]: mismatched types --> $DIR/expr-as-stmt.rs:69:5 | LL | match () { () => 1 } + match () { () => 1 } - | ^^^^^^^^^^^^^^^^^^^^- help: consider using a semicolon here - | | - | expected `()`, found integer + | ^^^^^^^^^^^^^^^^^^^^ expected `()`, found integer + | +help: consider using a semicolon here + | +LL | match () { () => 1 }; + match () { () => 1 } + | + +help: alternatively, parentheses are required to parse this as an expression + | +LL | (match () { () => 1 }) + match () { () => 1 } + | + + error[E0308]: mismatched types --> $DIR/expr-as-stmt.rs:75:14 diff --git a/tests/ui/suggestions/match-needing-semi.stderr b/tests/ui/suggestions/match-needing-semi.stderr index b5f01d7038c0d..8f74997fdbee0 100644 --- a/tests/ui/suggestions/match-needing-semi.stderr +++ b/tests/ui/suggestions/match-needing-semi.stderr @@ -28,9 +28,20 @@ LL | | 4 => 1, LL | | 3 => 2, LL | | _ => 2 LL | | } - | | ^- help: consider using a semicolon here - | |_____| - | expected `()`, found integer + | |_____^ expected `()`, found integer + | +help: consider using a semicolon here + | +LL | }; + | + +help: alternatively, parentheses are required to parse this as an expression + | +LL ~ (match 3 { +LL | 4 => 1, +LL | 3 => 2, +LL | _ => 2 +LL ~ }) + | error: aborting due to 2 previous errors From f5b5e67f0f512d30cc6a5dab0ed6cf55c3905db5 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Esteban=20K=C3=BCber?= Date: Sun, 31 Aug 2025 01:43:57 +0000 Subject: [PATCH 2/3] More targeted parentheses suggestion for match statement intended as expression ``` error[E0308]: mismatched types --> $DIR/expr-as-stmt.rs:69:5 | LL | match () { () => 1 } + match () { () => 1 } | ^^^^^^^^^^^^^^^^^^^^ expected `()`, found integer | help: parentheses are required to parse this as an expression | LL | (match () { () => 1 }) + match () { () => 1 } | + + ``` --- .../rustc_hir_typeck/src/fn_ctxt/checks.rs | 30 ++++++-- tests/ui/parser/expr-as-stmt.fixed | 11 ++- tests/ui/parser/expr-as-stmt.rs | 9 +++ tests/ui/parser/expr-as-stmt.stderr | 75 +++++++++++++++++-- .../ui/suggestions/match-needing-semi.stderr | 17 +---- 5 files changed, 116 insertions(+), 26 deletions(-) diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs index e70e444a53d91..33dc56d49b499 100644 --- a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs +++ b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs @@ -1913,17 +1913,37 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { // Check with expected type of `()`. self.check_expr_has_type_or_error(expr, self.tcx.types.unit, |err| { if expr.can_have_side_effects() { - self.suggest_semicolon_at_end(expr.span, err); - if let hir::ExprKind::Match(..) = expr.kind { + let hir_id = stmt.hir_id; + if let hir::ExprKind::Match(..) = expr.kind + && let hir::Node::Block(b) = self.tcx.parent_hir_node(hir_id) + && let mut stmts = b.stmts.iter().skip_while(|s| s.hir_id != hir_id) + && let Some(_) = stmts.next() // The statement from the `match` + && let Some(next) = match (stmts.next(), b.expr) { + (Some(next), _) => match next.kind { + hir::StmtKind::Expr(next) | hir::StmtKind::Semi(next) => Some(next), + _ => None, + }, + (None, Some(next)) => Some(next), + _ => None, + } + && let hir::ExprKind::AddrOf(..) + | hir::ExprKind::Unary(..) + | hir::ExprKind::Err(_) = next.kind + { + // We have something like `match () { _ => true } && true`. Suggest + // wrapping in parentheses. We find the statement or expression + // following the `match` (`&& true`) and see if it is something that + // can reasonably be interpreted as a binop following an expression. err.multipart_suggestion( - "alternatively, parentheses