diff --git a/src/librustc_typeck/check/cast.rs b/src/librustc_typeck/check/cast.rs index 69174dacaaa..5c255364311 100644 --- a/src/librustc_typeck/check/cast.rs +++ b/src/librustc_typeck/check/cast.rs @@ -40,9 +40,11 @@ use super::{Diverges, FnCtxt}; -use lint; +use errors::DiagnosticBuilder; use hir::def_id::DefId; +use lint; use rustc::hir; +use rustc::session::Session; use rustc::traits; use rustc::ty::{self, Ty, TypeFoldable}; use rustc::ty::cast::{CastKind, CastTy}; @@ -112,6 +114,18 @@ enum CastError { NonScalar, } +fn make_invalid_casting_error<'a, 'gcx, 'tcx>(sess: &'a Session, + span: Span, + expr_ty: Ty<'tcx>, + cast_ty: Ty<'tcx>, + fcx: &FnCtxt<'a, 'gcx, 'tcx>) + -> DiagnosticBuilder<'a> { + struct_span_err!(sess, span, E0606, + "casting `{}` as `{}` is invalid", + fcx.ty_to_string(expr_ty), + fcx.ty_to_string(cast_ty)) +} + impl<'a, 'gcx, 'tcx> CastCheck<'tcx> { pub fn new(fcx: &FnCtxt<'a, 'gcx, 'tcx>, expr: &'tcx hir::Expr, @@ -146,14 +160,9 @@ impl<'a, 'gcx, 'tcx> CastCheck<'tcx> { match e { CastError::NeedDeref => { let error_span = self.span; + let mut err = make_invalid_casting_error(fcx.tcx.sess, self.span, self.expr_ty, + self.cast_ty, fcx); let cast_ty = fcx.ty_to_string(self.cast_ty); - let mut err = fcx.type_error_struct(error_span, - |actual| { - format!("casting `{}` as `{}` is invalid", - actual, - cast_ty) - }, - self.expr_ty); err.span_label(error_span, format!("cannot cast `{}` as `{}`", fcx.ty_to_string(self.expr_ty), @@ -166,13 +175,8 @@ impl<'a, 'gcx, 'tcx> CastCheck<'tcx> { } CastError::NeedViaThinPtr | CastError::NeedViaPtr => { - let mut err = fcx.type_error_struct(self.span, - |actual| { - format!("casting `{}` as `{}` is invalid", - actual, - fcx.ty_to_string(self.cast_ty)) - }, - self.expr_ty); + let mut err = make_invalid_casting_error(fcx.tcx.sess, self.span, self.expr_ty, + self.cast_ty, fcx); if self.cast_ty.is_uint() { err.help(&format!("cast through {} first", match e { @@ -184,13 +188,7 @@ impl<'a, 'gcx, 'tcx> CastCheck<'tcx> { err.emit(); } CastError::NeedViaInt => { - fcx.type_error_struct(self.span, - |actual| { - format!("casting `{}` as `{}` is invalid", - actual, - fcx.ty_to_string(self.cast_ty)) - }, - self.expr_ty) + make_invalid_casting_error(fcx.tcx.sess, self.span, self.expr_ty, self.cast_ty, fcx) .help(&format!("cast through {} first", match e { CastError::NeedViaInt => "an integer", @@ -198,6 +196,15 @@ impl<'a, 'gcx, 'tcx> CastCheck<'tcx> { })) .emit(); } + CastError::IllegalCast => { + make_invalid_casting_error(fcx.tcx.sess, self.span, self.expr_ty, self.cast_ty, fcx) + .emit(); + } + CastError::DifferingKinds => { + make_invalid_casting_error(fcx.tcx.sess, self.span, self.expr_ty, self.cast_ty, fcx) + .note("vtable kinds may not match") + .emit(); + } CastError::CastToBool => { struct_span_err!(fcx.tcx.sess, self.span, E0054, "cannot cast as `bool`") .span_label(self.span, "unsupported cast") @@ -217,15 +224,6 @@ impl<'a, 'gcx, 'tcx> CastCheck<'tcx> { primitive types. Consider using the `From` trait") .emit(); } - CastError::IllegalCast => { - fcx.type_error_message(self.span, - |actual| { - format!("casting `{}` as `{}` is invalid", - actual, - fcx.ty_to_string(self.cast_ty)) - }, - self.expr_ty); - } CastError::SizedUnsizedCast => { fcx.type_error_message(self.span, |actual| { @@ -236,17 +234,6 @@ impl<'a, 'gcx, 'tcx> CastCheck<'tcx> { }, self.expr_ty) } - CastError::DifferingKinds => { - fcx.type_error_struct(self.span, - |actual| { - format!