expand env! with def-site context

src/librustc_builtin_macros/env.rs

@@ -77,6 +77,7 @@ pub fn expand_env<'cx>(
         return DummyResult::any(sp);
     }
 
+    let sp = cx.with_def_site_ctxt(sp);
     let e = match env::var(&*var.as_str()) {
         Err(_) => {
             cx.span_err(sp, &msg.as_str());

src/test/ui/extenv/extenv-not-defined-custom.stderr

@@ -3,6 +3,8 @@ error: my error message
    |
 LL | fn main() { env!("__HOPEFULLY_NOT_DEFINED__", "my error message"); }
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to previous error
 

src/test/ui/extenv/extenv-not-defined-default.stderr

@@ -3,6 +3,8 @@ error: environment variable `__HOPEFULLY_NOT_DEFINED__` not defined
    |
 LL |     env!("__HOPEFULLY_NOT_DEFINED__");
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to previous error
 

src/test/ui/extenv/issue-55897.stderr

@@ -3,6 +3,8 @@ error: environment variable `NON_EXISTENT` not defined
    |
 LL |     include!(concat!(env!("NON_EXISTENT"), "/data.rs"));
    |                      ^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: suffixes on a string literal are invalid
   --> $DIR/issue-55897.rs:16:22

src/test/ui/macros/macros-nonfatal-errors.stderr

@@ -47,6 +47,8 @@ error: environment variable `RUST_HOPEFULLY_THIS_DOESNT_EXIST` not defined
    |
 LL |     env!("RUST_HOPEFULLY_THIS_DOESNT_EXIST");
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: format argument must be a string literal
   --> $DIR/macros-nonfatal-errors.rs:23:13