Avoid follow-up errors and ICEs after missing lifetime errors on data structures

Author: oli-obk

compiler/rustc_infer/src/infer/mod.rs

@@ -1273,6 +1273,9 @@ impl<'tcx> InferCtxt<'tcx> {
     where
         T: TypeFoldable<TyCtxt<'tcx>>,
     {
+        if let Err(guar) = value.error_reported() {
+            self.set_tainted_by_errors(guar);
+        }
         if !value.has_non_region_infer() {
             return value;
         }

tests/crashes/124083.rs

@@ -30,31 +30,7 @@ help: add `#![feature(generic_arg_infer)]` to the crate attributes to enable
 LL + #![feature(generic_arg_infer)]
    |
 
-error[E0284]: type annotations needed
-  --> $DIR/issue-62878.rs:10:5
-   |
-LL |     foo::<_, { [1] }>();
-   |     ^^^^^^^^^^^^^^^^^ cannot infer the value of the const parameter `N` declared on the function `foo`
-   |
-note: required by a const generic parameter in `foo`
-  --> $DIR/issue-62878.rs:5:8
-   |
-LL | fn foo<const N: usize, const A: [u8; N]>() {}
-   |        ^^^^^^^^^^^^^^ required by this const generic parameter in `foo`
-
-error[E0284]: type annotations needed
-  --> $DIR/issue-62878.rs:10:5
-   |
-LL |     foo::<_, { [1] }>();
-   |     ^^^^^^^^^^^^^^^^^ cannot infer the value of the const parameter `A` declared on the function `foo`
-   |
-note: required by a const generic parameter in `foo`
-  --> $DIR/issue-62878.rs:5:24
-   |
-LL | fn foo<const N: usize, const A: [u8; N]>() {}
-   |                        ^^^^^^^^^^^^^^^^ required by this const generic parameter in `foo`
-
-error: aborting due to 5 previous errors
+error: aborting due to 3 previous errors
 
-Some errors have detailed explanations: E0284, E0747, E0770.
-For more information about an error, try `rustc --explain E0284`.
+Some errors have detailed explanations: E0747, E0770.
+For more information about an error, try `rustc --explain E0747`.

tests/crashes/124262.rs

@@ -9,6 +9,4 @@ fn foo<const N: usize, const A: [u8; N]>() {}
 fn main() {
     foo::<_, { [1] }>();
     //[min]~^ ERROR: type provided when a constant was expected
-    //[min]~| ERROR type annotations needed
-    //[min]~| ERROR type annotations needed
 }

tests/crashes/125155.rs

@@ -7,25 +7,13 @@ LL |     pub fn call_me<Args: Sized, const IDX: usize, const FN: unsafe extern "
    = note: type parameters may not be used in the type of const parameters
 
 error[E0770]: the type of const parameters must not depend on other generic parameters
-  --> $DIR/issue-71381.rs:24:40
+  --> $DIR/issue-71381.rs:23:40
    |
 LL |         const FN: unsafe extern "C" fn(Args),
    |                                        ^^^^ the type must not depend on the parameter `Args`
    |
    = note: type parameters may not be used in the type of const parameters
 
-error[E0594]: cannot assign to `self.0`, which is behind a `&` reference
-  --> $DIR/issue-71381.rs:17:9
-   |
-LL |         self.0 = Self::trampiline::<Args, IDX, FN> as _
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `self` is a `&` reference, so the data it refers to cannot be written
-   |
-help: consider changing this to be a mutable reference
-   |
-LL |     pub fn call_me<Args: Sized, const IDX: usize, const FN: unsafe extern "C" fn(Args)>(&mut self) {
-   |                                                                                         ~~~~~~~~~
-
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0594, E0770.
-For more information about an error, try `rustc --explain E0594`.
+For more information about this error, try `rustc --explain E0770`.

tests/crashes/125888.rs

@@ -7,7 +7,7 @@ LL |     pub fn call_me<Args: Sized, const IDX: usize, const FN: unsafe extern "
    = note: type parameters may not be used in the type of const parameters
 
 error[E0770]: the type of const parameters must not depend on other generic parameters
-  --> $DIR/issue-71381.rs:24:40
+  --> $DIR/issue-71381.rs:23:40
    |
 LL |         const FN: unsafe extern "C" fn(Args),
    |                                        ^^^^ the type must not depend on the parameter `Args`
@@ -23,25 +23,13 @@ LL |     pub fn call_me<Args: Sized, const IDX: usize, const FN: unsafe extern "
    = note: the only supported types are integers, `bool` and `char`
 
 error: using function pointers as const generic parameters is forbidden
-  --> $DIR/issue-71381.rs:24:19
+  --> $DIR/issue-71381.rs:23:19
    |
 LL |         const FN: unsafe extern "C" fn(Args),
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: the only supported types are integers, `bool` and `char`
 