are required to parse this as an \ - expression", + "parentheses are required to parse this as an expression", vec![ (expr.span.shrink_to_lo(), "(".to_string()), (expr.span.shrink_to_hi(), ")".to_string()), ], - Applicability::MaybeIncorrect, + Applicability::MachineApplicable, ); + } else { + self.suggest_semicolon_at_end(expr.span, err); } } }); diff --git a/tests/ui/parser/expr-as-stmt.fixed b/tests/ui/parser/expr-as-stmt.fixed index 0a4d62a4a0c8e..bfae55047ed1b 100644 --- a/tests/ui/parser/expr-as-stmt.fixed +++ b/tests/ui/parser/expr-as-stmt.fixed @@ -66,7 +66,7 @@ fn asteroids() -> impl FnOnce() -> bool { // https://github.com/rust-lang/rust/issues/105179 fn r#match() -> i32 { - (match () { () => 1 }) + match () { () => 1 } //~ ERROR expected expression, found `+` + ((match () { () => 1 })) + match () { () => 1 } //~ ERROR expected expression, found `+` //~^ ERROR mismatched types } @@ -76,4 +76,13 @@ fn r#unsafe() -> i32 { //~^ ERROR mismatched types } +// https://github.com/rust-lang/rust/issues/88727 +fn matches() -> bool { + (match () { _ => true }) && match () { _ => true }; //~ ERROR mismatched types + (match () { _ => true }) && match () { _ => true }; //~ ERROR mismatched types + //~^ ERROR expected `;`, found keyword `match` + (match () { _ => true }) && true; //~ ERROR mismatched types + ((match () { _ => true })) && true //~ ERROR mismatched types + //~^ ERROR mismatched types +} fn main() {} diff --git a/tests/ui/parser/expr-as-stmt.rs b/tests/ui/parser/expr-as-stmt.rs index 99c85e65baa55..94917432cb03a 100644 --- a/tests/ui/parser/expr-as-stmt.rs +++ b/tests/ui/parser/expr-as-stmt.rs @@ -76,4 +76,13 @@ fn r#unsafe() -> i32 { //~^ ERROR mismatched types } +// https://github.com/rust-lang/rust/issues/88727 +fn matches() -> bool { + match () { _ => true } && match () { _ => true }; //~ ERROR mismatched types + match () { _ => true } && match () { _ => true } //~ ERROR mismatched types + //~^ ERROR expected `;`, found keyword `match` + match () { _ => true } && true; //~ ERROR mismatched types + match () { _ => true } && true //~ ERROR mismatched types + //~^ ERROR mismatched types +} fn main() {} diff --git a/tests/ui/parser/expr-as-stmt.stderr b/tests/ui/parser/expr-as-stmt.stderr index 562162ef3946d..4681129babab0 100644 --- a/tests/ui/parser/expr-as-stmt.stderr +++ b/tests/ui/parser/expr-as-stmt.stderr @@ -77,6 +77,15 @@ help: parentheses are required to parse this as an expression LL | (unsafe { 1 }) + unsafe { 1 } | + + +error: expected `;`, found keyword `match` + --> $DIR/expr-as-stmt.rs:82:53 + | +LL | match () { _ => true } && match () { _ => true } + | ^ help: add `;` here +LL | +LL | match () { _ => true } && true; + | ----- unexpected token + error[E0308]: mismatched types --> $DIR/expr-as-stmt.rs:64:7 | @@ -229,11 +238,7 @@ error[E0308]: mismatched types LL | match () { () => 1 } + match () { () => 1 } | ^^^^^^^^^^^^^^^^^^^^ expected `()`, found integer | -help: consider using a semicolon here - | -LL | match () { () => 1 }; + match () { () => 1 } - | + -help: alternatively, parentheses are required to parse this as an expression +help: parentheses are required to parse this as an expression | LL | (match () { () => 1 }) + match () { () => 1 } | + + @@ -249,7 +254,65 @@ help: you might have meant to return this value LL | unsafe { return 1; } + unsafe { 1 } | ++++++ + -error: aborting due to 22 previous errors +error[E0308]: mismatched types + --> $DIR/expr-as-stmt.rs:81:5 + | +LL | match () { _ => true } && match () { _ => true }; + | ^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found `bool` + | +help: parentheses are required