Remove scalable simd check from is_trivially_pure_clone_copy

Author: JamieCunliffe

compiler/rustc_middle/src/ty/sty.rs

@@ -1851,10 +1851,6 @@ impl<'tcx> Ty<'tcx> {
     /// This is mostly useful for optimizations, as these are the types
     /// on which we can replace cloning with dereferencing.
     pub fn is_trivially_pure_clone_copy(self) -> bool {
-        if self.is_scalable_simd() {
-            return true;
-        }
-
         match self.kind() {
             ty::Bool | ty::Char | ty::Never => true,
 

compiler/rustc_mir_build/src/build/misc.rs

@@ -61,7 +61,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
     pub(crate) fn consume_by_copy_or_move(&self, place: Place<'tcx>) -> Operand<'tcx> {
         let tcx = self.tcx;
         let ty = place.ty(&self.local_decls, tcx).ty;
-        if !self.infcx.type_is_copy_modulo_regions(self.param_env, ty) {
+        if !self.infcx.type_is_copy_modulo_regions(self.param_env, ty) && !ty.is_scalable_simd() {
             Operand::Move(place)
         } else {
             Operand::Copy(place)

tests/ui/simd/scalable/disallow-union.rs

@@ -6,7 +6,9 @@ pub struct ScalableSimdFloat {
 }
 
 pub union Invalid {
-    x: ScalableSimdFloat, //~ ERROR E0800
+    x: ScalableSimdFloat,
+    //~^ ERROR E0740
+    //~^^ ERROR E0800
     other: i32,
 }
 

tests/ui/simd/scalable/disallow-union.stderr

@@ -4,6 +4,19 @@ error[E0800]: Scalable simd types cannot exist within a union
 LL |     x: ScalableSimdFloat,
    |        ^^^^^^^^^^^^^^^^^
 
-error: aborting due to 1 previous error
+error[E0740]: field must implement `Copy` or be wrapped in `ManuallyDrop<...>` to be used in a union
+  --> $DIR/disallow-union.rs:9:5
+   |
+LL |     x: ScalableSimdFloat,
+   |     ^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: union fields must not have drop side-effects, which is currently enforced via either `Copy` or `ManuallyDrop<...>`
+help: wrap the field type in `ManuallyDrop<...>`
+   |
+LL |     x: std::mem::ManuallyDrop<ScalableSimdFloat>,
+   |        +++++++++++++++++++++++                 +
+
+error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0800`.
+Some errors have detailed explanations: E0740, E0800.
+For more information about an error, try `rustc --explain E0740`.