Rollup merge of #140804 - bend-n:signed, r=lcnr

add signed ints to unn- transmutes to ensure feature parity

i forgot a few cases https://github.com/rust-lang/rust-clippy/pull/14703/#pullrequestreview-2824194994

adds

- char -> i32
-  i32 -> char
- float -> size ()
-  size -> float
-   i32 -> float
``@rustbot`` label L-unnecessary_transmutes

5 files changed, 86 insertions, 14 deletions

diff --git a/compiler/rustc_mir_transform/src/check_unnecessary_transmutes.rs b/compiler/rustc_mir_transform/src/check_unnecessary_transmutes.rs
index 4aff127908e..8da17a056e3 100644
--- a/compiler/rustc_mir_transform/src/check_unnecessary_transmutes.rs
+++ b/compiler/rustc_mir_transform/src/check_unnecessary_transmutes.rs
@@ -55,18 +55,45 @@ impl<'a, 'tcx> UnnecessaryTransmuteChecker<'a, 'tcx> {
             },
             // char → u32
             (Char, Uint(UintTy::U32)) => err(format!("u32::from({arg})")),
+            // char (→ u32) → i32
+            (Char, Int(IntTy::I32)) => err(format!("u32::from({arg}).cast_signed()")),
             // u32 → char
             (Uint(UintTy::U32), Char) => Error {
                 sugg: format!("char::from_u32_unchecked({arg})"),
                 help: Some("consider `char::from_u32(…).unwrap()`"),
                 span,
             },
+            // i32 → char
+            (Int(IntTy::I32), Char) => Error {
+                sugg: format!("char::from_u32_unchecked(i32::cast_unsigned({arg}))"),
+                help: Some("consider `char::from_u32(i32::cast_unsigned(…)).unwrap()`"),
+                span,
+            },
             // uNN → iNN
             (Uint(ty), Int(_)) => err(format!("{}::cast_signed({arg})", ty.name_str())),
             // iNN → uNN
             (Int(ty), Uint(_)) => err(format!("{}::cast_unsigned({arg})", ty.name_str())),
+            // fNN → xsize
+            (Float(ty), Uint(UintTy::Usize)) => {
+                err(format!("{}::to_bits({arg}) as usize", ty.name_str()))
+            }
+            (Float(ty), Int(IntTy::Isize)) => {
+                err(format!("{}::to_bits({arg}) as isize", ty.name_str()))
+            }
+            // fNN (→ uNN) → iNN
+            (Float(ty), Int(..)) => err(format!("{}::to_bits({arg}).cast_signed()", ty.name_str())),
             // fNN → uNN
             (Float(ty), Uint(..)) => err(format!("{}::to_bits({arg})", ty.name_str())),
+            // xsize → fNN
+            (Uint(UintTy::Usize) | Int(IntTy::Isize), Float(ty)) => {
+                err(format!("{}::from_bits({arg} as _)", ty.name_str(),))
+            }
+            // iNN (→ uNN) → fNN
+            (Int(int_ty), Float(ty)) => err(format!(
+                "{}::from_bits({}::cast_unsigned({arg}))",
+                ty.name_str(),
+                int_ty.name_str()
+            )),
             // uNN → fNN
             (Uint(_), Float(ty)) => err(format!("{}::from_bits({arg})", ty.name_str())),
             // bool → { x8 }
diff --git a/src/tools/miri/tests/pass/shims/x86/intrinsics-x86-sse2.rs b/src/tools/miri/tests/pass/shims/x86/intrinsics-x86-sse2.rs
index 7aaf9c2624f..731d8b57763 100644
--- a/src/tools/miri/tests/pass/shims/x86/intrinsics-x86-sse2.rs
+++ b/src/tools/miri/tests/pass/shims/x86/intrinsics-x86-sse2.rs
@@ -1,5 +1,6 @@
 // We're testing x86 target specific features
 //@only-target: x86_64 i686
+#![allow(unnecessary_transmutes)]
 
