From fbf1efb949b9d76b4964b7b6a7a606de116ecb46 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Esteban=20K=C3=BCber?= <esteban@kuber.com.ar>
Date: Thu, 15 Aug 2019 11:46:52 -0700
Subject: [PATCH] Do not suggest `try_into` for base types inside of macro
 expansions

---
 src/librustc_typeck/check/demand.rs                   |  4 ++++
 .../ui/suggestions/dont-suggest-try_into-in-macros.rs |  3 +++
 .../dont-suggest-try_into-in-macros.stderr            | 11 +++++++++++
 3 files changed, 18 insertions(+)
 create mode 100644 src/test/ui/suggestions/dont-suggest-try_into-in-macros.rs
 create mode 100644 src/test/ui/suggestions/dont-suggest-try_into-in-macros.stderr

diff --git a/src/librustc_typeck/check/demand.rs b/src/librustc_typeck/check/demand.rs
index ed25601208ad1..f3b56b31b775d 100644
--- a/src/librustc_typeck/check/demand.rs
+++ b/src/librustc_typeck/check/demand.rs
@@ -554,6 +554,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // FIXME(estebank): modify once we decide to suggest `as` casts
             return false;
         }
+        if !self.tcx.sess.source_map().span_to_filename(expr.span).is_real() {
+            // Ignore if span is from within a macro.
+            return false;
+        }
 
         // If casting this expression to a given numeric type would be appropriate in case of a type
         // mismatch.
diff --git a/src/test/ui/suggestions/dont-suggest-try_into-in-macros.rs b/src/test/ui/suggestions/dont-suggest-try_into-in-macros.rs
new file mode 100644
index 0000000000000..d625199c937c7
--- /dev/null
+++ b/src/test/ui/suggestions/dont-suggest-try_into-in-macros.rs
@@ -0,0 +1,3 @@
+fn main() {
+    assert_eq!(10u64, 10usize); //~ ERROR mismatched types
+}
diff --git a/src/test/ui/suggestions/dont-suggest-try_into-in-macros.stderr b/src/test/ui/suggestions/dont-suggest-try_into-in-macros.stderr
new file mode 100644
index 0000000000000..f04306997a9ed
--- /dev/null
+++ b/src/test/ui/suggestions/dont-suggest-try_into-in-macros.stderr
@@ -0,0 +1,11 @@
+error[E0308]: mismatched types
+  --> $DIR/dont-suggest-try_into-in-macros.rs:2:5
+   |
+LL |     assert_eq!(10u64, 10usize);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected u64, found usize
+   |
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.