From c9deaf6aaa8e389e11e39abb9aca77e6340d176e Mon Sep 17 00:00:00 2001
From: Kivooeo <Kivooeo123@gmail.com>
Date: Wed, 23 Apr 2025 15:58:50 +0500
Subject: [PATCH] fix for issue 135412

---
 compiler/rustc_hir_typeck/src/cast.rs         | 25 ++++++++++++----
 tests/ui/coercion/issue-73886.stderr          |  7 ++++-
 .../coercion/non-primitive-cast-135412.fixed  | 10 +++++++
 .../ui/coercion/non-primitive-cast-135412.rs  | 10 +++++++
 .../coercion/non-primitive-cast-135412.stderr | 29 +++++++++++++++++++
 5 files changed, 74 insertions(+), 7 deletions(-)
 create mode 100644 tests/ui/coercion/non-primitive-cast-135412.fixed
 create mode 100644 tests/ui/coercion/non-primitive-cast-135412.rs
 create mode 100644 tests/ui/coercion/non-primitive-cast-135412.stderr

diff --git a/compiler/rustc_hir_typeck/src/cast.rs b/compiler/rustc_hir_typeck/src/cast.rs
index b19d9efe2c6f5..caf36ba47bd75 100644
--- a/compiler/rustc_hir_typeck/src/cast.rs
+++ b/compiler/rustc_hir_typeck/src/cast.rs
@@ -501,12 +501,25 @@ impl<'a, 'tcx> CastCheck<'tcx> {
                             .must_apply_modulo_regions()
                         {
                             label = false;
-                            err.span_suggestion(
-                                self.span,
-                                "consider using the `From` trait instead",
-                                format!("{}::from({})", self.cast_ty, snippet),
-                                Applicability::MaybeIncorrect,
-                            );
+                            if let ty::Adt(def, args) = self.cast_ty.kind() {
+                                err.span_suggestion_verbose(
+                                    self.span,
+                                    "consider using the `From` trait instead",
+                                    format!(
+                                        "{}::from({})",
+                                        fcx.tcx.value_path_str_with_args(def.did(), args),
+                                        snippet
+                                    ),
+                                    Applicability::MaybeIncorrect,
+                                );
+                            } else {
+                                err.span_suggestion(
+                                    self.span,
+                                    "consider using the `From` trait instead",
+                                    format!("{}::from({})", self.cast_ty, snippet),
+                                    Applicability::MaybeIncorrect,
+                                );
+                            };
                         }
                     }
 
diff --git a/tests/ui/coercion/issue-73886.stderr b/tests/ui/coercion/issue-73886.stderr
index a6f8ba65ab51a..0d4c90017cf11 100644
--- a/tests/ui/coercion/issue-73886.stderr
+++ b/tests/ui/coercion/issue-73886.stderr
@@ -8,9 +8,14 @@ error[E0605]: non-primitive cast: `u32` as `Option<_>`
   --> $DIR/issue-73886.rs:4:13
    |
 LL |     let _ = 7u32 as Option<_>;
-   |             ^^^^^^^^^^^^^^^^^ help: consider using the `From` trait instead: `Option<_>::from(7u32)`
+   |             ^^^^^^^^^^^^^^^^^
    |
    = note: an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
+help: consider using the `From` trait instead
+   |
+LL -     let _ = 7u32 as Option<_>;
+LL +     let _ = Option::<_>::from(7u32);
+   |
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/coercion/non-primitive-cast-135412.fixed b/tests/ui/coercion/non-primitive-cast-135412.fixed
new file mode 100644
index 0000000000000..5cadc9368d52e
--- /dev/null
+++ b/tests/ui/coercion/non-primitive-cast-135412.fixed
@@ -0,0 +1,10 @@
+//@ run-rustfix
+
+use std::sync::Arc;
+
+fn main() {
+    let _ = Option::<_>::from(7u32);
+    //~^ ERROR non-primitive cast: `u32` as `Option<_>`
+    let _ = Arc::<str>::from("String");
+    //~^ ERROR non-primitive cast: `&'static str` as `Arc<str>`
+}
diff --git a/tests/ui/coercion/non-primitive-cast-135412.rs b/tests/ui/coercion/non-primitive-cast-135412.rs
new file mode 100644
index 0000000000000..67a3ef340d2f1
--- /dev/null
+++ b/tests/ui/coercion/non-primitive-cast-135412.rs
@@ -0,0 +1,10 @@
+//@ run-rustfix
+
+use std::sync::Arc;
+
+fn main() {
+    let _ = 7u32 as Option<_>;
+    //~^ ERROR non-primitive cast: `u32` as `Option<_>`
+    let _ = "String" as Arc<str>;
+    //~^ ERROR non-primitive cast: `&'static str` as `Arc<str>`
+}
diff --git a/tests/ui/coercion/non-primitive-cast-135412.stderr b/tests/ui/coercion/non-primitive-cast-135412.stderr
new file mode 100644
index 0000000000000..7e5861f83e9c1
--- /dev/null
+++ b/tests/ui/coercion/non-primitive-cast-135412.stderr
@@ -0,0 +1,29 @@
+error[E0605]: non-primitive cast: `u32` as `Option<_>`
+  --> $DIR/non-primitive-cast-135412.rs:6:13
+   |
+LL |     let _ = 7u32 as Option<_>;
+   |             ^^^^^^^^^^^^^^^^^
+   |
+   = note: an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
+help: consider using the `From` trait instead
+   |
+LL -     let _ = 7u32 as Option<_>;
+LL +     let _ = Option::<_>::from(7u32);
+   |
+
+error[E0605]: non-primitive cast: `&'static str` as `Arc<str>`
+  --> $DIR/non-primitive-cast-135412.rs:8:13
+   |
+LL |     let _ = "String" as Arc<str>;
+   |             ^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
+help: consider using the `From` trait instead
+   |
+LL -     let _ = "String" as Arc<str>;
+LL +     let _ = Arc::<str>::from("String");
+   |
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0605`.