("casting `{}` as `{}` is invalid", - actual, - fcx.ty_to_string(self.cast_ty)) - }, - self.expr_ty) - .note("vtable kinds may not match") - .emit(); - } } } diff --git a/src/librustc_typeck/diagnostics.rs b/src/librustc_typeck/diagnostics.rs index a787aadc678..d3138af978a 100644 --- a/src/librustc_typeck/diagnostics.rs +++ b/src/librustc_typeck/diagnostics.rs @@ -4251,6 +4251,25 @@ v as *const i8; // ok! ``` "##, +E0606: r##" +An incompatible cast was attempted. + +Erroneous code example: + +```compile_fail,E0606 +let x = &0u8; // Here, `x` is a `&u8`. +let y: u32 = x as u32; // error: casting `&u8` as `u32` is invalid +``` + +When casting, keep in mind that only primitive types cast be casted into each +others. Example: + +``` +let x = &0u8; +let y: u32 = *x as u32; // We dereference it first and then cast it. +``` +"##, + E0609: r##" Attempted to access a non-existent field in a struct. diff --git a/src/test/compile-fail/E0606.rs b/src/test/compile-fail/E0606.rs new file mode 100644 index 00000000000..55071736bfe --- /dev/null +++ b/src/test/compile-fail/E0606.rs @@ -0,0 +1,13 @@ +// Copyright 2017 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 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +fn main() { + &0u8 as u8; //~ ERROR E0606 +} diff --git a/src/test/ui/mismatched_types/cast-rfc0401.stderr b/src/test/ui/mismatched_types/cast-rfc0401.stderr index c79d242dc5e..b4c3106253e 100644 --- a/src/test/ui/mismatched_types/cast-rfc0401.stderr +++ b/src/test/ui/mismatched_types/cast-rfc0401.stderr @@ -1,4 +1,4 @@ -error: casting `*const U` as `*const V` is invalid +error[E0606]: casting `*const U` as `*const V` is invalid --> $DIR/cast-rfc0401.rs:13:5 | 13 | u as *const V @@ -6,7 +6,7 @@ error: casting `*const U` as `*const V` is invalid | = note: vtable kinds may not match -error: casting `*const U` as `*const str` is invalid +error[E0606]: casting `*const U` as `*const str` is invalid --> $DIR/cast-rfc0401.rs:18:5 | 18 | u as *const str @@ -60,19 +60,19 @@ error[E0605]: non-scalar cast: `std::option::Option<&*const u8>` as `*const u8` | = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait -error: casting `*const u8` as `f32` is invalid +error[E0606]: casting `*const u8` as `f32` is invalid --> $DIR/cast-rfc0401.rs:45:13 | 45 | let _ = v as f32; | ^^^^^^^^ -error: casting `fn() {main}` as `f64` is invalid +error[E0606]: casting `fn() {main}` as `f64` is invalid --> $DIR/cast-rfc0401.rs:46:13 | 46 | let _ = main as f64; | ^^^^^^^^^^^ -error: casting `&*const u8` as `usize` is invalid +error[E0606]: casting `&*const u8` as `usize` is invalid --> $DIR/cast-rfc0401.rs:47:13 | 47 | let _ = &v as usize; @@ -80,7 +80,7 @@ error: casting `&*const u8` as `usize` is invalid | = help: cast through a raw pointer first -error: casting `f32` as `*const u8` is invalid +error[E0606]: casting `f32` as `*const u8` is invalid --> $DIR/cast-rfc0401.rs:48:13 | 48 | let _ = f as *const u8; @@ -108,7 +108,7 @@ error[E0604]: only `u8` can be cast as `char`, not `u32` 51 | let _ = 0x61u32 as char; | ^^^^^^^^^^^^^^^ -error: casting `bool` as `f32` is invalid +error[E0606]: casting `bool` as `f32` is invalid --> $DIR/cast-rfc0401.rs:53:13 | 53 | let _ = false as f32; @@ -116,7 +116,7 @@ error: casting `bool` as `f32` is invalid | = help: cast through an integer first -error: casting `E` as `f32` is invalid +error[E0606]: casting `E` as `f32` is