diff --git a/compiler/rustc_hir_typeck/src/_if.rs b/compiler/rustc_hir_typeck/src/_if.rs new file mode 100644 index 0000000000000..3a76041ec72f9 --- /dev/null +++ b/compiler/rustc_hir_typeck/src/_if.rs @@ -0,0 +1,232 @@ +use rustc_hir as hir; +use rustc_hir::{ExprKind, HirId}; +use rustc_infer::traits::{IfChainCoerceCause, ObligationCauseCode}; +use rustc_middle::bug; +use rustc_middle::ty::{Ty, TypeVisitableExt}; +use rustc_span::Span; +use rustc_span::def_id::LocalDefId; + +use crate::Expectation; +use crate::coercion::CoerceMany; +use crate::diverges::Diverges; +use crate::fn_ctxt::FnCtxt; + +/// State shared across all branches of an `else if` chain check. +struct ElseIfChainCx<'a, 'tcx> { + coerce: &'a mut CoerceMany<'tcx>, + outer_if_expr_id: HirId, + orig_expected: Expectation<'tcx>, + tail_defines_return_position_impl_trait: Option, +} + +#[derive(Copy, Clone)] +struct PrevBranch<'tcx> { + hir_id: HirId, + ty: Ty<'tcx>, +} + +fn chain_has_terminal_else_block(expr: &hir::Expr<'_>) -> bool { + let mut cur = expr; + loop { + match cur.kind { + ExprKind::If(_, _, Some(next)) => cur = next, + ExprKind::If(_, _, None) => return false, + _ => return true, + } + } +} + +fn has_empty_block_chains(expr: &hir::Expr<'_>) -> bool { + let mut cur = expr; + loop { + match cur.kind { + ExprKind::If(_, then, opt_else) => { + let ExprKind::Block(then_block, _) = then.kind else { + return true; + }; + if then_block.expr.is_none() { + return true; + } + match opt_else { + Some(next) => cur = next, + None => return false, + } + } + ExprKind::Block(block, _) => return block.expr.is_none(), + _ => return false, + } + } +} + +impl<'a, 'tcx> FnCtxt<'a, 'tcx> { + // A generic function for checking the 'then' and 'else' clauses in an 'if' + // or 'if-else' expression. + pub(crate) fn check_expr_if( + &self, + expr_id: HirId, + cond_expr: &'tcx hir::Expr<'tcx>, + then_expr: &'tcx hir::Expr<'tcx>, + opt_else_expr: Option<&'tcx hir::Expr<'tcx>>, + sp: Span, + orig_expected: Expectation<'tcx>, + ) -> Ty<'tcx> { + let cond_ty = self.check_expr_has_type_or_error(cond_expr, self.tcx.types.bool, |_| {}); + + let (expected, then_ty, cond_diverges, then_diverges) = + self.check_current_if_branch(cond_expr, then_expr, orig_expected); + + // We've already taken the expected type's preferences + // into account when typing the `then` branch. To figure + // out the initial shot at a LUB, we thus only consider + // `expected` if it represents a *hard* constraint + // (`only_has_type`); otherwise, we just go with a + // fresh type variable. + let coerce_to_ty = expected.coercion_target_type(self, sp); + let mut coerce = CoerceMany::with_capacity(coerce_to_ty, 2); + + coerce.coerce(self, &self.misc(sp), then_expr, then_ty); + + if let Some(else_expr) = opt_else_expr { + let else_diverges = if chain_has_terminal_else_block(else_expr) + && let ExprKind::If(..) = else_expr.kind + // Chains containing `{}` arms go to the path below. + // Otherwise for code like + // let x = if c1 { &() } else if c2 {} else {}; + // the "consider borrowing here" suggestion comes out as + // } else if c2 &{ + // which isn't valid syntax. Having an empty block in an if chain is an edge + // case in real code, so the fallback is harmless. + && !has_empty_block_chains(else_expr) + { + let mut cx = ElseIfChainCx { + coerce: &mut coerce, + outer_if_expr_id: expr_id, + orig_expected, + tail_defines_return_position_impl_trait: