From 2e781ddacc126b24df93f7b547ced542262f12a2 Mon Sep 17 00:00:00 2001 From: David Wood Date: Fri, 12 Jun 2020 17:42:08 +0100 Subject: [PATCH] lint: normalize projections using opaque types This commit normalizes projections which contain opaque types (opaque types are otherwise linted against, which is would have previously made the test cases added in this commit fail). Signed-off-by: David Wood --- src/librustc_lint/types.rs | 27 +++++++++++------ src/test/ui/lint/lint-ctypes-73251-1.rs | 24 ++++++++++++++++ src/test/ui/lint/lint-ctypes-73251-1.stderr | 15 ++++++++++ src/test/ui/lint/lint-ctypes-73251-2.rs | 32 +++++++++++++++++++++ src/test/ui/lint/lint-ctypes-73251-2.stderr | 15 ++++++++++ src/test/ui/lint/lint-ctypes-73251.rs | 22 ++++++++++++++ 6 files changed, 127 insertions(+), 8 deletions(-) create mode 100644 src/test/ui/lint/lint-ctypes-73251-1.rs create mode 100644 src/test/ui/lint/lint-ctypes-73251-1.stderr create mode 100644 src/test/ui/lint/lint-ctypes-73251-2.rs create mode 100644 src/test/ui/lint/lint-ctypes-73251-2.stderr create mode 100644 src/test/ui/lint/lint-ctypes-73251.rs diff --git a/src/librustc_lint/types.rs b/src/librustc_lint/types.rs index d92c1131ff9fd..a19c9a3557996 100644 --- a/src/librustc_lint/types.rs +++ b/src/librustc_lint/types.rs @@ -895,22 +895,33 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> { } fn check_for_opaque_ty(&mut self, sp: Span, ty: Ty<'tcx>) -> bool { - struct ProhibitOpaqueTypes<'tcx> { + struct ProhibitOpaqueTypes<'a, 'tcx> { + cx: &'a LateContext<'a, 'tcx>, ty: Option>, }; - impl<'tcx> ty::fold::TypeVisitor<'tcx> for ProhibitOpaqueTypes<'tcx> { + impl<'a, 'tcx> ty::fold::TypeVisitor<'tcx> for ProhibitOpaqueTypes<'a, 'tcx> { fn visit_ty(&mut self, ty: Ty<'tcx>) -> bool { - if let ty::Opaque(..) = ty.kind { - self.ty = Some(ty); - true - } else { - ty.super_visit_with(self) + match ty.kind { + ty::Opaque(..) => { + self.ty = Some(ty); + true + } + // Consider opaque types within projections FFI-safe if they do not normalize + // to more opaque types. + ty::Projection(..) => { + let ty = self.cx.tcx.normalize_erasing_regions(self.cx.param_env, ty); + + // If `ty` is a opaque type directly then `super_visit_with` won't invoke + // this function again. + if ty.has_opaque_types() { self.visit_ty(ty) } else { false } + } + _ => ty.super_visit_with(self), } } } - let mut visitor = ProhibitOpaqueTypes { ty: None }; + let mut visitor = ProhibitOpaqueTypes { cx: self.cx, ty: None }; ty.visit_with(&mut visitor); if let Some(ty) = visitor.ty { self.emit_ffi_unsafe_type_lint(ty, sp, "opaque types have no C equivalent", None); diff --git a/src/test/ui/lint/lint-ctypes-73251-1.rs b/src/test/ui/lint/lint-ctypes-73251-1.rs new file mode 100644 index 0000000000000..2ce80982f5ca1 --- /dev/null +++ b/src/test/ui/lint/lint-ctypes-73251-1.rs @@ -0,0 +1,24 @@ +#![feature(type_alias_impl_trait)] +#![deny(improper_ctypes)] + +pub trait Baz { } + +impl Baz for u32 { } + +type Qux = impl Baz; + +pub trait Foo { + type Assoc; +} + +impl Foo for u32 { + type Assoc = Qux; +} + +fn assign() -> Qux { 1 } + +extern "C" { + pub fn lint_me() -> ::Assoc; //~ ERROR: uses type `impl Baz` +} + +fn main() {} diff --git a/src/test/ui/lint/lint-ctypes-73251-1.stderr b/src/test/ui/lint/lint-ctypes-73251-1.stderr new file mode 100644 index 0000000000000..0b4237bb96fb7 --- /dev/null +++ b/src/test/ui/lint/lint-ctypes-73251-1.stderr @@ -0,0 +1,15 @@ +error: `extern` block uses type `impl Baz`, which is not FFI-safe + --> $DIR/lint-ctypes-73251-1.rs:21:25 + | +LL | pub fn lint_me() -> ::Assoc; + | ^^^^^^^^^^^^^^^^^^^ not FFI-safe + | +note: the lint level is defined here + --> $DIR/lint-ctypes-73251-1.rs:2:9 + | +LL | #![deny(improper_ctypes)] + | ^^^^^^^^^^^^^^^ + = note: opaque types have no C equivalent + +error: aborting due to previous error + diff --git a/src/test/ui/lint/lint-ctypes-73251-2.rs b/src/test/ui/lint/lint-ctypes-73251-2.rs new file mode 100644 index 0000000000000..3427c657b42ac --- /dev/null +++ b/src/test/ui/lint/lint-ctypes-73251-2.rs @@ -0,0 +1,32 @@ +#![feature(type_alias_impl_trait)] +#![deny(improper_ctypes)] + +pub trait TraitA { + type Assoc; +} + +impl TraitA for u32 { + type Assoc = u32; +} + +pub trait TraitB { + type Assoc; +} + +impl TraitB for T where T: TraitA { + type Assoc = ::Assoc; +} + +type AliasA = impl TraitA; + +type AliasB = impl TraitB; + +fn use_of_a() -> AliasA { 3 } + +fn use_of_b() -> AliasB { 3 } + +extern "C" { + pub fn lint_me() -> ::Assoc; //~ ERROR: uses type `impl TraitA` +} + +fn main() {} diff --git a/src/test/ui/lint/lint-ctypes-73251-2.stderr b/src/test/ui/lint/lint-ctypes-73251-2.stderr new file mode 100644 index 0000000000000..43f7629b043a9 --- /dev/null +++ b/src/test/ui/lint/lint-ctypes-73251-2.stderr @@ -0,0 +1,15 @@ +error: `extern` block uses type `impl TraitA`, which is not FFI-safe + --> $DIR/lint-ctypes-73251-2.rs:29:25 + | +LL | pub fn lint_me() -> ::Assoc; + | ^^^^^^^^^^^^^^^^^^^^^^^^^ not FFI-safe + | +note: the lint level is defined here + --> $DIR/lint-ctypes-73251-2.rs:2:9 + | +LL | #![deny(improper_ctypes)] + | ^^^^^^^^^^^^^^^ + = note: opaque types have no C equivalent + +error: aborting due to previous error + diff --git a/src/test/ui/lint/lint-ctypes-73251.rs b/src/test/ui/lint/lint-ctypes-73251.rs new file mode 100644 index 0000000000000..ebc2ca77b67a1 --- /dev/null +++ b/src/test/ui/lint/lint-ctypes-73251.rs @@ -0,0 +1,22 @@ +// check-pass + +#![feature(type_alias_impl_trait)] +#![deny(improper_ctypes)] + +pub trait Foo { + type Assoc; +} + +impl Foo for () { + type Assoc = u32; +} + +type Bar = impl Foo; + +fn assign() -> Bar {} + +extern "C" { + pub fn lint_me() -> ::Assoc; +} + +fn main() {}