 #[cfg(target_arch = "x86")]
 use std::arch::x86::*;
diff --git a/tests/ui/transmute/unnecessary-transmutation.fixed b/tests/ui/transmute/unnecessary-transmutation.fixed
index 1a0df143cc5..bf7d769348a 100644
--- a/tests/ui/transmute/unnecessary-transmutation.fixed
+++ b/tests/ui/transmute/unnecessary-transmutation.fixed
@@ -49,6 +49,10 @@ fn main() {
         //~^ ERROR
         let y: char = char::from_u32_unchecked(y);
         //~^ ERROR
+        let y: i32 = u32::from('🐱').cast_signed();
+        //~^ ERROR
+        let y: char = char::from_u32_unchecked(i32::cast_unsigned(y));
+        //~^ ERROR
 
         let x: u16 = i16::cast_unsigned(8i16);
         //~^ ERROR
@@ -72,6 +76,11 @@ fn main() {
         let y: u64 = f64::to_bits(2.0);
         //~^ ERROR
 
+        let y: f64 = f64::from_bits(i64::cast_unsigned(1i64));
+        //~^ ERROR
+        let y: i64 = f64::to_bits(1f64).cast_signed();
+        //~^ ERROR
+
         let z: bool = (1u8 == 1);
         //~^ ERROR
         let z: u8 = (z) as u8;
diff --git a/tests/ui/transmute/unnecessary-transmutation.rs b/tests/ui/transmute/unnecessary-transmutation.rs
index 6b979263c56..b9de529f1cc 100644
--- a/tests/ui/transmute/unnecessary-transmutation.rs
+++ b/tests/ui/transmute/unnecessary-transmutation.rs
@@ -49,6 +49,10 @@ fn main() {
         //~^ ERROR
         let y: char = transmute(y);
         //~^ ERROR
+        let y: i32 = transmute('🐱');
+        //~^ ERROR
+        let y: char = transmute(y);
+        //~^ ERROR
 
         let x: u16 = transmute(8i16);
         //~^ ERROR
@@ -72,6 +76,11 @@ fn main() {
         let y: u64 = transmute(2.0);
         //~^ ERROR
 
+        let y: f64 = transmute(1i64);
+        //~^ ERROR
+        let y: i64 = transmute(1f64);
+        //~^ ERROR
+
         let z: bool = transmute(1u8);
         //~^ ERROR
         let z: u8 = transmute(z);
diff --git a/tests/ui/transmute/unnecessary-transmutation.stderr b/tests/ui/transmute/unnecessary-transmutation.stderr
index b661aa13c98..a19f1bebf16 100644
--- a/tests/ui/transmute/unnecessary-transmutation.stderr
+++ b/tests/ui/transmute/unnecessary-transmutation.stderr
@@ -154,82 +154,108 @@ LL |         let y: char = transmute(y);
    = help: consider `char::from_u32(…).unwrap()`
 
 error: unnecessary transmute
-  --> $DIR/unnecessary-transmutation.rs:53:22
+  --> $DIR/unnecessary-transmutation.rs:52:22
+   |
+LL |         let y: i32 = transmute('🐱');
+   |                      ^^^^^^^^^^^^^^^ help: replace this with: `u32::from('🐱').cast_signed()`
+
+error: unnecessary transmute
+  --> $DIR/unnecessary-transmutation.rs:54:23
+   |
+LL |         let y: char = transmute(y);
+   |                       ^^^^^^^^^^^^ help: replace this with: `char::from_u32_unchecked(i32::cast_unsigned(y))`
+   |
+   = help: consider `char::from_u32(i32::cast_unsigned(…)).unwrap()`
+
+error: unnecessary transmute
+  --> $DIR/unnecessary-transmutation.rs:57:22
    |
 LL |         let x: u16 = transmute(8i16);
    |                      ^^^^^^^^^^^^^^^ help: replace this with: `i16::cast_unsigned(8i16)`
 
 error: unnecessary transmute
-  --> $DIR/unnecessary-transmutation.rs:55:22
+  --> $DIR/unnecessary-transmutation.rs:59:22
    |
 LL |         let x: i16 = transmute(x);
    |                      ^^^^^^^^^^^^ help: replace this with: `u16::cast_signed(x)`
 
