rust-lang · politikl · Nov 9, 2025
diff --git a/compiler/rustc_error_codes/src/error_codes/E0412.md b/compiler/rustc_error_codes/src/error_codes/E0412.md
@@ -1,8 +1,12 @@
+#### Note: this error code is no longer emitted by the compiler.
+
+This error has been merged into E0425.
+
 A used type name is not in scope.
 
 Erroneous code examples:
 
-```compile_fail,E0412
+```compile_fail,E0425
 impl Something {} // error: type name `Something` is not in scope
 
 // or:
@@ -42,7 +46,7 @@ module. To fix this, you can follow the suggestion and use File directly or
 `use super::File;` which will import the types from the parent namespace. An
 example that causes this error is below:
 
-```compile_fail,E0412
+```compile_fail,E0425
 use std::fs::File;
 
 mod foo {

diff --git a/compiler/rustc_error_codes/src/error_codes/E0425.md b/compiler/rustc_error_codes/src/error_codes/E0425.md
@@ -17,6 +17,14 @@ trait Foo {
 // or:
 
 let x = unknown_variable;  // error: unresolved name `unknown_variable`
+
+// or:
+
+impl Something {} // error: type name `Something` is not in scope
+
+// or:
+
+fn foo(x: T) {} // error: type name `T` is not in scope
 ```
 
 Please verify that the name wasn't misspelled and ensure that the
@@ -45,6 +53,18 @@ let unknown_variable = 12u32;
 let x = unknown_variable; // ok!
 ```
 
+Or for types:
+
+```
+struct Something;
+
+impl Something {} // ok!
+
+// or:
+
+fn foo<T>(x: T) {} // ok!
+```
+
 If the item is not defined in the current module, it must be imported using a
 `use` statement, like so:
 

diff --git a/compiler/rustc_error_codes/src/lib.rs b/compiler/rustc_error_codes/src/lib.rs
@@ -607,7 +607,7 @@ E0805: 0805,
 //  E0246, // invalid recursive type
 //  E0247,
 //  E0248, // value used as a type, now reported earlier during resolution
-//         // as E0412
+//         // as E0425
 //  E0249,
 //  E0257,
 //  E0258,

diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
@@ -622,7 +622,7 @@ impl PathSource<'_, '_, '_> {
             (PathSource::Trait(_), true) => E0404,
             (PathSource::Trait(_), false) => E0405,
             (PathSource::Type | PathSource::DefineOpaques, true) => E0573,
-            (PathSource::Type | PathSource::DefineOpaques, false) => E0412,
+            (PathSource::Type | PathSource::DefineOpaques, false) => E0425,
             (PathSource::Struct(_), true) => E0574,
             (PathSource::Struct(_), false) => E0422,
             (PathSource::Expr(..), true) | (PathSource::Delegation, true) => E0423,
@@ -3161,7 +3161,7 @@ impl<'a, 'ast, 'ra, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
         result
     }
 
-    /// When evaluating a `trait` use its associated types' idents for suggestions in E0412.
+    /// When evaluating a `trait` use its associated types' idents for suggestions in E0425.
     fn resolve_trait_items(&mut self, trait_items: &'ast [Box<AssocItem>]) {
         let trait_assoc_items =
             replace(&mut self.diag_metadata.current_trait_assoc_items, Some(trait_items));
@@ -4362,15 +4362,15 @@ impl<'a, 'ast, 'ra, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
 
                 // There are two different error messages user might receive at
                 // this point:
-                // - E0412 cannot find type `{}` in this scope
+                // - E0425 cannot find value `{}` in this scope
                 // - E0433 failed to resolve: use of undeclared type or module `{}`
                 //
-                // The first one is emitted for paths in type-position, and the
-                // latter one - for paths in expression-position.
+                // The first one is emitted for unresolved names, and the
+                // latter one - for paths in use statements.
                 //
                 // Thus (since we're in expression-position at this point), not to
                 // confuse the user, we want to keep the *message* from E0433 (so
-                // `parent_err`), but we want *hints* from E0412 (so `err`).
+                // `parent_err`), but we want *hints* from E0425 (so `err`).
                 //
                 // And that's what happens below - we're just mixing both messages
                 // into a single one.

diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs
@@ -705,7 +705,7 @@ impl<'ast, 'ra, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
             if !enum_candidates.is_empty() {
                 enum_candidates.sort();
 
-                // Contextualize for E0412 "cannot find type", but don't belabor the point
+                // Contextualize for E0425 "cannot find value", but don't belabor the point
                 // (that it's a variant) for E0573 "expected type, found variant".
                 let preamble = if res.is_none() {
                     let others = match enum_candidates.len() {
@@ -1127,7 +1127,7 @@ impl<'ast, 'ra, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
                 }
 
                 self.suggest_ident_hidden_by_hygiene(err, path, span);
-            } else if err_code == E0412 {
+            } else if err_code == E0425 {
                 if let Some(correct) = Self::likely_rust_type(path) {
                     err.span_suggestion(
                         span,

diff --git a/tests/rustdoc-ui/impl-fn-nesting.stderr b/tests/rustdoc-ui/impl-fn-nesting.stderr
@@ -10,7 +10,7 @@ error[E0405]: cannot find trait `UnknownBound` in this scope
 LL | pub fn f<B: UnknownBound>(a: UnknownType, b: B) {
    |             ^^^^^^^^^^^^ not found in this scope
 
-error[E0412]: cannot find type `UnknownType` in this scope
+error[E0425]: cannot find type `UnknownType` in this scope
   --> $DIR/impl-fn-nesting.rs:11:30
    |
 LL | pub fn f<B: UnknownBound>(a: UnknownType, b: B) {
@@ -34,7 +34,7 @@ error[E0405]: cannot find trait `UnknownBound` in this scope
 LL |     impl<T: UnknownBound> UnknownTrait for T {}
    |             ^^^^^^^^^^^^ not found in this scope
 
-error[E0412]: cannot find type `UnknownType` in this scope
+error[E0425]: cannot find type `UnknownType` in this scope
   --> $DIR/impl-fn-nesting.rs:18:25
    |
 LL |     impl ValidTrait for UnknownType {}
@@ -46,19 +46,19 @@ error[E0405]: cannot find trait `UnknownBound` in this scope
 LL |     impl ValidTrait for ValidType where ValidTrait: UnknownBound {}
    |                                                     ^^^^^^^^^^^^ not found in this scope
 
-error[E0412]: cannot find type `UnknownType` in this scope
+error[E0425]: cannot find type `UnknownType` in this scope
   --> $DIR/impl-fn-nesting.rs:25:21
    |
 LL |         type Item = UnknownType;
    |                     ^^^^^^^^^^^ not found in this scope
 
-error[E0412]: cannot find type `UnknownType` in this scope
+error[E0425]: cannot find type `UnknownType` in this scope
   --> $DIR/impl-fn-nesting.rs:44:37
    |
 LL |             pub fn doubly_nested(c: UnknownType) {
    |                                     ^^^^^^^^^^^ not found in this scope
 
 error: aborting due to 10 previous errors
 
-Some errors have detailed explanations: E0405, E0412.
+Some errors have detailed explanations: E0405, E0425.
 For more information about an error, try `rustc --explain E0405`.
diff --git a/tests/ui/annotate-snippet/missing-type.stderr b/tests/ui/annotate-snippet/missing-type.stderr
@@ -1,4 +1,4 @@
-error[E0412]: cannot find type `Iter` in this scope
+error[E0425]: cannot find type `Iter` in this scope
   --> $DIR/missing-type.rs:4:12
    |
 LL |     let x: Iter;
@@ -18,4 +18,4 @@ LL + use std::collections::hash_map::Iter;
 
