gccrs: Fix bad cast as a char

In rust cast to char is allowed only from u8 type.
This patch handles fix the case when the type is infered from an integer value,
allowing only the u8 case'

Fixes #2027

gcc/rust/ChangeLog:

	* typecheck/rust-casts.cc (TypeCastRules::cast_rules):
	case INTEGRAL handles TypeKind::CHAR

gcc/testsuite/ChangeLog:

	* rust/compile/cast5.rs: New test.

Signed-off-by: Emanuele Micheletti <micheletti.emanuele@hotmail.com>

diff --git a/gcc/rust/typecheck/rust-casts.cc b/gcc/rust/typecheck/rust-casts.cc
index 08bdcbb4a5aa8a339e79c02afc0e49011b1b04e7..8e5e65eb22c77704aa9145526a4a0bbf5bbe7397 100644 (file)
--- a/gcc/rust/typecheck/rust-casts.cc
+++ b/gcc/rust/typecheck/rust-casts.cc
@@ -64,7 +64,6 @@ TypeCastRules::cast_rules ()
 
   rust_debug ("cast_rules from={%s} to={%s}", from_type->debug_str ().c_str (),
              to.get_ty ()->debug_str ().c_str ());
-
   switch (from_type->get_kind ())
     {
       case TyTy::TypeKind::INFER: {
@@ -79,7 +78,21 @@ TypeCastRules::cast_rules ()
          case TyTy::InferType::InferTypeKind::INTEGRAL:
            switch (to.get_ty ()->get_kind ())
              {
-             case TyTy::TypeKind::CHAR:
+               case TyTy::TypeKind::CHAR: {
+                 // only u8 and char
+                 bool was_uint
+                   = from.get_ty ()->get_kind () == TyTy::TypeKind::UINT;
+                 bool was_u8
+                   = was_uint
+                     && (static_cast<TyTy::UintType *> (from.get_ty ())
+                           ->get_uint_kind ()
+                         == TyTy::UintType::UintKind::U8);
+                 if (was_u8)
+                   return TypeCoercionRules::CoercionResult{
+                     {}, to.get_ty ()->clone ()};
+               }
+               break;
+
              case TyTy::TypeKind::USIZE:
              case TyTy::TypeKind::ISIZE:
              case TyTy::TypeKind::UINT:

diff --git a/gcc/testsuite/rust/compile/cast5.rs b/gcc/testsuite/rust/compile/cast5.rs
new file mode 100644 (file)
index 0000000..ecc10c1
--- /dev/null
+++ b/gcc/testsuite/rust/compile/cast5.rs
@@ -0,0 +1,12 @@
+fn main() {
+    const A: char = 0x1F888 as char;
+    // { dg-error "invalid cast .<integer>. to .char." "" { target *-*-* } .-1 }
+    const B: char = 129160 as char;
+    // { dg-error "invalid cast .<integer>. to .char." "" { target *-*-* } .-1 }
+    const C: i32 = 42;
+    const D: char = C as char;
+    // { dg-error "invalid cast .i32. to .char." "" { target *-*-* } .-1 }
+    const E: char = '\u{01F888}';
+    const F: u8 = 42; 
+    const G: char= F as char;
+}