self + .return_position_impl_trait_from_match_expectation(orig_expected), + }; + self.check_expr_with_check_fn(else_expr, expected, |this| { + this.check_else_if_branch( + &mut cx, + PrevBranch { hir_id: then_expr.hir_id, ty: then_ty }, + else_expr, + ) + }); + self.diverges.get() + } else { + let else_ty = self.check_expr_with_expectation(else_expr, expected); + let else_diverges = self.diverges.get(); + let if_cause = self.if_cause( + expr_id, + else_expr, + self.return_position_impl_trait_from_match_expectation(orig_expected), + ); + coerce.coerce(self, &if_cause, else_expr, else_ty); + else_diverges + }; + + // We won't diverge unless both branches do (or the condition does). + self.diverges.set(cond_diverges | then_diverges & else_diverges); + } else { + self.if_fallback_coercion(sp, cond_expr, then_expr, &mut coerce); + + // If the condition is false we can't diverge. + self.diverges.set(cond_diverges); + } + + let result_ty = coerce.complete(self); + if let Err(guar) = cond_ty.error_reported() { + Ty::new_error(self.tcx, guar) + } else { + result_ty + } + } + + fn check_current_if_branch( + &self, + cond_expr: &'tcx hir::Expr<'tcx>, + then_expr: &'tcx hir::Expr<'tcx>, + orig_expected: Expectation<'tcx>, + ) -> (Expectation<'tcx>, Ty<'tcx>, Diverges, Diverges) { + self.warn_if_unreachable( + cond_expr.hir_id, + then_expr.span, + "block in `if` or `while` expression", + ); + + let cond_diverges = self.diverges.get(); + self.diverges.set(Diverges::Maybe); + + let expected = orig_expected.try_structurally_resolve_and_adjust_for_branches(self); + let then_ty = self.check_expr_with_expectation(then_expr, expected); + let then_diverges = self.diverges.get(); + self.diverges.set(Diverges::Maybe); + + (expected, then_ty, cond_diverges, then_diverges) + } + + fn check_else_if_branch( + &self, + cx: &mut ElseIfChainCx<'_, 'tcx>, + prev_branch: PrevBranch<'tcx>, + current_expr: &'tcx hir::Expr<'tcx>, + ) -> Ty<'tcx> { + let ExprKind::If(cond_expr, then_expr, opt_else_expr) = current_expr.kind else { + bug!("check_else_if_branch called on non-`if` expr"); + }; + self.check_expr_has_type_or_error(cond_expr, self.tcx.types.bool, |_| {}); + + let (expected, then_ty, cond_diverges, then_diverges) = + self.check_current_if_branch(cond_expr, then_expr, cx.orig_expected); + + self.coerce_branch_against_prev(cx, prev_branch, then_expr, then_ty); + + let next_prev = PrevBranch { hir_id: then_expr.hir_id, ty: then_ty }; + + let else_diverges = match opt_else_expr { + Some(else_expr) if let ExprKind::If(..) = else_expr.kind => { + self.check_expr_with_check_fn(else_expr, expected, |this| { + this.check_else_if_branch(cx, next_prev, else_expr) + }); + self.diverges.get() + } + Some(else_expr) => { + let else_ty = self.check_expr_with_expectation(else_expr, expected); + let else_diverges = self.diverges.get(); + self.coerce_branch_against_prev(cx, next_prev, else_expr, else_ty); + else_diverges + } + None => bug!