 error: aborting due to 1 previous error
 
-For more information about this error, try `rustc --explain E0412`.
+For more information about this error, try `rustc --explain E0425`.
diff --git a/tests/ui/argument-suggestions/extern-fn-arg-names.stderr b/tests/ui/argument-suggestions/extern-fn-arg-names.stderr
@@ -1,4 +1,4 @@
-error[E0412]: cannot find type `err` in this scope
+error[E0425]: cannot find type `err` in this scope
   --> $DIR/extern-fn-arg-names.rs:2:29
    |
 LL |     fn dstfn(src: i32, dst: err);
@@ -22,5 +22,5 @@ LL |     dstfn(1, /* dst */);
 
 error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0061, E0412.
+Some errors have detailed explanations: E0061, E0425.
 For more information about an error, try `rustc --explain E0061`.
diff --git a/tests/ui/argument-suggestions/issue-109831.rs b/tests/ui/argument-suggestions/issue-109831.rs
@@ -1,7 +1,7 @@
 struct A;
 struct B;
 
-fn f(b1: B, b2: B, a2: C) {} //~ ERROR E0412
+fn f(b1: B, b2: B, a2: C) {} //~ ERROR E0425
 
 fn main() {
     f(A, A, B, C); //~ ERROR E0425

diff --git a/tests/ui/argument-suggestions/issue-109831.stderr b/tests/ui/argument-suggestions/issue-109831.stderr
@@ -1,4 +1,4 @@
-error[E0412]: cannot find type `C` in this scope
+error[E0425]: cannot find type `C` in this scope
   --> $DIR/issue-109831.rs:4:24
    |
 LL | struct A;
@@ -48,5 +48,5 @@ LL +     f(/* B */, /* B */, B);
 
 error: aborting due to 3 previous errors
 
-Some errors have detailed explanations: E0061, E0412, E0425.
+Some errors have detailed explanations: E0061, E0425, E0425.
 For more information about an error, try `rustc --explain E0061`.
diff --git a/tests/ui/asm/issue-113788.rs b/tests/ui/asm/issue-113788.rs
@@ -2,6 +2,6 @@
 //@ needs-asm-support
 //@ only-x86_64
 fn main() {
-    let peb: *const PEB; //~ ERROR cannot find type `PEB` in this scope [E0412]
+    let peb: *const PEB; //~ ERROR cannot find type `PEB` in this scope [E0425]
     unsafe { std::arch::asm!("mov {0}, fs:[0x30]", out(reg) peb); }
 }
diff --git a/tests/ui/asm/issue-113788.stderr b/tests/ui/asm/issue-113788.stderr
@@ -1,9 +1,9 @@
-error[E0412]: cannot find type `PEB` in this scope
+error[E0425]: cannot find type `PEB` in this scope
   --> $DIR/issue-113788.rs:5:21
    |
 LL |     let peb: *const PEB;
    |                     ^^^ not found in this scope
 
 error: aborting due to 1 previous error
 
-For more information about this error, try `rustc --explain E0412`.
+For more information about this error, try `rustc --explain E0425`.
diff --git a/tests/ui/associated-consts/issue-93835.stderr b/tests/ui/associated-consts/issue-93835.stderr
@@ -4,7 +4,7 @@ error[E0425]: cannot find value `p` in this scope
 LL |     type_ascribe!(p, a<p:p<e=6>>);
    |                   ^ not found in this scope
 
-error[E0412]: cannot find type `a` in this scope
+error[E0425]: cannot find type `a` in this scope
   --> $DIR/issue-93835.rs:4:22
    |
 LL |     type_ascribe!(p, a<p:p<e=6>>);
@@ -39,5 +39,5 @@ LL |     type_ascribe!(p, a<p:p<e=6>>);
 
 error: aborting due to 5 previous errors
 
-Some errors have detailed explanations: E0405, E0412, E0425, E0658.
+Some errors have detailed explanations: E0405, E0425, E0425, E0658.
 For more information about an error, try `rustc --explain E0405`.
diff --git a/tests/ui/associated-type-bounds/return-type-notation/not-a-method.stderr b/tests/ui/associated-type-bounds/return-type-notation/not-a-method.stderr
@@ -16,7 +16,7 @@ error[E0576]: cannot find function `method` in this scope
 LL |     method(..): Send,
    |     ^^^^^^ not found in this scope
 