to parse this as an expression + | +LL | (match () { _ => true }) && match () { _ => true }; + | + + + +error[E0308]: mismatched types + --> $DIR/expr-as-stmt.rs:82:5 + | +LL | match () { _ => true } && match () { _ => true } + | ^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found `bool` + | +help: parentheses are required to parse this as an expression + | +LL | (match () { _ => true }) && match () { _ => true } + | + + + +error[E0308]: mismatched types + --> $DIR/expr-as-stmt.rs:84:5 + | +LL | match () { _ => true } && true; + | ^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found `bool` + | +help: parentheses are required to parse this as an expression + | +LL | (match () { _ => true }) && true; + | + + + +error[E0308]: mismatched types + --> $DIR/expr-as-stmt.rs:85:5 + | +LL | match () { _ => true } && true + | ^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found `bool` + | +help: parentheses are required to parse this as an expression + | +LL | (match () { _ => true }) && true + | + + + +error[E0308]: mismatched types + --> $DIR/expr-as-stmt.rs:85:28 + | +LL | fn matches() -> bool { + | ---- expected `bool` because of return type +... +LL | match () { _ => true } && true + | ^^^^^^^ expected `bool`, found `&&bool` + | +help: parentheses are required to parse this as an expression + | +LL | (match () { _ => true }) && true + | + + + +error: aborting due to 28 previous errors Some errors have detailed explanations: E0308, E0600, E0614. For more information about an error, try `rustc --explain E0308`. diff --git a/tests/ui/suggestions/match-needing-semi.stderr b/tests/ui/suggestions/match-needing-semi.stderr index 8f74997fdbee0..b5f01d7038c0d 100644 --- a/tests/ui/suggestions/match-needing-semi.stderr +++ b/tests/ui/suggestions/match-needing-semi.stderr @@ -28,20 +28,9 @@ LL | | 4 => 1, LL | | 3 => 2, LL | | _ => 2 LL | | } - | |_____^ expected `()`, found integer - | -help: consider using a semicolon here - | -LL | }; - | + -help: alternatively, parentheses are required to parse this as an expression - | -LL ~ (match 3 { -LL | 4 => 1, -LL | 3 => 2, -LL | _ => 2 -LL ~ }) - | + | | ^- help: consider using a semicolon here + | |_____| + | expected `()`, found integer error: aborting due to 2 previous errors From ff60e5c3f3a00fcf03fc4d50432cd76f2a890a9f Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Esteban=20K=C3=BCber?= Date: Tue, 2 Sep 2025 00:02:16 +0000 Subject: [PATCH 3/3] Suggest parentheses around if-expressions ``` error[E0308]: mismatched types --> $DIR/expr-as-stmt-2.rs:15:15 | LL | if true { true } else { false } && true; | ----------^^^^----------------- | | | | | expected `()`, found `bool` | expected this to be `()` | help: parentheses are required to parse this as an expression | LL | (if true { true } else { false }) && true; | + + ``` --- compiler/rustc_hir_typeck/src/coercion.rs | 2 +- .../rustc_hir_typeck/src/fn_ctxt/checks.rs | 50 ++---- .../src/fn_ctxt/suggestions.rs | 146 +++++++++++----- tests/ui/parser/expr-as-stmt-2.rs | 23 ++- tests/ui/parser/expr-as-stmt-2.stderr | 156 +++++++++++++++++- 5 files changed, 301 insertions(+), 76 deletions(-) diff --git a/compiler/rustc_hir_typeck/src/coercion.rs b/compiler/rustc_hir_typeck/src/coercion.rs index e66601631fcc8..b99f811db1a14 100644 --- a/compiler/rustc_hir_typeck/src/coercion.rs +++ b/compiler/rustc_hir_typeck/src/coercion.rs @@ -1897,7 +1897,7 @@ impl<'tcx, 'exprs, E: AsCoercionSite> CoerceMany<'tcx, 'exprs, E> { fcx.suggest_semicolon_at_end(cond_expr.span, &mut err); } } - }; + } // If this is due to an explicit `return`, suggest adding a return type. if let