-error[E0594]: cannot assign to `self.0`, which is behind a `&` reference
-  --> $DIR/issue-71381.rs:17:9
-   |
-LL |         self.0 = Self::trampiline::<Args, IDX, FN> as _
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `self` is a `&` reference, so the data it refers to cannot be written
-   |
-help: consider changing this to be a mutable reference
-   |
-LL |     pub fn call_me<Args: Sized, const IDX: usize, const FN: unsafe extern "C" fn(Args)>(&mut self) {
-   |                                                                                         ~~~~~~~~~
-
-error: aborting due to 5 previous errors
+error: aborting due to 4 previous errors
 
-Some errors have detailed explanations: E0594, E0770.
-For more information about an error, try `rustc --explain E0594`.
+For more information about this error, try `rustc --explain E0770`.

tests/crashes/125992.rs

@@ -15,7 +15,6 @@ impl Test {
         //~^ ERROR: the type of const parameters must not depend on other generic parameters
         //[min]~^^ ERROR: using function pointers as const generic parameters is forbidden
         self.0 = Self::trampiline::<Args, IDX, FN> as _
-        //~^ ERROR: cannot assign to `self.0`
     }
 
     unsafe extern "C" fn trampiline<

tests/crashes/126648.rs

@@ -16,7 +16,6 @@ fn make_marker() -> impl Marker<gimme_a_const!(marker)> {
   //~| ERROR: type provided when a constant was expected
   Example::<gimme_a_const!(marker)>
   //~^ ERROR: type provided when a constant was expected
-  //~| ERROR type annotations needed
 }
 
 fn from_marker(_: impl Marker<{

tests/crashes/126666.rs

@@ -1,5 +1,5 @@
 error: expected type, found `{`
-  --> $DIR/macro-fail.rs:31:27
+  --> $DIR/macro-fail.rs:30:27
    |
 LL | fn make_marker() -> impl Marker<gimme_a_const!(marker)> {
    |                                 ----------------------
@@ -13,7 +13,7 @@ LL |       ($rusty: ident) => {{ let $rusty = 3; *&$rusty }}
    = note: this error originates in the macro `gimme_a_const` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: expected type, found `{`
-  --> $DIR/macro-fail.rs:31:27
+  --> $DIR/macro-fail.rs:30:27
    |
 LL |   Example::<gimme_a_const!(marker)>
    |             ----------------------
@@ -41,7 +41,7 @@ LL |   let _fail = Example::<external_macro!()>;
    = note: this error originates in the macro `external_macro` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: unexpected end of macro invocation
-  --> $DIR/macro-fail.rs:42:25
+  --> $DIR/macro-fail.rs:41:25
    |
 LL |     macro_rules! gimme_a_const {
    |     -------------------------- when calling this macro
@@ -50,7 +50,7 @@ LL |   let _fail = Example::<gimme_a_const!()>;
    |                         ^^^^^^^^^^^^^^^^ missing tokens in macro arguments
    |
 note: while trying to match meta-variable `$rusty:ident`
-  --> $DIR/macro-fail.rs:31:8
+  --> $DIR/macro-fail.rs:30:8
    |
 LL |       ($rusty: ident) => {{ let $rusty = 3; *&$rusty }}
    |        ^^^^^^^^^^^^^
@@ -75,32 +75,20 @@ error[E0747]: type provided when a constant was expected
 LL |   Example::<gimme_a_const!(marker)>
    |             ^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0284]: type annotations needed
-  --> $DIR/macro-fail.rs:17:3
-   |
-LL |   Example::<gimme_a_const!(marker)>
-   |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer the value of the const parameter `N` declared on the struct `Example`
-   |
-note: required by a const generic parameter in `Example`
-  --> $DIR/macro-fail.rs:1:16
-   |
-LL | struct Example<const N: usize>;
-   |                ^^^^^^^^^^^^^^ required by this const generic parameter in `Example`
-
 error[E0747]: type provided when a constant was expected
-  --> $DIR/macro-fail.rs:38:25
+  --> $DIR/macro-fail.rs:37:25
    |
 LL |   let _fail = Example::<external_macro!()>;
    |                         ^^^^^^^^^^^^^^^^^
 
 error[E0747]: type provided when a constant was expected
-  --> $DIR/macro-fail.rs:42:25
+  --> $DIR/macro-fail.rs:41:25
    |
 LL |   let _fail = Example::<gimme_a_const!()>;
    |                         ^^^^^^^^^^^^^^^^
 