-error[E0412]: cannot find type `method` in this scope
+error[E0425]: cannot find type `method` in this scope
   --> $DIR/not-a-method.rs:36:5
    |
 LL |     method(): Send,
@@ -36,5 +36,5 @@ LL |     method(..): Send,
 
 error: aborting due to 6 previous errors
 
-Some errors have detailed explanations: E0412, E0573, E0575, E0576.
-For more information about an error, try `rustc --explain E0412`.
+Some errors have detailed explanations: E0425, E0573, E0575, E0576.
+For more information about an error, try `rustc --explain E0425`.
diff --git a/tests/ui/associated-types/associated-types-eq-1.stderr b/tests/ui/associated-types/associated-types-eq-1.stderr
@@ -1,4 +1,4 @@
-error[E0412]: cannot find type `A` in this scope
+error[E0425]: cannot find type `A` in this scope
   --> $DIR/associated-types-eq-1.rs:10:12
    |
 LL | fn foo2<I: Foo>(x: I) {
@@ -18,4 +18,4 @@ LL | fn foo2<I: Foo, A>(x: I) {
 
 error: aborting due to 1 previous error
 
-For more information about this error, try `rustc --explain E0412`.
+For more information about this error, try `rustc --explain E0425`.
diff --git a/tests/ui/async-await/in-trait/return-not-existing-pair.rs b/tests/ui/async-await/in-trait/return-not-existing-pair.rs
@@ -3,7 +3,7 @@
 
 trait MyTrait<'a, 'b, T> {
     async fn foo(&'a self, key: &'b T) -> (&'a ConnImpl, &'b T);
-    //~^ ERROR: cannot find type `ConnImpl` in this scope [E0412]
+    //~^ ERROR: cannot find type `ConnImpl` in this scope [E0425]
 }
 
 impl<'a, 'b, T, U> MyTrait<T> for U {

diff --git a/tests/ui/async-await/in-trait/return-not-existing-pair.stderr b/tests/ui/async-await/in-trait/return-not-existing-pair.stderr
@@ -9,7 +9,7 @@ help: indicate the anonymous lifetimes
 LL | impl<'a, 'b, T, U> MyTrait<'_, '_, T> for U {
    |                            +++++++
 
-error[E0412]: cannot find type `ConnImpl` in this scope
+error[E0425]: cannot find type `ConnImpl` in this scope
   --> $DIR/return-not-existing-pair.rs:5:48
    |
 LL |     async fn foo(&'a self, key: &'b T) -> (&'a ConnImpl, &'b T);
@@ -26,5 +26,5 @@ LL |     async fn foo(_: T) -> (&'a U, &'b T) {}
 
 error: aborting due to 3 previous errors
 
-Some errors have detailed explanations: E0308, E0412, E0726.
+Some errors have detailed explanations: E0308, E0425, E0726.
 For more information about an error, try `rustc --explain E0308`.
diff --git a/tests/ui/async-await/in-trait/return-not-existing-type-wrapping-rpitit.rs b/tests/ui/async-await/in-trait/return-not-existing-type-wrapping-rpitit.rs
@@ -5,7 +5,7 @@ struct Wrapper<T>(T);
 
 trait Foo {
     fn bar() -> Wrapper<Missing<impl Sized>>;
-    //~^ ERROR: cannot find type `Missing` in this scope [E0412]
+    //~^ ERROR: cannot find type `Missing` in this scope [E0425]
 }
 
 impl Foo for () {

diff --git a/tests/ui/async-await/in-trait/return-not-existing-type-wrapping-rpitit.stderr b/tests/ui/async-await/in-trait/return-not-existing-type-wrapping-rpitit.stderr
@@ -1,9 +1,9 @@
-error[E0412]: cannot find type `Missing` in this scope
+error[E0425]: cannot find type `Missing` in this scope
   --> $DIR/return-not-existing-type-wrapping-rpitit.rs:7:25
    |
 LL |     fn bar() -> Wrapper<Missing<impl Sized>>;
    |                         ^^^^^^^ not found in this scope
 
