From: Emanuele Micheletti <micheletti.emanuele@hotmail.com>
Date: Fri, 31 Mar 2023 10:50:36 +0000 (+0200)
Subject: gccrs: Fix bad cast as a char
X-Git-Tag: basepoints/gcc-15~2702
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=bdb4e2930ecbb96289819833c495ac59214b38b5;p=thirdparty%2Fgcc.git

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 08bdcbb4a5aa..8e5e65eb22c7 100644
--- 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
index 000000000000..ecc10c1490a6
--- /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;
+}