also query type_uninhabited_from

rust-lang · Sep 27, 2022 · 67fd09d · 67fd09d
1 parent c19daa4
commit 67fd09d
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Showing 5 changed files with 49 additions and 40 deletions.
diff --git a/compiler/rustc_lint/src/builtin.rs b/compiler/rustc_lint/src/builtin.rs
@@ -2425,8 +2425,12 @@ impl<'tcx> LateLintPass<'tcx> for InvalidValue {
         }
 
         /// Determines whether the given type is inhabited. `None` means that we don't know.
-        fn ty_inhabited(ty: Ty<'_>) -> Option<bool> {
+        fn ty_inhabited<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> Option<bool> {
             use rustc_type_ir::sty::TyKind::*;
+            if !cx.tcx.type_uninhabited_from(cx.param_env.and(ty)).is_empty() {
+                // This is definitely uninhabited from some module.
+                return Some(false);
+            }
             match ty.kind() {
                 Never => Some(false),
                 Int(_) | Uint(_) | Float(_) | Bool | Char | RawPtr(_) => Some(true),
@@ -2436,10 +2440,13 @@ impl<'tcx> LateLintPass<'tcx> for InvalidValue {
             }
         }
         /// Determines whether a product type formed from a list of types is inhabited.
-        fn tys_inhabited<'tcx>(tys: impl Iterator<Item = Ty<'tcx>>) -> Option<bool> {
+        fn tys_inhabited<'tcx>(
+            cx: &LateContext<'tcx>,
+            tys: impl Iterator<Item = Ty<'tcx>>,
+        ) -> Option<bool> {
             let mut definitely_inhabited = true; // with no fields, we are definitely inhabited.
             for ty in tys {
-                match ty_inhabited(ty) {
+                match ty_inhabited(cx, ty) {
                     // If any type is uninhabited, the product is uninhabited.
                     Some(false) => return Some(false),
                     // Otherwise go searching for a `None`.
@@ -2550,6 +2557,7 @@ impl<'tcx> LateLintPass<'tcx> for InvalidValue {
                     let span = cx.tcx.def_span(adt_def.did());
                     let mut potential_variants = adt_def.variants().iter().filter_map(|variant| {
                         let inhabited = tys_inhabited(
+                            cx,
                             variant.fields.iter().map(|field| field.ty(cx.tcx, substs)),
                         );
                         let definitely_inhabited = match inhabited {

diff --git a/src/test/ui/consts/const-eval/ub-enum.32bit.stderr b/src/test/ui/consts/const-eval/ub-enum.32bit.stderr
@@ -1,5 +1,5 @@
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-enum.rs:23:1
+  --> $DIR/ub-enum.rs:24:1
    |
 LL | const BAD_ENUM: Enum = unsafe { mem::transmute(1usize) };
    | ^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<enum-tag>: encountered 0x00000001, but expected a valid enum tag
@@ -10,7 +10,7 @@ LL | const BAD_ENUM: Enum = unsafe { mem::transmute(1usize) };
            }
 
 error: any use of this value will cause an error
-  --> $DIR/ub-enum.rs:26:1
+  --> $DIR/ub-enum.rs:27:1
    |
 LL | const BAD_ENUM_PTR: Enum = unsafe { mem::transmute(&1) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -22,7 +22,7 @@ LL | const BAD_ENUM_PTR: Enum = unsafe { mem::transmute(&1) };
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error: any use of this value will cause an error
-  --> $DIR/ub-enum.rs:30:1
+  --> $DIR/ub-enum.rs:31:1
    |
 LL | const BAD_ENUM_WRAPPED: Wrap<Enum> = unsafe { mem::transmute(&1) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -33,7 +33,7 @@ LL | const BAD_ENUM_WRAPPED: Wrap<Enum> = unsafe { mem::transmute(&1) };
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-enum.rs:43:1
+  --> $DIR/ub-enum.rs:44:1
    |
 LL | const BAD_ENUM2: Enum2 = unsafe { mem::transmute(0usize) };
    | ^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<enum-tag>: encountered 0x00000000, but expected a valid enum tag
@@ -44,7 +44,7 @@ LL | const BAD_ENUM2: Enum2 = unsafe { mem::transmute(0usize) };
            }
 