 error: aborting due to 1 previous error
 
-For more information about this error, try `rustc --explain E0412`.
+For more information about this error, try `rustc --explain E0425`.
diff --git a/tests/ui/async-await/issue-72590-type-error-sized.stderr b/tests/ui/async-await/issue-72590-type-error-sized.stderr
@@ -1,10 +1,10 @@
-error[E0412]: cannot find type `Nonexistent` in this scope
+error[E0425]: cannot find type `Nonexistent` in this scope
   --> $DIR/issue-72590-type-error-sized.rs:6:10
    |
 LL |     foo: Nonexistent,
    |          ^^^^^^^^^^^ not found in this scope
 
-error[E0412]: cannot find type `Missing` in this scope
+error[E0425]: cannot find type `Missing` in this scope
   --> $DIR/issue-72590-type-error-sized.rs:11:11
    |
 LL |     test: Missing
@@ -30,5 +30,5 @@ LL |     async fn frob(&self) {}
 
 error: aborting due to 3 previous errors
 
-Some errors have detailed explanations: E0277, E0412.
+Some errors have detailed explanations: E0277, E0425.
 For more information about an error, try `rustc --explain E0277`.
diff --git a/tests/ui/async-await/unconstrained-lifetimes.stderr b/tests/ui/async-await/unconstrained-lifetimes.stderr
@@ -1,9 +1,9 @@
-error[E0412]: cannot find type `Missing` in this scope
+error[E0425]: cannot find type `Missing` in this scope
   --> $DIR/unconstrained-lifetimes.rs:6:17
    |
 LL | async fn foo(_: Missing<'_>) {}
    |                 ^^^^^^^ not found in this scope
 
 error: aborting due to 1 previous error
 
-For more information about this error, try `rustc --explain E0412`.
+For more information about this error, try `rustc --explain E0425`.
diff --git a/tests/ui/borrowck/bad-drop-side-effects.stderr b/tests/ui/borrowck/bad-drop-side-effects.stderr
@@ -1,9 +1,9 @@
-error[E0412]: cannot find type `Missing` in this scope
+error[E0425]: cannot find type `Missing` in this scope
   --> $DIR/bad-drop-side-effects.rs:7:16
    |
 LL | impl<U> B for &Missing {
    |                ^^^^^^^ not found in this scope
 
 error: aborting due to 1 previous error
 
-For more information about this error, try `rustc --explain E0412`.
+For more information about this error, try `rustc --explain E0425`.
diff --git a/tests/ui/c-variadic/issue-86053-1.stderr b/tests/ui/c-variadic/issue-86053-1.stderr
@@ -54,7 +54,7 @@ LL |     self , ... ,   self ,   self , ... ) where F : FnOnce ( & 'a & 'b usize
    |
    = help: only `extern "C"` and `extern "C-unwind"` functions may have a C variable argument list
 
-error[E0412]: cannot find type `F` in this scope
+error[E0425]: cannot find type `F` in this scope
   --> $DIR/issue-86053-1.rs:11:48
    |
 LL |     self , ... ,   self ,   self , ... ) where F : FnOnce ( & 'a & 'b usize ) {
@@ -74,4 +74,4 @@ LL | fn ordering4 < 'a , 'b, F     > ( a :            ,   self , self ,   self ,
 
 error: aborting due to 10 previous errors
 
-For more information about this error, try `rustc --explain E0412`.
+For more information about this error, try `rustc --explain E0425`.
diff --git a/tests/ui/cast/casts-issue-46365.stderr b/tests/ui/cast/casts-issue-46365.stderr
@@ -1,9 +1,9 @@
-error[E0412]: cannot find type `Ipsum` in this scope
+error[E0425]: cannot find type `Ipsum` in this scope
   --> $DIR/casts-issue-46365.rs:2:12
    |
 LL |     ipsum: Ipsum
    |            ^^^^^ not found in this scope
 
 error: aborting due to 1 previous error
 
-For more information about this error, try `rustc --explain E0412`.
+For more information about this error, try `rustc --explain E0425`.