Some((fn_id, fn_decl)) = fcx.get_fn_decl(block_or_return_id) diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs index 33dc56d49b499..94b635c41b4b2 100644 --- a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs +++ b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs @@ -1912,39 +1912,23 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { hir::StmtKind::Expr(ref expr) => { // Check with expected type of `()`. self.check_expr_has_type_or_error(expr, self.tcx.types.unit, |err| { - if expr.can_have_side_effects() { - let hir_id = stmt.hir_id; - if let hir::ExprKind::Match(..) = expr.kind - && let hir::Node::Block(b) = self.tcx.parent_hir_node(hir_id) - && let mut stmts = b.stmts.iter().skip_while(|s| s.hir_id != hir_id) - && let Some(_) = stmts.next() // The statement from the `match` - && let Some(next) = match (stmts.next(), b.expr) { - (Some(next), _) => match next.kind { - hir::StmtKind::Expr(next) | hir::StmtKind::Semi(next) => Some(next), - _ => None, - }, - (None, Some(next)) => Some(next), - _ => None, - } - && let hir::ExprKind::AddrOf(..) - | hir::ExprKind::Unary(..) - | hir::ExprKind::Err(_) = next.kind - { - // We have something like `match () { _ => true } && true`. Suggest - // wrapping in parentheses. We find the statement or expression - // following the `match` (`&& true`) and see if it is something that - // can reasonably be interpreted as a binop following an expression. - err.multipart_suggestion( - "parentheses are required to parse this as an expression", - vec![ - (expr.span.shrink_to_lo(), "(".to_string()), - (expr.span.shrink_to_hi(), ")".to_string()), - ], - Applicability::MachineApplicable, - ); - } else { - self.suggest_semicolon_at_end(expr.span, err); - } + if self.is_next_stmt_expr_continuation(stmt.hir_id) + && let hir::ExprKind::Match(..) | hir::ExprKind::If(..) = expr.kind + { + // We have something like `match () { _ => true } && true`. Suggest + // wrapping in parentheses. We find the statement or expression + // following the `match` (`&& true`) and see if it is something that + // can reasonably be interpreted as a binop following an expression. + err.multipart_suggestion( + "parentheses are required to parse this as an expression", + vec![ + (expr.span.shrink_to_lo(), "(".to_string()), + (expr.span.shrink_to_hi(), ")".to_string()), + ], + Applicability::MachineApplicable, + ); + } else if expr.can_have_side_effects() { + self.suggest_semicolon_at_end(expr.span, err); } }); } diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs index aca3840712e79..84ea2ec0f8a43 100644 --- a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs +++ b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs @@ -1,3 +1,4 @@ +// ignore-tidy-filelength use core::cmp::min; use core::iter; @@ -766,56 +767,121 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { needs_block: bool, parent_is_closure: bool, ) { - if expected.is_unit() { - // `BlockTailExpression` only relevant if the tail expr would be - // useful on its own. - match expression.kind { - ExprKind::Call(..) - | ExprKind::MethodCall(..) - | ExprKind::Loop(..) - | ExprKind::If(..) - | ExprKind::Match(..) - | ExprKind::Block(..) - if expression.can_have_side_effects() - // If the expression is from an external macro, then do not suggest - // adding a semicolon, because there's nowhere to put it. - // See issue #81943. - && !expression.span.in_external_macro(self.tcx.sess.source_map()) => + if !expected.is_unit() { + return; + } + // `BlockTailExpression` only relevant if the tail expr would be + // useful on its own. + match expression.kind { + ExprKind::Call(..) + | ExprKind::MethodCall(..) + | ExprKind::Loop(..) + | ExprKind::If(..) + | ExprKind::Match(..) + | ExprKind::Block(..) + if expression.can_have_side_effects() + // If the expression is from an external macro, then do not suggest + // adding a semicolon, because there's nowhere to put it. + // See issue #81943. + && !expression.span.in_external_macro(self.tcx.sess.source_map()) => + { + if needs_block { + err.multipart_suggestion( + "consider using a semicolon here", + vec![ + (expression.span.shrink_to_lo(), "{ ".to_owned()), + (expression.span.shrink_to_hi(), "; }".to_owned()), + ], + Applicability::MachineApplicable, + ); + } else if let hir::Node::Block(block) = self.tcx.parent_hir_node(expression.hir_id) + && let hir::Node::Expr(expr) = self.tcx.parent_hir_node(block.hir_id) + && let hir::Node::Expr(if_expr) = self.tcx.parent_hir_node(expr.hir_id) + && let hir::ExprKind::If(_cond, _then, Some(_else)) = if_expr.kind + && let hir::Node::Stmt(stmt) = self.tcx.parent_hir_node(if_expr.hir_id) + && let hir::StmtKind::Expr(_) = stmt.kind + && self.is_next_stmt_expr_continuation(stmt.hir_id) { - if needs_block { - err.multipart_suggestion( - "consider using a semicolon here", - vec![ - (expression.span.shrink_to_lo(), "{ ".to_owned()), - (expression.span.shrink_to_hi(), "; }".to_owned()), - ], - Applicability::MachineApplicable, - ); - } else { - err.span_suggestion( - expression.span.shrink_to_hi(), - "consider using a semicolon here", - ";", - Applicability::MachineApplicable, - ); - } + err.multipart_suggestion( + "parentheses are required to parse this as an expression", + vec![ + (stmt.span.shrink_to_lo(), "(".to_string()), + (stmt.span.shrink_to_hi(), ")".to_string()), + ], + Applicability::MachineApplicable, + ); + } else { + err.span_suggestion( + expression.span.shrink_to_hi(), + "consider using a semicolon here", + ";", + Applicability::MachineApplicable, + ); } - ExprKind::Path(..) | ExprKind::Lit(_) - if parent_is_closure - && !expression.span.in_external_macro(self.tcx.sess.source_map()) => + } + ExprKind::Path(..) | ExprKind::Lit(_) + if parent_is_closure + && !expression.span.in_external_macro(self.tcx.sess.source_map()) => + { + err.span_suggestion_verbose( + expression.span.shrink_to_lo(), + "consider ignoring the value", + "_ = ", + Applicability::MachineApplicable, + ); + } + _ => { + if let hir::Node::Block(block) = self.tcx.parent_hir_node(expression.hir_id) + && let hir::Node::Expr(expr) = self.tcx.parent_hir_node(block.hir_id) + && let hir::Node::Expr(if_expr) = self.tcx.parent_hir_node(expr.hir_id) + && let hir::ExprKind::If(_cond, _then, Some(_else)) = if_expr.kind + && let hir::Node::Stmt(stmt) = self.tcx.parent_hir_node(if_expr.hir_id) + && let hir::StmtKind::Expr(_) = stmt.kind + && self.is_next_stmt_expr_continuation(stmt.hir_id) { - err.span_suggestion_verbose( - expression.span.shrink_to_lo(), - "consider ignoring the value", - "_ = ", + // The error is pointing at an arm of an if-expression, and we want to get the + // `Span` of the whole if-expression for the suggestion. This only works for a + // single level of nesting, which is fine. + // We have something like `if true { false } else { true } && true`. Suggest + // wrapping in parentheses. We find the statement or expression following the + // `if` (`&& true`) and see if it is something that can reasonably be + // interpreted as a binop following an expression. + err.multipart_suggestion( + "parentheses are required to parse this as an expression", + vec![ + (stmt.span.shrink_to_lo(), "(".to_string()), + (stmt.span.shrink_to_hi(), ")".to_string()), + ], Applicability::MachineApplicable, ); } - _ => (), } } } + pub(crate) fn is_next_stmt_expr_continuation(&self, hir_id: HirId) -> bool { + if let hir::Node::Block(b) = self.tcx.parent_hir_node(hir_id) + && let mut stmts = b.stmts.iter().skip_while(|s| s.hir_id != hir_id) + && let Some(_) = stmts.next() // The statement the statement that was passed in + && let Some(next) = match (stmts.next(), b.expr) { // The following statement + (Some(next), _) => match next.kind { + hir::StmtKind::Expr(next) | hir::StmtKind::Semi(next) => Some(next), + _ => None, + }, + (None, Some(next)) => Some(next), + _ => None, + } + && let hir::ExprKind::AddrOf(..) // prev_stmt && next + | hir::ExprKind::Unary(..) // prev_stmt * next + | hir::ExprKind::Err(_) = next.kind + // prev_stmt + next + { + true + } else { + false + } + } + /// A possible error is to forget to add a return type that is needed: /// /// ```compile_fail,E0308 diff --git a/tests/ui/parser/expr-as-stmt-2.rs b/tests/ui/parser/expr-as-stmt-2.rs index 3a18bdc3b730a..4b1f62d8056df 100644 --- a/tests/ui/parser/expr-as-stmt-2.rs +++ b/tests/ui/parser/expr-as-stmt-2.rs @@ -7,4 +7,25 @@ fn foo(a: Option, b: Option) -> bool { if let Some(y) = a { true } else { false } } -fn main() {} +fn bar() -> bool { + false +} + +fn main() { + if true { true } else { false } && true; + //~^ ERROR mismatched types + //~| ERROR mismatched types + if true { true } else { false } && if true { true } else { false }; + //~^ ERROR mismatched types + //~| ERROR mismatched types + if true { true } else { false } if true { true } else { false }; + //~^ ERROR mismatched types + //~| ERROR mismatched types + if true { bar() } else { bar() } && if true { bar() } else { bar() }; + //~^ ERROR mismatched types + //~| ERROR mismatched types + if true { bar() } else { bar() } if true { bar() } else { bar() }; + //~^ ERROR mismatched types + //~| ERROR mismatched types + let _ = if true { true } else { false } && true; // ok +} diff --git a/tests/ui/parser/expr-as-stmt-2.stderr b/tests/ui/parser/expr-as-stmt-2.stderr index 2b6314c38ceb6..f9838ee0299cf 100644 --- a/tests/ui/parser/expr-as-stmt-2.stderr +++ b/tests/ui/parser/expr-as-stmt-2.stderr @@ -7,6 +7,10 @@ LL | if let Some(x) = a { true } else { false } | | expected `()`, found `bool` | expected this to be `()` | +help: parentheses are required to parse this as an expression + | +LL | (if let Some(x) = a { true } else { false }) + | + + help: you might have meant to return this value | LL | if let Some(x) = a { return true; } else { false } @@ -21,6 +25,10 @@ LL | if let Some(x) = a { true } else { false } | | expected `()`, found `bool` | expected this to be `()` | +help: parentheses are required to parse this as an expression + | +LL | (if let Some(x) = a { true } else { false }) + | + + help: you might have meant to return this value | LL | if let Some(x) = a { true } else { return false; } @@ -41,6 +49,152 @@ help: parentheses are required to parse this as an expression LL | (if let Some(x) = a { true } else { false }) | + + -error: aborting due to 3 previous errors +error[E0308]: mismatched types + --> $DIR/expr-as-stmt-2.rs:15:15 + | +LL | if true { true } else { false } && true; + | ----------^^^^----------------- + | | | + | | expected `()`, found `bool` + | expected this to be `()` + | +help: parentheses are required to parse this as an expression + | +LL | (if true { true } else { false }) && true; + | + + + +error[E0308]: mismatched types + --> $DIR/expr-as-stmt-2.rs:15:29 + | +LL | if true { true } else { false } && true; + | ------------------------^^^^^-- + | | | + | | expected `()`, found `bool` + | expected this to be `()` + | +help: