Fix Bugzilla 24630 - Casting a bool pointer to a mutable pointer type…

… is unsafe
dlang · Jun 25, 2024 · 5058aa9 · 5058aa9
1 parent b7c32d3
commit 5058aa9
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Showing 2 changed files with 15 additions and 5 deletions.
diff --git a/compiler/src/dmd/safe.d b/compiler/src/dmd/safe.d
@@ -235,6 +235,10 @@ bool isSafeCast(Expression e, Type tfrom, Type tto, ref string msg)
  // Runtime array cast reinterprets data
  if (ttobn.ty == Tbool && tfromn.ty != Tbool && e.op != EXP.arrayLiteral)
  msg = "Source element may have bytes which are not 0 or 1";
+ // Can't alias a bool pointer with a non-bool pointer
+ if (ttobn.ty != Tbool && tfromn.ty == Tbool && ttobn.isMutable() &&
+ e.op != EXP.arrayLiteral)
+ msg = "Target element could be assigned a byte which is not 0 or 1";
 
  // If the struct is opaque we don't know about the struct members then the cast becomes unsafe
  if (ttobn.ty == Tstruct && !(cast(TypeStruct)ttobn).sym.members)

diff --git a/compiler/test/fail_compilation/bool_cast.d b/compiler/test/fail_compilation/bool_cast.d
@@ -2,19 +2,25 @@
 REQUIRED_ARGS: -de -preview=dip1000
 TEST_OUTPUT:
 ---
-fail_compilation/bool_cast.d(15): Deprecation: cast from `ubyte[]` to `bool[]` not allowed in safe code
-fail_compilation/bool_cast.d(15): Source element may have bytes which are not 0 or 1
-fail_compilation/bool_cast.d(19): Deprecation: cast from `int*` to `bool*` not allowed in safe code
-fail_compilation/bool_cast.d(19): Source element may have bytes which are not 0 or 1
+fail_compilation/bool_cast.d(17): Deprecation: cast from `ubyte[]` to `bool[]` not allowed in safe code
+fail_compilation/bool_cast.d(17): Source element may have bytes which are not 0 or 1
+fail_compilation/bool_cast.d(22): Deprecation: cast from `int*` to `bool*` not allowed in safe code
+fail_compilation/bool_cast.d(22): Source element may have bytes which are not 0 or 1
+fail_compilation/bool_cast.d(24): Deprecation: cast from `bool*` to `byte*` not allowed in safe code
+fail_compilation/bool_cast.d(24): Target element could be assigned a byte which is not 0 or 1
 ---
 */
 
 void main() @safe
 {
  ubyte[] a = [2, 4];
  auto b = cast(bool[]) a; // reinterprets a's data
- auto c = cast(bool[]) [2, 4]; // literal cast applies to each element
+ auto c = cast(bool[]) [2, 4]; // OK, literal cast applies to each element
+ auto d = cast(const(byte)[]) b; // OK, result's elements are const
 
  int i = 2;
  auto p = cast(bool*) &i;
+ bool v;
+ auto bp = cast(byte*) &v;
+ *bp = 2; // v is now invalid
 }