("chain entered without a final else; broken `has_final_else_arm`"), + }; + + // We won't diverge unless cond does, or both then and else do. + self.diverges.set(cond_diverges | then_diverges & else_diverges); + + cx.coerce.merged_ty() + } + + fn coerce_branch_against_prev( + &self, + cx: &mut ElseIfChainCx<'_, 'tcx>, + prev: PrevBranch<'tcx>, + current_branch_expr: &'tcx hir::Expr<'tcx>, + current_branch_ty: Ty<'tcx>, + ) { + let prev_branch_span = self.find_block_span_from_hir_id(prev.hir_id); + let branch_span = self.find_block_span_from_hir_id(current_branch_expr.hir_id); + let cause = self.cause( + branch_span, + ObligationCauseCode::IfChainCoerce(Box::new(IfChainCoerceCause { + outer_if_expr_id: cx.outer_if_expr_id, + source_branch_expr_id: prev.hir_id, + source_branch_ty: prev.ty, + source_branch_span: prev_branch_span, + target_branch_expr_id: current_branch_expr.hir_id, + target_branch_ty: current_branch_ty, + target_branch_span: branch_span, + tail_defines_return_position_impl_trait: cx.tail_defines_return_position_impl_trait, + })), + ); + cx.coerce.coerce(self, &cause, current_branch_expr, current_branch_ty); + } +} diff --git a/compiler/rustc_hir_typeck/src/coercion.rs b/compiler/rustc_hir_typeck/src/coercion.rs index abd5f38f0ed08..817049a41b205 100644 --- a/compiler/rustc_hir_typeck/src/coercion.rs +++ b/compiler/rustc_hir_typeck/src/coercion.rs @@ -46,7 +46,8 @@ use rustc_hir_analysis::hir_ty_lowering::HirTyLowerer; use rustc_infer::infer::relate::RelateResult; use rustc_infer::infer::{DefineOpaqueTypes, InferOk, InferResult, RegionVariableOrigin}; use rustc_infer::traits::{ - MatchExpressionArmCause, Obligation, PredicateObligation, PredicateObligations, SelectionError, + IfChainCoerceCause, MatchExpressionArmCause, Obligation, PredicateObligation, + PredicateObligations, SelectionError, }; use rustc_middle::span_bug; use rustc_middle::ty::adjustment::{ @@ -1769,6 +1770,38 @@ impl<'tcx> CoerceMany<'tcx> { ); } } + ObligationCauseCode::IfChainCoerce(box IfChainCoerceCause { + source_branch_expr_id: prev_branch_expr_id, + source_branch_ty: prev_branch_ty, + source_branch_span: prev_branch_span, + target_branch_expr_id: branch_expr_id, + target_branch_ty: branch_ty, + target_branch_span: branch_span, + tail_defines_return_position_impl_trait: Some(rpit_def_id), + .. + }) => { + err = fcx.err_ctxt().report_mismatched_types( + cause, + fcx.param_env, + expected, + found, + coercion_error, + ); + let prev_expr_span = + fcx.tcx.hir_node(prev_branch_expr_id).expect_expr().span; + let branch_expr_span = fcx.tcx.hir_node(branch_expr_id).expect_expr().span; + // Don't suggest wrapping whole block in `Box::new`. + if prev_branch_span != prev_expr_span && branch_span != branch_expr_span { + self.suggest_boxing_tail_for_return_position_impl_trait( + fcx, + &mut err, + rpit_def_id, + prev_branch_ty, + branch_ty, + [prev_branch_span, branch_span].into_iter(), + ); + } + } _ => { err = fcx.err_ctxt().report_mismatched_types( cause, diff --git a/compiler/rustc_hir_typeck/src/expr.rs b/compiler/rustc_hir_typeck/src/expr.rs index fd9c1bc8780ee..7a9bda10a64f8 100644 --- a/compiler/rustc_hir_typeck/src/expr.rs +++ b/compiler/rustc_hir_typeck/src/expr.rs @@ -201,27 +201,17 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { self.check_expr_with_expectation_and_needs(expr, NoExpectation, needs) } - /// Check an expr with an expectation type which may be used to eagerly - /// guide inference when evaluating that expr. - #[instrument(skip(self, expr), level = "debug")] - pub(super) fn check_expr_with_expectation( - &self, - expr: &'tcx hir::Expr<'tcx>, - expected: Expectation<'tcx>, - ) -> Ty<'tcx> { - self.check_expr_with_expectation_and_args(expr, expected, None) - } - - /// Same as [`Self::check_expr_with_expectation`], but allows us to pass in - /// the arguments of a [`ExprKind::Call`] when