Use correct expr kind when converting pointer offset (#236)

Author: lucic71

cpp2rust/converter/converter.cpp

@@ -3680,6 +3680,7 @@ void Converter::ConvertPointerOffset(clang::Expr *base, clang::Expr *idx,
   PushParen neg_paren(*this, !is_addition);
   {
     PushParen inner(*this);
+    PushExprKind push(*this, ExprKind::RValue);
     Convert(idx);
   }
   StrCat(keyword::kAs, "isize");

tests/unit/out/unsafe/string_h.rs

@@ -211,6 +211,13 @@ pub unsafe fn test_strlen_5() {
             as i32)
             != 0)
     );
+    let buf: [libc::c_char; 8] = std::mem::transmute(*b"one\0two\0");
+    let mut first: *const libc::c_char = buf.as_ptr();
+    let mut second: *const libc::c_char =
+        (&buf[((libc::strlen(first)).wrapping_add(1_usize))] as *const libc::c_char);
+    assert!(
+        ((((libc::strcmp(second, (c"two".as_ptr().cast_mut()).cast_const())) == (0)) as i32) != 0)
+    );
 }
 pub unsafe fn test_strcmp_6() {
     assert!(

tests/unit/string_h.c

@@ -50,6 +50,10 @@ static void test_strlen(void) {
   assert(strlen("") == 0);
   assert(strlen("hello") == 5);
   assert(strlen("hello world") == 11);
+  const char buf[] = "one\0two";
+  const char *first = buf;
+  const char *second = &buf[strlen(first) + 1];
+  assert(strcmp(second, "two") == 0);
 }
 
 static void test_strcmp(void) {