 error[E0284]: type annotations needed for `Example<_>`
-  --> $DIR/macro-fail.rs:38:7
+  --> $DIR/macro-fail.rs:37:7
    |
 LL |   let _fail = Example::<external_macro!()>;
    |       ^^^^^   ---------------------------- type must be known at this point
@@ -116,7 +104,7 @@ LL |   let _fail: Example<N> = Example::<external_macro!()>;
    |            ++++++++++++
 
 error[E0284]: type annotations needed for `Example<_>`
-  --> $DIR/macro-fail.rs:42:7
+  --> $DIR/macro-fail.rs:41:7
    |
 LL |   let _fail = Example::<gimme_a_const!()>;
    |       ^^^^^   --------------------------- type must be known at this point
@@ -131,7 +119,7 @@ help: consider giving `_fail` an explicit type, where the value of const paramet
 LL |   let _fail: Example<N> = Example::<gimme_a_const!()>;
    |            ++++++++++++
 
-error: aborting due to 12 previous errors
+error: aborting due to 11 previous errors
 
 Some errors have detailed explanations: E0284, E0747.
 For more information about an error, try `rustc --explain E0284`.

tests/ui/const-generics/issues/issue-62878.min.stderr

@@ -15,7 +15,6 @@ fn gather_from_file(dir_entry: &foo::MissingItem) -> impl Iterator<Item = Lint>
 
 fn lint_files() -> impl Iterator<Item = foo::MissingItem> {
     //~^ ERROR: failed to resolve
-    //~| ERROR: `()` is not an iterator
     unimplemented!()
 }
 

tests/ui/const-generics/issues/issue-62878.rs

@@ -1,11 +1,3 @@
-error[E0277]: `()` is not an iterator
-  --> $DIR/issue-72911.rs:16:20
-   |
-LL | fn lint_files() -> impl Iterator<Item = foo::MissingItem> {
-   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `()` is not an iterator
-   |
-   = help: the trait `Iterator` is not implemented for `()`
-
 error[E0433]: failed to resolve: use of undeclared crate or module `foo`
   --> $DIR/issue-72911.rs:11:33
    |
@@ -18,7 +10,6 @@ error[E0433]: failed to resolve: use of undeclared crate or module `foo`
 LL | fn lint_files() -> impl Iterator<Item = foo::MissingItem> {
    |                                         ^^^ use of undeclared crate or module `foo`
 
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0277, E0433.
-For more information about an error, try `rustc --explain E0277`.
+For more information about this error, try `rustc --explain E0433`.

tests/ui/const-generics/issues/issue-71381.full.stderr

@@ -9,7 +9,6 @@ impl<T, S: Iterator<Item = T>> Iterator for ChunkingIterator<T, S> {
     type Item = IteratorChunk<T, S>; //~ ERROR missing lifetime
 
     fn next(&mut self) -> Option<IteratorChunk<T, S>> {
-        //~^ ERROR `impl` item signature doesn't match `trait` item signature
         todo!()
     }
 }

tests/ui/const-generics/issues/issue-71381.min.stderr

@@ -9,20 +9,6 @@ help: consider introducing a named lifetime parameter
 LL |     type Item<'a> = IteratorChunk<'a, T, S>;
    |              ++++                 +++
 
-error: `impl` item signature doesn't match `trait` item signature
-  --> $DIR/issue-74918-missing-lifetime.rs:11:5
-   |
-LL |     fn next(&mut self) -> Option<IteratorChunk<T, S>> {
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ found `fn(&'1 mut ChunkingIterator<T, S>) -> Option<IteratorChunk<'1, T, S>>`
-  --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
-   |
-   = note: expected `fn(&'1 mut ChunkingIterator<T, S>) -> Option<IteratorChunk<'2, T, S>>`
-   |
-   = note: expected signature `fn(&'1 mut ChunkingIterator<T, S>) -> Option<IteratorChunk<'2, T, S>>`
-              found signature `fn(&'1 mut ChunkingIterator<T, S>) -> Option<IteratorChunk<'1, T, S>>`
-   = help: the lifetime requirements from the `impl` do not correspond to the requirements in the `trait`
-   = help: verify the lifetime relationships in the `trait` and `impl` between the `self` argument, the other inputs and its output
-
-error: aborting due to 2 previous errors
+error: aborting due to 1 previous error
 
 For more information about this error, try `rustc --explain E0106`.

tests/ui/const-generics/issues/issue-71381.rs

@@ -0,0 +1,9 @@
+//! This test checks that we taint typeck results when there are
+//! error lifetimes, even though typeck doesn't actually care about lifetimes.
+
+struct Slice(&'reborrow [&'static [u8]]);
+//~^ ERROR undeclared lifetime
+
+static MAP: Slice = Slice(&[b"" as &'static [u8]]);
+
+fn main() {}