invalid --> $DIR/cast-rfc0401.rs:54:13 | 54 | let _ = E::A as f32; @@ -124,7 +124,7 @@ error: casting `E` as `f32` is invalid | = help: cast through an integer first -error: casting `char` as `f32` is invalid +error[E0606]: casting `char` as `f32` is invalid --> $DIR/cast-rfc0401.rs:55:13 | 55 | let _ = 'a' as f32; @@ -132,25 +132,25 @@ error: casting `char` as `f32` is invalid | = help: cast through an integer first -error: casting `bool` as `*const u8` is invalid +error[E0606]: casting `bool` as `*const u8` is invalid --> $DIR/cast-rfc0401.rs:57:13 | 57 | let _ = false as *const u8; | ^^^^^^^^^^^^^^^^^^ -error: casting `E` as `*const u8` is invalid +error[E0606]: casting `E` as `*const u8` is invalid --> $DIR/cast-rfc0401.rs:58:13 | 58 | let _ = E::A as *const u8; | ^^^^^^^^^^^^^^^^^ -error: casting `char` as `*const u8` is invalid +error[E0606]: casting `char` as `*const u8` is invalid --> $DIR/cast-rfc0401.rs:59:13 | 59 | let _ = 'a' as *const u8; | ^^^^^^^^^^^^^^^^ -error: casting `usize` as `*const [u8]` is invalid +error[E0606]: casting `usize` as `*const [u8]` is invalid --> $DIR/cast-rfc0401.rs:61:13 | 61 | let _ = 42usize as *const [u8]; @@ -162,37 +162,37 @@ error: cannot cast thin pointer `*const u8` to fat pointer `*const [u8]` 62 | let _ = v as *const [u8]; | ^^^^^^^^^^^^^^^^ -error: casting `&Foo` as `*const str` is invalid +error[E0606]: casting `&Foo` as `*const str` is invalid --> $DIR/cast-rfc0401.rs:64:13 | 64 | let _ = foo as *const str; | ^^^^^^^^^^^^^^^^^ -error: casting `&Foo` as `*mut str` is invalid +error[E0606]: casting `&Foo` as `*mut str` is invalid --> $DIR/cast-rfc0401.rs:65:13 | 65 | let _ = foo as *mut str; | ^^^^^^^^^^^^^^^ -error: casting `fn() {main}` as `*mut str` is invalid +error[E0606]: casting `fn() {main}` as `*mut str` is invalid --> $DIR/cast-rfc0401.rs:66:13 | 66 | let _ = main as *mut str; | ^^^^^^^^^^^^^^^^ -error: casting `&f32` as `*mut f32` is invalid +error[E0606]: casting `&f32` as `*mut f32` is invalid --> $DIR/cast-rfc0401.rs:67:13 | 67 | let _ = &f as *mut f32; | ^^^^^^^^^^^^^^ -error: casting `&f32` as `*const f64` is invalid +error[E0606]: casting `&f32` as `*const f64` is invalid --> $DIR/cast-rfc0401.rs:68:13 | 68 | let _ = &f as *const f64; | ^^^^^^^^^^^^^^^^ -error: casting `*const [i8]` as `usize` is invalid +error[E0606]: casting `*const [i8]` as `usize` is invalid --> $DIR/cast-rfc0401.rs:69:13 | 69 | let _ = fat_sv as usize; @@ -200,7 +200,7 @@ error: casting `*const [i8]` as `usize` is invalid | = help: cast through a thin pointer first -error: casting `*const Foo` as `*const [u16]` is invalid +error[E0606]: casting `*const Foo` as `*const [u16]` is invalid --> $DIR/cast-rfc0401.rs:78:13 | 78 | let _ = cf as *const [u16]; @@ -208,7 +208,7 @@ error: casting `*const Foo` as `*const [u16]` is invalid | = note: vtable kinds may not match -error: casting `*const Foo` as `*const Bar` is invalid +error[E0606]: casting `*const Foo` as `*const Bar` is invalid --> $DIR/cast-rfc0401.rs:79:13 | 79 | let _ = cf as *const Bar; @@ -234,7 +234,7 @@ error[E0277]: the trait bound `str: std::marker::Sized` is not satisfied = help: the trait `std::marker::Sized` is not implemented for `str` = note: required for the cast to the object type `Foo` -error: casting `&{float}` as `f32` is invalid +error[E0606]: casting `&{float}` as `f32` is invalid --> $DIR/cast-rfc0401.rs:81:30 | 81 | vec![0.0].iter().map(|s| s as f32).collect::>();