 error: any use of this value will cause an error
-  --> $DIR/ub-enum.rs:45:1
+  --> $DIR/ub-enum.rs:46:1
    |
 LL | const BAD_ENUM2_PTR: Enum2 = unsafe { mem::transmute(&0) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -55,7 +55,7 @@ LL | const BAD_ENUM2_PTR: Enum2 = unsafe { mem::transmute(&0) };
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error: any use of this value will cause an error
-  --> $DIR/ub-enum.rs:49:1
+  --> $DIR/ub-enum.rs:50:1
    |
 LL | const BAD_ENUM2_WRAPPED: Wrap<Enum2> = unsafe { mem::transmute(&0) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -66,13 +66,13 @@ LL | const BAD_ENUM2_WRAPPED: Wrap<Enum2> = unsafe { mem::transmute(&0) };
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-enum.rs:59:42
+  --> $DIR/ub-enum.rs:60:42
    |
 LL | const BAD_ENUM2_UNDEF : Enum2 = unsafe { MaybeUninit { uninit: () }.init };
    |                                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error: any use of this value will cause an error
-  --> $DIR/ub-enum.rs:64:1
+  --> $DIR/ub-enum.rs:65:1
    |
 LL | const BAD_ENUM2_OPTION_PTR: Option<Enum2> = unsafe { mem::transmute(&0) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -83,7 +83,7 @@ LL | const BAD_ENUM2_OPTION_PTR: Option<Enum2> = unsafe { mem::transmute(&0) };
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-enum.rs:82:1
+  --> $DIR/ub-enum.rs:83:1
    |
 LL | const BAD_UNINHABITED_VARIANT1: UninhDiscriminant = unsafe { mem::transmute(1u8) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<enum-variant(B)>.0: encountered a value of the never type `!`
@@ -94,7 +94,7 @@ LL | const BAD_UNINHABITED_VARIANT1: UninhDiscriminant = unsafe { mem::transmute
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-enum.rs:84:1
+  --> $DIR/ub-enum.rs:85:1
    |
 LL | const BAD_UNINHABITED_VARIANT2: UninhDiscriminant = unsafe { mem::transmute(3u8) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<enum-variant(D)>.0: encountered a value of uninhabited type Never
@@ -105,7 +105,7 @@ LL | const BAD_UNINHABITED_VARIANT2: UninhDiscriminant = unsafe { mem::transmute
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-enum.rs:92:1
+  --> $DIR/ub-enum.rs:93:1
    |
 LL | const BAD_OPTION_CHAR: Option<(char, char)> = Some(('x', unsafe { mem::transmute(!0u32) }));
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<enum-variant(Some)>.0.1: encountered 0xffffffff, but expected a valid unicode scalar value (in `0..=0x10FFFF` but not in `0xD800..=0xDFFF`)
@@ -116,13 +116,13 @@ LL | const BAD_OPTION_CHAR: Option<(char, char)> = Some(('x', unsafe { mem::tran
            }
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-enum.rs:97:77
+  --> $DIR/ub-enum.rs:98:77
    |
 LL | const BAD_UNINHABITED_WITH_DATA1: Result<(i32, Never), (i32, !)> = unsafe { mem::transmute(0u64) };
    |                                                                             ^^^^^^^^^^^^^^^^^^^^ transmuting to uninhabited type
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-enum.rs:99:77
+  --> $DIR/ub-enum.rs:100:77
    |
 LL | const BAD_UNINHABITED_WITH_DATA2: Result<(i32, !), (i32, Never)> = unsafe { mem::transmute(0u64) };
    |                                                                             ^^^^^^^^^^^^^^^^^^^^ transmuting to uninhabited type
@@ -132,7 +132,7 @@ error: aborting due to 13 previous errors
 For more information about this error, try `rustc --explain E0080`.
 Future incompatibility report: Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/ub-enum.rs:26:1
+  --> $DIR/ub-enum.rs:27:1
    |
 LL | const BAD_ENUM_PTR: Enum = unsafe { mem::transmute(&1) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -145,7 +145,7 @@ LL | const BAD_ENUM_PTR: Enum = unsafe { mem::transmute(&1) };
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/ub-enum.rs:30:1
+  --> $DIR/ub-enum.rs:31:1
    |
 LL | const BAD_ENUM_WRAPPED: Wrap<Enum> = unsafe { mem::transmute(&1) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -158,7 +158,7 @@ LL | const BAD_ENUM_WRAPPED: Wrap<Enum> = unsafe { mem::transmute(&1) };
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/ub-enum.rs:45:1
+  --> $DIR/ub-enum.rs:46:1
    |
 LL | const BAD_ENUM2_PTR: Enum2 = unsafe { mem::transmute(&0) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -171,7 +171,7 @@ LL | const BAD_ENUM2_PTR: Enum2 = unsafe { mem::transmute(&0) };
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/ub-enum.rs:49:1
+  --> $DIR/ub-enum.rs:50:1
    |
 LL | const BAD_ENUM2_WRAPPED: Wrap<Enum2> = unsafe { mem::transmute(&0) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -184,7 +184,7 @@ LL | const BAD_ENUM2_WRAPPED: Wrap<Enum2> = unsafe { mem::transmute(&0) };
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/ub-enum.rs:64:1
+  --> $DIR/ub-enum.rs:65:1
    |
 LL | const BAD_ENUM2_OPTION_PTR: Option<Enum2> = unsafe { mem::transmute(&0) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes

diff --git a/src/test/ui/consts/const-eval/ub-enum.64bit.stderr b/src/test/ui/consts/const-eval/ub-enum.64bit.stderr
@@ -1,5 +1,5 @@
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-enum.rs:23:1
+  --> $DIR/ub-enum.rs:24:1
    |
 LL | const BAD_ENUM: Enum = unsafe { mem::transmute(1usize) };
    | ^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<enum-tag>: encountered 0x0000000000000001, but expected a valid enum tag
@@ -10,7 +10,7 @@ LL | const BAD_ENUM: Enum = unsafe { mem::transmute(1usize) };
            }
 
 error: any use of this value will cause an error
-  --> $DIR/ub-enum.rs:26:1
+  --> $DIR/ub-enum.rs:27:1
    |
 LL | const BAD_ENUM_PTR: Enum = unsafe { mem::transmute(&1) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -22,7 +22,7 @@ LL | const BAD_ENUM_PTR: Enum = unsafe { mem::transmute(&1) };
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error: any use of this value will cause an error
-  --> $DIR/ub-enum.rs:30:1
+  --> $DIR/ub-enum.rs:31:1
    |
 LL | const BAD_ENUM_WRAPPED: Wrap<Enum> = unsafe { mem::transmute(&1) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -33,7 +33,7 @@ LL | const BAD_ENUM_WRAPPED: Wrap<Enum> = unsafe { mem::transmute(&1) };
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-enum.rs:43:1
+  --> $DIR/ub-enum.rs:44:1
    |
 LL | const BAD_ENUM2: Enum2 = unsafe { mem::transmute(0usize) };
    | ^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<enum-tag>: encountered 0x0000000000000000, but expected a valid enum tag
@@ -44,7 +44,7 @@ LL | const BAD_ENUM2: Enum2 = unsafe { mem::transmute(0usize) };
            }
 