parentheses are required to parse this as an expression + | +LL | (if true { true } else { false }) && true; + | + + + +error[E0308]: mismatched types + --> $DIR/expr-as-stmt-2.rs:18:15 + | +LL | if true { true } else { false } && if true { true } else { false }; + | ----------^^^^----------------- + | | | + | | expected `()`, found `bool` + | expected this to be `()` + | +help: parentheses are required to parse this as an expression + | +LL | (if true { true } else { false }) && if true { true } else { false }; + | + + + +error[E0308]: mismatched types + --> $DIR/expr-as-stmt-2.rs:18:29 + | +LL | if true { true } else { false } && if true { true } else { false }; + | ------------------------^^^^^-- + | | | + | | expected `()`, found `bool` + | expected this to be `()` + | +help: parentheses are required to parse this as an expression + | +LL | (if true { true } else { false }) && if true { true } else { false }; + | + + + +error[E0308]: mismatched types + --> $DIR/expr-as-stmt-2.rs:21:15 + | +LL | if true { true } else { false } if true { true } else { false }; + | ----------^^^^----------------- + | | | + | | expected `()`, found `bool` + | expected this to be `()` + +error[E0308]: mismatched types + --> $DIR/expr-as-stmt-2.rs:21:29 + | +LL | if true { true } else { false } if true { true } else { false }; + | ------------------------^^^^^-- + | | | + | | expected `()`, found `bool` + | expected this to be `()` + +error[E0308]: mismatched types + --> $DIR/expr-as-stmt-2.rs:24:15 + | +LL | if true { bar() } else { bar() } && if true { bar() } else { bar() }; + | ----------^^^^^----------------- + | | | + | | expected `()`, found `bool` + | expected this to be `()` + | +help: parentheses are required to parse this as an expression + | +LL | (if true { bar() } else { bar() }) && if true { bar() } else { bar() }; + | + + +help: consider using a semicolon here + | +LL | if true { bar() } else { bar() }; && if true { bar() } else { bar() }; + | + + +error[E0308]: mismatched types + --> $DIR/expr-as-stmt-2.rs:24:30 + | +LL | if true { bar() } else { bar() } && if true { bar() } else { bar() }; + | -------------------------^^^^^-- + | | | + | | expected `()`, found `bool` + | expected this to be `()` + | +help: parentheses are required to parse this as an expression + | +LL | (if true { bar() } else { bar() }) && if true { bar() } else { bar() }; + | + + +help: consider using a semicolon here + | +LL | if true { bar() } else { bar() }; && if true { bar() } else { bar() }; + | + + +error[E0308]: mismatched types + --> $DIR/expr-as-stmt-2.rs:27:15 + | +LL | if true { bar() } else { bar() } if true { bar() } else { bar() }; + | ----------^^^^^----------------- + | | | + | | expected `()`, found `bool` + | expected this to be `()` + | +help: consider using a semicolon here + | +LL | if true { bar(); } else { bar() } if true { bar() } else { bar() }; + | + +help: consider using a semicolon here + | +LL | if true { bar() } else { bar() }; if true { bar() } else { bar() }; + | + + +error[E0308]: mismatched types + --> $DIR/expr-as-stmt-2.rs:27:30 + | +LL | if true { bar() } else { bar() } if true { bar() } else { bar() }; + | -------------------------^^^^^-- + | | | + | | expected `()`, found `bool` + | expected this to be `()` + | +help: consider using a semicolon here + | +LL | if true { bar() } else { bar(); } if true { bar() } else { bar() }; + | + +help: consider using a semicolon here + | +LL | if true { bar() } else { bar() }; if true { bar() } else { bar() }; + | + + +error: aborting due to 13 previous errors For more information about this error, try `rustc --explain E0308`.