evaluating its callee that - /// is an [`ExprKind::Path`]. We use this to refine the spans for certain - /// well-formedness guarantees for the path expr. - pub(super) fn check_expr_with_expectation_and_args( + /// Run the per-expression framing (`write_ty`, divergence handling, + /// unreachable warnings) around `check`. + pub(super) fn check_expr_with_check_fn( &self, expr: &'tcx hir::Expr<'tcx>, expected: Expectation<'tcx>, - call_expr_and_args: Option<(&'tcx hir::Expr<'tcx>, &'tcx [hir::Expr<'tcx>])>, - ) -> Ty<'tcx> { + check: F, + ) -> Ty<'tcx> + where + F: FnOnce(&Self) -> Ty<'tcx>, + { if self.tcx().sess.verbose_internals() { // make this code only run with -Zverbose-internals because it is probably slow if let Ok(lint_str) = self.tcx.sess.source_map().span_to_snippet(expr.span) { @@ -264,13 +254,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { self.diverges.set(self.function_diverges_because_of_empty_arguments.get()) }; - let ty = ensure_sufficient_stack(|| match &expr.kind { - // Intercept the callee path expr and give it better spans. - hir::ExprKind::Path( - qpath @ (hir::QPath::Resolved(..) | hir::QPath::TypeRelative(..)), - ) => self.check_expr_path(qpath, expr, call_expr_and_args), - _ => self.check_expr_kind(expr, expected), - }); + let ty = ensure_sufficient_stack(|| check(self)); let ty = self.resolve_vars_if_possible(ty); // Warn for non-block expressions with diverging children. @@ -320,6 +304,36 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { ty } + /// Check an expr with an expectation type which may be used to eagerly + /// guide inference when evaluating that expr. + #[instrument(skip(self, expr), level = "debug")] + pub(super) fn check_expr_with_expectation( + &self, + expr: &'tcx hir::Expr<'tcx>, + expected: Expectation<'tcx>, + ) -> Ty<'tcx> { + self.check_expr_with_expectation_and_args(expr, expected, None) + } + + /// Same as [`Self::check_expr_with_expectation`], but allows us to pass in + /// the arguments of a [`ExprKind::Call`] when evaluating its callee that + /// is an [`ExprKind::Path`]. We use this to refine the spans for certain + /// well-formedness guarantees for the path expr. + pub(super) fn check_expr_with_expectation_and_args( + &self, + expr: &'tcx hir::Expr<'tcx>, + expected: Expectation<'tcx>, + call_expr_and_args: Option<(&'tcx hir::Expr<'tcx>, &'tcx [hir::Expr<'tcx>])>, + ) -> Ty<'tcx> { + self.check_expr_with_check_fn(expr, expected, |this| match &expr.kind { + // Intercept the callee path expr and give it better spans. + hir::ExprKind::Path( + qpath @ (hir::QPath::Resolved(..) | hir::QPath::TypeRelative(..)), + ) => this.check_expr_path(qpath, expr, call_expr_and_args), + _ => this.check_expr_kind(expr, expected), + }) + } + #[instrument(skip(self, expr), level = "debug")] fn check_expr_kind( &self, @@ -1165,72 +1179,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { } } - // A generic function for checking the 'then' and 'else' clauses in an 'if' - // or 'if-else' expression. - fn check_expr_if( - &self, - expr_id: HirId, - cond_expr: &'tcx hir::Expr<'tcx>, - then_expr: &'tcx hir::Expr<'tcx>, - opt_else_expr: Option<&'tcx hir::Expr<'tcx>>, - sp: Span, - orig_expected: Expectation<'tcx>, - ) -> Ty<'tcx> { - let cond_ty = self.check_expr_has_type_or_error(cond_expr, self.tcx.types.bool, |_| {}); - - self.warn_if_unreachable( - cond_expr.hir_id, - then_expr.span, - "block in `if` or `while` expression", - ); - - let cond_diverges = self.diverges.get(); - self.diverges.set(Diverges::Maybe); - - let expected = orig_expected.try_structurally_resolve_and_adjust_for_branches(self); - let then_ty = self.check_expr_with_expectation(then_expr, expected); - let then_diverges = self.diverges.get(); - self.diverges.set(Diverges::Maybe); - - // We've already taken the expected type's preferences - // into account when typing the `then` branch. To figure - // out the initial shot at a LUB, we thus only consider - // `expected` if it represents a *hard* constraint - // (`only_has_type`); otherwise, we just go with a - // fresh type variable. - let coerce_to_ty = expected.coercion_target_type(self, sp); - let mut coerce = CoerceMany::with_capacity(coerce_to_ty, 2); - - coerce.coerce(self, &self.misc(sp), then_expr, then_ty); - - if let Some(else_expr) = opt_else_expr { - let else_ty = self.check_expr_with_expectation(else_expr, expected); - let else_diverges = self.diverges.get(); - - let tail_defines_return_position_impl_trait = - self.return_position_impl_trait_from_match_expectation(orig_expected); - let if_cause = - self.if_cause(expr_id, else_expr, tail_defines_return_position_impl_trait); - - coerce.coerce(self, &if_cause, else_expr, else_ty); - - // We won't diverge unless both branches do (or the condition does). - self.diverges.set(cond_diverges | then_diverges & else_diverges); - } else { - self.if_fallback_coercion(sp, cond_expr, then_expr, &mut coerce); - - // If the condition is false we can't diverge. - self.diverges.set(cond_diverges); - } - - let result_ty = coerce.complete(self); - if let Err(guar) = cond_ty.error_reported() { - Ty::new_error(self.tcx, guar) - } else { - result_ty - } - } - /// Type check assignment expression `expr` of form `lhs = rhs`. /// The expected type is `()` and is passed to the function for the purposes of diagnostics. fn check_expr_assign( diff --git a/compiler/rustc_hir_typeck/src/lib.rs b/compiler/rustc_hir_typeck/src/lib.rs index 15729bc311e57..e7b3a24e2de9a 100644 --- a/compiler/rustc_hir_typeck/src/lib.rs +++ b/compiler/rustc_hir_typeck/src/lib.rs @@ -6,6 +6,7 @@ #![feature(trim_prefix_suffix)] // tidy-alphabetical-end +mod _if; mod _match; mod autoderef; mod callee; diff --git a/compiler/rustc_middle/src/traits/mod.rs b/compiler/rustc_middle/src/traits/mod.rs index daa0df4013272..2db99df4458f5 100644 --- a/compiler/rustc_middle/src/traits/mod.rs +++ b/compiler/rustc_middle/src/traits/mod.rs @@ -339,6 +339,8 @@ pub enum ObligationCauseCode<'tcx> { tail_defines_return_position_impl_trait: Option, }, + IfChainCoerce(Box>), + /// Computing common supertype of an if expression with no else counter-part IfExpressionWithNoElse, @@ -551,6 +553,20 @@ pub struct MatchExpressionArmCause<'tcx> { pub tail_defines_return_position_impl_trait: Option, } +#[derive(Clone, Debug, PartialEq, Eq, StableHash, TyEncodable, TyDecodable)] +#[derive(TypeVisitable, TypeFoldable)] +pub struct IfChainCoerceCause<'tcx> { + /// Outermost `if` of the chain, for the outer "incompatible types" label. + pub outer_if_expr_id: HirId, + pub source_branch_expr_id: HirId, + pub source_branch_ty: Ty<'tcx>, + pub source_branch_span: Span, + pub target_branch_expr_id: HirId, + pub target_branch_ty: Ty<'tcx>, + pub target_branch_span: Span, + pub tail_defines_return_position_impl_trait: Option, +} + /// Information about the origin expression of