 error: any use of this value will cause an error
-  --> $DIR/ub-enum.rs:45:1
+  --> $DIR/ub-enum.rs:46:1
    |
 LL | const BAD_ENUM2_PTR: Enum2 = unsafe { mem::transmute(&0) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -55,7 +55,7 @@ LL | const BAD_ENUM2_PTR: Enum2 = unsafe { mem::transmute(&0) };
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error: any use of this value will cause an error
-  --> $DIR/ub-enum.rs:49:1
+  --> $DIR/ub-enum.rs:50:1
    |
 LL | const BAD_ENUM2_WRAPPED: Wrap<Enum2> = unsafe { mem::transmute(&0) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -66,13 +66,13 @@ LL | const BAD_ENUM2_WRAPPED: Wrap<Enum2> = unsafe { mem::transmute(&0) };
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-enum.rs:59:42
+  --> $DIR/ub-enum.rs:60:42
    |
 LL | const BAD_ENUM2_UNDEF : Enum2 = unsafe { MaybeUninit { uninit: () }.init };
    |                                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error: any use of this value will cause an error
-  --> $DIR/ub-enum.rs:64:1
+  --> $DIR/ub-enum.rs:65:1
    |
 LL | const BAD_ENUM2_OPTION_PTR: Option<Enum2> = unsafe { mem::transmute(&0) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -83,7 +83,7 @@ LL | const BAD_ENUM2_OPTION_PTR: Option<Enum2> = unsafe { mem::transmute(&0) };
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-enum.rs:82:1
+  --> $DIR/ub-enum.rs:83:1
    |
 LL | const BAD_UNINHABITED_VARIANT1: UninhDiscriminant = unsafe { mem::transmute(1u8) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<enum-variant(B)>.0: encountered a value of the never type `!`
@@ -94,7 +94,7 @@ LL | const BAD_UNINHABITED_VARIANT1: UninhDiscriminant = unsafe { mem::transmute
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-enum.rs:84:1
+  --> $DIR/ub-enum.rs:85:1
    |
 LL | const BAD_UNINHABITED_VARIANT2: UninhDiscriminant = unsafe { mem::transmute(3u8) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<enum-variant(D)>.0: encountered a value of uninhabited type Never
@@ -105,7 +105,7 @@ LL | const BAD_UNINHABITED_VARIANT2: UninhDiscriminant = unsafe { mem::transmute
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-enum.rs:92:1
+  --> $DIR/ub-enum.rs:93:1
    |
 LL | const BAD_OPTION_CHAR: Option<(char, char)> = Some(('x', unsafe { mem::transmute(!0u32) }));
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<enum-variant(Some)>.0.1: encountered 0xffffffff, but expected a valid unicode scalar value (in `0..=0x10FFFF` but not in `0xD800..=0xDFFF`)
@@ -116,13 +116,13 @@ LL | const BAD_OPTION_CHAR: Option<(char, char)> = Some(('x', unsafe { mem::tran
            }
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-enum.rs:97:77
+  --> $DIR/ub-enum.rs:98:77
    |
 LL | const BAD_UNINHABITED_WITH_DATA1: Result<(i32, Never), (i32, !)> = unsafe { mem::transmute(0u64) };
    |                                                                             ^^^^^^^^^^^^^^^^^^^^ transmuting to uninhabited type
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-enum.rs:99:77
+  --> $DIR/ub-enum.rs:100:77
    |
 LL | const BAD_UNINHABITED_WITH_DATA2: Result<(i32, !), (i32, Never)> = unsafe { mem::transmute(0u64) };
    |                                                                             ^^^^^^^^^^^^^^^^^^^^ transmuting to uninhabited type
@@ -132,7 +132,7 @@ error: aborting due to 13 previous errors
 For more information about this error, try `rustc --explain E0080`.
 Future incompatibility report: Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/ub-enum.rs:26:1
+  --> $DIR/ub-enum.rs:27:1
    |
 LL | const BAD_ENUM_PTR: Enum = unsafe { mem::transmute(&1) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -145,7 +145,7 @@ LL | const BAD_ENUM_PTR: Enum = unsafe { mem::transmute(&1) };
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/ub-enum.rs:30:1
+  --> $DIR/ub-enum.rs:31:1
    |
 LL | const BAD_ENUM_WRAPPED: Wrap<Enum> = unsafe { mem::transmute(&1) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -158,7 +158,7 @@ LL | const BAD_ENUM_WRAPPED: Wrap<Enum> = unsafe { mem::transmute(&1) };
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/ub-enum.rs:45:1
+  --> $DIR/ub-enum.rs:46:1
    |
 LL | const BAD_ENUM2_PTR: Enum2 = unsafe { mem::transmute(&0) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -171,7 +171,7 @@ LL | const BAD_ENUM2_PTR: Enum2 = unsafe { mem::transmute(&0) };
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/ub-enum.rs:49:1
+  --> $DIR/ub-enum.rs:50:1
    |
 LL | const BAD_ENUM2_WRAPPED: Wrap<Enum2> = unsafe { mem::transmute(&0) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -184,7 +184,7 @@ LL | const BAD_ENUM2_WRAPPED: Wrap<Enum2> = unsafe { mem::transmute(&0) };
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/ub-enum.rs:64:1
+  --> $DIR/ub-enum.rs:65:1
    |
 LL | const BAD_ENUM2_OPTION_PTR: Option<Enum2> = unsafe { mem::transmute(&0) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes

diff --git a/src/test/ui/consts/const-eval/ub-enum.rs b/src/test/ui/consts/const-eval/ub-enum.rs
@@ -1,5 +1,6 @@
 // stderr-per-bitwidth
 #![feature(never_type)]
+#![allow(invalid_value)]
 
 use std::mem;
 

diff --git a/src/test/ui/lint/invalid_value.rs b/src/test/ui/lint/invalid_value.rs
@@ -41,7 +41,7 @@ enum OneFruitNonZero {
 
 enum TwoUninhabited {
     A(!),
-    B(!),
+    B(Void),
 }
 
 #[allow(unused)]