diff options
| -rw-r--r-- | src/librustc_typeck/check/cast.rs | 4 | ||||
| -rw-r--r-- | src/librustc_typeck/check/mod.rs | 2 | ||||
| -rw-r--r-- | src/test/run-pass/cast.rs | 5 | ||||
| -rw-r--r-- | src/test/ui/order-dependent-cast-inference.rs | 18 | ||||
| -rw-r--r-- | src/test/ui/order-dependent-cast-inference.stderr | 13 |
5 files changed, 39 insertions, 3 deletions
diff --git a/src/librustc_typeck/check/cast.rs b/src/librustc_typeck/check/cast.rs index 31f418df902..7ebacc92bab 100644 --- a/src/librustc_typeck/check/cast.rs +++ b/src/librustc_typeck/check/cast.rs @@ -389,8 +389,8 @@ impl<'a, 'gcx, 'tcx> CastCheck<'tcx> { } pub fn check(mut self, fcx: &FnCtxt<'a, 'gcx, 'tcx>) { - self.expr_ty = fcx.resolve_type_vars_if_possible(&self.expr_ty); - self.cast_ty = fcx.resolve_type_vars_if_possible(&self.cast_ty); + self.expr_ty = fcx.structurally_resolved_type(self.span, self.expr_ty); + self.cast_ty = fcx.structurally_resolved_type(self.span, self.cast_ty); debug!("check_cast({}, {:?} as {:?})", self.expr.id, diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs index e5d3e84e840..69879bbe85d 100644 --- a/src/librustc_typeck/check/mod.rs +++ b/src/librustc_typeck/check/mod.rs @@ -3639,7 +3639,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> { needs); if !oprnd_t.references_error() { - oprnd_t = self.resolve_type_vars_with_obligations(&oprnd_t); + oprnd_t = self.structurally_resolved_type(expr.span, oprnd_t); match unop { hir::UnDeref => { if let Some(mt) = oprnd_t.builtin_deref(true) { diff --git a/src/test/run-pass/cast.rs b/src/test/run-pass/cast.rs index bb60626a4bf..80fa5362a8b 100644 --- a/src/test/run-pass/cast.rs +++ b/src/test/run-pass/cast.rs @@ -19,4 +19,9 @@ pub fn main() { assert_eq!(i as u8 as i8, 'Q' as u8 as i8); assert_eq!(0x51 as char, 'Q'); assert_eq!(0 as u32, false as u32); + + // Test that `_` is correctly inferred. + let x = &"hello"; + let mut y = x as *const _; + y = 0 as *const _; } diff --git a/src/test/ui/order-dependent-cast-inference.rs b/src/test/ui/order-dependent-cast-inference.rs new file mode 100644 index 00000000000..afcd402343b --- /dev/null +++ b/src/test/ui/order-dependent-cast-inference.rs @@ -0,0 +1,18 @@ +// Copyright 2018 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or +// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +fn main() { + // Tests case where inference fails due to the order in which casts are checked. + // Ideally this would compile, see #48270. + let x = &"hello"; + let mut y = 0 as *const _; + //~^ ERROR cannot cast to a pointer of an unknown kind + y = x as *const _; +} diff --git a/src/test/ui/order-dependent-cast-inference.stderr b/src/test/ui/order-dependent-cast-inference.stderr new file mode 100644 index 00000000000..556acc87cff --- /dev/null +++ b/src/test/ui/order-dependent-cast-inference.stderr @@ -0,0 +1,13 @@ +error[E0641]: cannot cast to a pointer of an unknown kind + --> $DIR/order-dependent-cast-inference.rs:15:17 + | +LL | let mut y = 0 as *const _; + | ^^^^^-------- + | | + | help: consider giving more type information + | + = note: The type information given here is insufficient to check whether the pointer cast is valid + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0641`. |