a pattern, relevant to diagnostics. /// Fields here refer to the scrutinee of a pattern. /// If the scrutinee isn't given in the diagnostic, then this won't exist. diff --git a/compiler/rustc_trait_selection/src/error_reporting/infer/mod.rs b/compiler/rustc_trait_selection/src/error_reporting/infer/mod.rs index 21951cee6d5ab..09d3c61399b93 100644 --- a/compiler/rustc_trait_selection/src/error_reporting/infer/mod.rs +++ b/compiler/rustc_trait_selection/src/error_reporting/infer/mod.rs @@ -58,6 +58,7 @@ use rustc_hir::def_id::{CRATE_DEF_ID, DefId}; use rustc_hir::intravisit::Visitor; use rustc_hir::lang_items::LangItem; use rustc_infer::infer::DefineOpaqueTypes; +use rustc_infer::traits::IfChainCoerceCause; use rustc_macros::extension; use rustc_middle::bug; use rustc_middle::traits::PatternOriginExpr; @@ -512,6 +513,69 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> { } } }, + ObligationCauseCode::IfChainCoerce(box IfChainCoerceCause { + outer_if_expr_id, + source_branch_expr_id: prev_branch_expr_id, + source_branch_ty: prev_branch_ty, + source_branch_span: prev_branch_span, + target_branch_expr_id: branch_expr_id, + target_branch_ty: branch_ty, + target_branch_span: branch_span, + .. + }) => { + err.span_label(prev_branch_span, "expected because of this"); + + if let hir::Node::Expr(&hir::Expr { span: expr_span, .. }) = + self.tcx.hir_node(outer_if_expr_id) + && let hir::Node::Expr(&hir::Expr { kind: hir::ExprKind::If(cond, ..), .. }) = + self.tcx.hir_node(outer_if_expr_id) + { + let outer_span = if self.tcx.sess.source_map().is_multiline(expr_span) { + if prev_branch_span.hi() == expr_span.hi() + || branch_span.hi() == expr_span.hi() + { + // Avoid overlapping arrows: shrink to `if `. + Some(expr_span.shrink_to_lo().to(cond.peel_drop_temps().span)) + } else { + Some(expr_span) + } + } else { + None + }; + if let Some(sp) = outer_span { + err.span_label(sp, "`if` and `else` have incompatible types"); + } + } + + let prev_id = if let hir::Node::Expr(hir::Expr { + kind: hir::ExprKind::Block(blk, _), + .. + }) = self.tcx.hir_node(prev_branch_expr_id) + { + blk.hir_id + } else { + prev_branch_expr_id + }; + let new_id = if let hir::Node::Expr(hir::Expr { + kind: hir::ExprKind::Block(blk, _), + .. + }) = self.tcx.hir_node(branch_expr_id) + { + blk.hir_id + } else { + branch_expr_id + }; + if let Some(subdiag) = self.suggest_remove_semi_or_return_binding( + Some(prev_id), + prev_branch_ty, + prev_branch_span, + Some(new_id), + branch_ty, + branch_span, + ) { + err.subdiagnostic(subdiag); + } + } ObligationCauseCode::IfExpression { expr_id, .. } => { let hir::Node::Expr(&hir::Expr { kind: hir::ExprKind::If(cond_expr, then_expr, Some(else_expr)), @@ -2305,7 +2369,7 @@ impl<'tcx> ObligationCause<'tcx> { } _ => ObligationCauseFailureCode::MatchCompat { span, subdiags }, }, - ObligationCauseCode::IfExpression { .. } => { + ObligationCauseCode::IfExpression { .. } | ObligationCauseCode::IfChainCoerce(_) => { ObligationCauseFailureCode::IfElseDifferent { span, subdiags } } ObligationCauseCode::IfExpressionWithNoElse => { diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs index 148f1471b1b66..fa3ea66334cf1 100644 --- a/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs +++ b/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs @@ -3476,6 +3476,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> { ObligationCauseCode::ExprAssignable | ObligationCauseCode::MatchExpressionArm { .. } | ObligationCauseCode::Pattern { .. } + | ObligationCauseCode::IfChainCoerce(_) | ObligationCauseCode::IfExpression { .. } | ObligationCauseCode::IfExpressionWithNoElse | ObligationCauseCode::MainFunctionType diff --git a/tests/ui/inference/deref-suggestion.rs b/tests/ui/inference/deref-suggestion.rs index dc39cc9dbffb0..bed8a9d9ef637 100644 --- a/tests/ui/inference/deref-suggestion.rs +++ b/tests/ui/inference/deref-suggestion.rs @@ -67,8 +67,8 @@ fn main() { let val = if true { *a } else if true { - //~^ ERROR incompatible types b + //~^ ERROR incompatible types } else { &0 }; diff --git a/tests/ui/inference/deref-suggestion.stderr b/tests/ui/inference/deref-suggestion.stderr index 027902a9f31e2..48ad7d11975cf 100644 --- a/tests/ui/inference/deref-suggestion.stderr +++ b/tests/ui/inference/deref-suggestion.stderr @@ -165,20 +165,24 @@ LL | *b | + error[E0308]: `if` and `else` have incompatible types - --> $DIR/deref-suggestion.rs:69:12 + --> $DIR/deref-suggestion.rs:70:9 | LL | let val = if true { - | ------- `if` and `else` have incompatible types -LL | *a - | -- expected because of this -LL | } else if true { - | ____________^ -LL | | + | _______________- +LL | | *a + | | -- expected because of this +LL | | } else if true { LL | | b -LL | | } else { + | | ^ expected `i32`, found `&{integer}` +... | LL | | &0 LL | | }; - | |_____^ expected `i32`, found `&{integer}` + | |_____- `if` and `else` have incompatible types + | +help: consider dereferencing the borrow + | +LL | *b + | + error[E0308]: mismatched types --> $DIR/deref-suggestion.rs:81:15 diff --git a/tests/ui/typeck/consider-borrowing-141810-1.rs b/tests/ui/typeck/consider-borrowing-141810-1.rs index 94c2d69091517..1b1d4312b4e3c 100644 --- a/tests/ui/typeck/consider-borrowing-141810-1.rs +++ b/tests/ui/typeck/consider-borrowing-141810-1.rs @@ -1,8 +1,9 @@ fn main() { let x = if true { &true - } else if false { //~ ERROR `if` and `else` have incompatible types [E0308] - true //~ HELP consider borrowing here + } else if false { + true //~ ERROR `if` and `else` have incompatible types [E0308] + //~^ HELP consider borrowing here } else { true }; diff --git a/tests/ui/typeck/consider-borrowing-141810-1.stderr b/tests/ui/typeck/consider-borrowing-141810-1.stderr index 35ca6793eee0d..3de8ccea0bfb9 100644 --- a/tests/ui/typeck/consider-borrowing-141810-1.stderr +++ b/tests/ui/typeck/consider-borrowing-141810-1.stderr @@ -1,24 +1,22 @@ error[E0308]: `if` and `else` have incompatible types - --> $DIR/consider-borrowing-141810-1.rs:4:12 + --> $DIR/consider-borrowing-141810-1.rs:5:9 | LL | let x = if true { - | ------- `if` and `else` have incompatible types -LL | &true - | ----- expected because of this -LL | } else if false { - | ____________^ + | _____________- +LL | | &true + | | ----- expected because of this +LL | | } else if false { LL | | true -LL | | } else { + | | ^^^^ expected `&bool`, found `bool` +... | LL | | true LL | | }; - | |_____^ expected `&bool`, found `bool` + | |_____- `if` and `else` have incompatible types | help: consider borrowing here | -LL ~ &true -LL | } else { -LL ~ &true - | +LL | &true + | + error: aborting due to 1 previous error diff --git a/tests/ui/typeck/if-else-type-mismatch-chain-nested.rs b/tests/ui/typeck/if-else-type-mismatch-chain-nested.rs new file mode 100644 index 0000000000000..52bd4c12bd7a9 --- /dev/null +++ b/tests/ui/typeck/if-else-type-mismatch-chain-nested.rs @@ -0,0 +1,21 @@ +fn main() { + let oa = Some(1); + let oa2 = Some(1); + let _v = if let Some(a) = oa { + Some(&a) + } else if let Some(a) = oa2 { + let _f = 1; + + let _h = if true { + 1 + } else if true { + "2" //~ ERROR `if` and `else` have incompatible types [E0308] + } else { + 3 + }; + + &Some(a) //~ ERROR `if` and `else` have incompatible types [E0308] + } else { + None + }; +} diff --git a/tests/ui/typeck/if-else-type-mismatch-chain-nested.stderr b/tests/ui/typeck/if-else-type-mismatch-chain-nested.stderr new file mode 100644 index 0000000000000..c002a18699095 --- /dev/null +++ b/tests/ui/typeck/if-else-type-mismatch-chain-nested.stderr @@ -0,0 +1,43 @@ +error[E0308]: `if` and `else` have incompatible types + --> $DIR/if-else-type-mismatch-chain-nested.rs:12:13 + | +LL | let _h = if true { + | __________________- +LL | | 1 + | | - expected because of this +LL | | } else if true { +LL | | "2" + | | ^^^ expected integer, found `&str` +LL | | } else { +LL | | 3 +LL | | }; + | |_________- `if` and `else` have incompatible types + +error[E0308]: `if` and `else` have incompatible types + --> $DIR/if-else-type-mismatch-chain-nested.rs:17:9 + | +LL | let _v = if let Some(a) = oa { + | ______________- +LL | | Some(&a) + | | -------- expected because of this +LL | | } else if let Some(a) = oa2 { +LL | | let _f = 1; +... | +LL | | &Some(a) + | | ^^^^^^^^ expected `Option<&{integer}>`, found `&Option<{integer}>` +LL | | } else { +LL | | None +LL | | }; + | |_____- `if` and `else` have incompatible types + | + = note: expected enum `Option<&{integer}>` + found reference `&Option<{integer}>` +help: try using `.as_ref()` to convert `&Option<{integer}>` to `Option<&{integer}>` + | +LL - &Some(a) +LL + Some(a).as_ref() + | + +error: aborting due to 2 previous errors + +For more information about this error, try `rustc --explain E0308`. diff --git a/tests/ui/typeck/if-else-type-mismatch-chain.rs b/tests/ui/typeck/if-else-type-mismatch-chain.rs new file mode 100644 index 0000000000000..7a4c14f9acb76 --- /dev/null +++ b/tests/ui/typeck/if-else-type-mismatch-chain.rs @@ -0,0 +1,11 @@ +fn main() { + let oa = Some(1); + let oa2 = Some(1); + let _v = if let Some(a) = oa { + Some(&a) + } else if let Some(a) = oa2 { + &Some(a) //~ ERROR `if` and `else` have incompatible types [E0308] + } else { + None + }; +} diff --git a/tests/ui/typeck/if-else-type-mismatch-chain.stderr b/tests/ui/typeck/if-else-type-mismatch-chain.stderr new file mode 100644 index 0000000000000..890a7186e0c37 --- /dev/null +++ b/tests/ui/typeck/if-else-type-mismatch-chain.stderr @@ -0,0 +1,26 @@ +error[E0308]: `if` and `else` have incompatible types + --> $DIR/if-else-type-mismatch-chain.rs:7:9 + | +LL | let _v = if let Some(a) = oa { + | ______________- +LL | | Some(&a) + | | -------- expected because of this +LL | | } else if let Some(a) = oa2 { +LL | | &Some(a) + | | ^^^^^^^^ expected `Option<&{integer}>`, found `&Option<{integer}>` +LL | | } else { +LL | | None +LL | | }; + | |_____- `if` and `else` have incompatible types + | + = note: expected enum `Option<&{integer}>` + found reference `&Option<{integer}>` +help: try using `.as_ref()` to convert `&Option<{integer}>` to `Option<&{integer}>` + | +LL - &Some(a) +LL + Some(a).as_ref() + | + +error: aborting due to 1 previous error + +For more information about this error, try `rustc --explain E0308`.