 error: unnecessary transmute
-  --> $DIR/unnecessary-transmutation.rs:57:22
+  --> $DIR/unnecessary-transmutation.rs:61:22
    |
 LL |         let x: u32 = transmute(4i32);
    |                      ^^^^^^^^^^^^^^^ help: replace this with: `i32::cast_unsigned(4i32)`
 
 error: unnecessary transmute
-  --> $DIR/unnecessary-transmutation.rs:59:22
+  --> $DIR/unnecessary-transmutation.rs:63:22
    |
 LL |         let x: i32 = transmute(x);
    |                      ^^^^^^^^^^^^ help: replace this with: `u32::cast_signed(x)`
 
 error: unnecessary transmute
-  --> $DIR/unnecessary-transmutation.rs:61:22
+  --> $DIR/unnecessary-transmutation.rs:65:22
    |
 LL |         let x: u64 = transmute(7i64);
    |                      ^^^^^^^^^^^^^^^ help: replace this with: `i64::cast_unsigned(7i64)`
 
 error: unnecessary transmute
-  --> $DIR/unnecessary-transmutation.rs:63:22
+  --> $DIR/unnecessary-transmutation.rs:67:22
    |
 LL |         let x: i64 = transmute(x);
    |                      ^^^^^^^^^^^^ help: replace this with: `u64::cast_signed(x)`
 
 error: unnecessary transmute
-  --> $DIR/unnecessary-transmutation.rs:66:22
+  --> $DIR/unnecessary-transmutation.rs:70:22
    |
 LL |         let y: f32 = transmute(1u32);
    |                      ^^^^^^^^^^^^^^^ help: replace this with: `f32::from_bits(1u32)`
 
 error: unnecessary transmute
-  --> $DIR/unnecessary-transmutation.rs:68:22
+  --> $DIR/unnecessary-transmutation.rs:72:22
    |
 LL |         let y: u32 = transmute(y);
    |                      ^^^^^^^^^^^^ help: replace this with: `f32::to_bits(y)`
 
 error: unnecessary transmute
-  --> $DIR/unnecessary-transmutation.rs:70:22
+  --> $DIR/unnecessary-transmutation.rs:74:22
    |
 LL |         let y: f64 = transmute(3u64);
    |                      ^^^^^^^^^^^^^^^ help: replace this with: `f64::from_bits(3u64)`
 
 error: unnecessary transmute
-  --> $DIR/unnecessary-transmutation.rs:72:22
+  --> $DIR/unnecessary-transmutation.rs:76:22
    |
 LL |         let y: u64 = transmute(2.0);
    |                      ^^^^^^^^^^^^^^ help: replace this with: `f64::to_bits(2.0)`
 
 error: unnecessary transmute
-  --> $DIR/unnecessary-transmutation.rs:75:23
+  --> $DIR/unnecessary-transmutation.rs:79:22
+   |
+LL |         let y: f64 = transmute(1i64);
+   |                      ^^^^^^^^^^^^^^^ help: replace this with: `f64::from_bits(i64::cast_unsigned(1i64))`
+
+error: unnecessary transmute
+  --> $DIR/unnecessary-transmutation.rs:81:22
+   |
+LL |         let y: i64 = transmute(1f64);
+   |                      ^^^^^^^^^^^^^^^ help: replace this with: `f64::to_bits(1f64).cast_signed()`
+
+error: unnecessary transmute
+  --> $DIR/unnecessary-transmutation.rs:84:23
    |
 LL |         let z: bool = transmute(1u8);
    |                       ^^^^^^^^^^^^^^ help: replace this with: `(1u8 == 1)`
 
 error: unnecessary transmute
-  --> $DIR/unnecessary-transmutation.rs:77:21
+  --> $DIR/unnecessary-transmutation.rs:86:21
    |
 LL |         let z: u8 = transmute(z);
    |                     ^^^^^^^^^^^^ help: replace this with: `(z) as u8`
 
 error: unnecessary transmute
-  --> $DIR/unnecessary-transmutation.rs:82:21
+  --> $DIR/unnecessary-transmutation.rs:91:21
    |
 LL |         let z: i8 = transmute(z);
    |                     ^^^^^^^^^^^^ help: replace this with: `(z) as i8`
 
-error: aborting due to 32 previous errors
+error: aborting due to 36 previous errors