Rust: extract declarations of builtin types

rust/tools/builtins/BUILD.bazel

@@ -0,0 +1,8 @@
+load("//misc/bazel:pkg.bzl", "codeql_pkg_files")
+
+codeql_pkg_files(
+    name = "builtins",
+    srcs = glob(["*.rs"]),
+    prefix = "builtins",
+    visibility = ["//rust:__subpackages__"],
+)

rust/tools/builtins/types.rs

@@ -0,0 +1,25 @@
+// The Language Prelude: https://doc.rust-lang.org/reference/names/preludes.html#language-prelude
+
+// Type namespace
+// Boolean type
+pub struct bool;
+// Textual types
+pub struct char;
+pub struct str;
+// Integer types
+pub struct i8;
+pub struct i16;
+pub struct i32;
+pub struct i64;
+pub struct i128;
+pub struct u8;
+pub struct u16;
+pub struct u32;
+pub struct u64;
+pub struct u128;
+// Machine-dependent integer types
+pub struct usize;
+pub struct isize;
+// floating-point types
+pub struct f32;
+pub struct f64;