single owner. borrowed references are "moved"

Cargo.toml

@@ -2,7 +2,3 @@
 name = "basics00"
 version = "0.1.0"
 edition = "2021"
-
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-
-[dependencies]

src/main.rs

@@ -1,12 +1,6 @@
 fn main() {
-    let a = 10;
-    println!("beginning a: {a}");
-    {
-        let a = "hello";
-        println!("inner a: {a}");
-
-        let a = true;
-        println!("shadowed a: {a}");
-    }
-    println!("ending a: {a}");
+    let s1 = String::from("hello");
+    let s2 = s1;
+    println!("{}", s2);
+    //println!("{}", s1);
 }

target/.rustc_info.json

@@ -1 +1 @@
-{"rustc_fingerprint":16320356917333427825,"outputs":{"15697416045686424142":{"success":true,"status":"","code":0,"stdout":"___\nlib___.rlib\nlib___.so\nlib___.so\nlib___.a\nlib___.so\n","stderr":""},"10376369925670944939":{"success":true,"status":"","code":0,"stdout":"___\nlib___.rlib\nlib___.so\nlib___.so\nlib___.a\nlib___.so\n/home/vbatts/.rustup/toolchains/stable-x86_64-unknown-linux-gnu\ndebug_assertions\npanic=\"unwind\"\nproc_macro\ntarget_arch=\"x86_64\"\ntarget_endian=\"little\"\ntarget_env=\"gnu\"\ntarget_family=\"unix\"\ntarget_feature=\"fxsr\"\ntarget_feature=\"sse\"\ntarget_feature=\"sse2\"\ntarget_has_atomic=\"16\"\ntarget_has_atomic=\"32\"\ntarget_has_atomic=\"64\"\ntarget_has_atomic=\"8\"\ntarget_has_atomic=\"ptr\"\ntarget_os=\"linux\"\ntarget_pointer_width=\"64\"\ntarget_vendor=\"unknown\"\nunix\n","stderr":""},"4614504638168534921":{"success":true,"status":"","code":0,"stdout":"rustc 1.66.1 (90743e729 2023-01-10)\nbinary: rustc\ncommit-hash: 90743e7298aca107ddaa0c202a4d3604e29bfeb6\ncommit-date: 2023-01-10\nhost: x86_64-unknown-linux-gnu\nrelease: 1.66.1\nLLVM version: 15.0.2\n","stderr":""}},"successes":{}}
+{"rustc_fingerprint":16320356917333427825,"outputs":{"4614504638168534921":{"success":true,"status":"","code":0,"stdout":"rustc 1.66.1 (90743e729 2023-01-10)\nbinary: rustc\ncommit-hash: 90743e7298aca107ddaa0c202a4d3604e29bfeb6\ncommit-date: 2023-01-10\nhost: x86_64-unknown-linux-gnu\nrelease: 1.66.1\nLLVM version: 15.0.2\n","stderr":""},"10376369925670944939":{"success":true,"status":"","code":0,"stdout":"___\nlib___.rlib\nlib___.so\nlib___.so\nlib___.a\nlib___.so\n/home/vbatts/.rustup/toolchains/stable-x86_64-unknown-linux-gnu\ndebug_assertions\npanic=\"unwind\"\nproc_macro\ntarget_arch=\"x86_64\"\ntarget_endian=\"little\"\ntarget_env=\"gnu\"\ntarget_family=\"unix\"\ntarget_feature=\"fxsr\"\ntarget_feature=\"sse\"\ntarget_feature=\"sse2\"\ntarget_has_atomic=\"16\"\ntarget_has_atomic=\"32\"\ntarget_has_atomic=\"64\"\ntarget_has_atomic=\"8\"\ntarget_has_atomic=\"ptr\"\ntarget_os=\"linux\"\ntarget_pointer_width=\"64\"\ntarget_vendor=\"unknown\"\nunix\n","stderr":""},"15697416045686424142":{"success":true,"status":"","code":0,"stdout":"___\nlib___.rlib\nlib___.so\nlib___.so\nlib___.a\nlib___.so\n","stderr":""}},"successes":{}}