Add regression test for issue 142649

Author: dtolnay

tests/ui/deprecation/deprecated-expr-precedence.rs

@@ -0,0 +1,8 @@
+//@ check-fail
+//@ compile-flags: --crate-type=lib
+
+// Regression test for issue 142649
+pub fn public() {
+    #[deprecated] 0
+    //~^ ERROR mismatched types
+}

tests/ui/unpretty/deprecated-attr.rs

@@ -16,3 +16,8 @@ pub struct SinceAndNote;
 
 #[deprecated(note = "here's why this is deprecated", since = "1.2.3")]
 pub struct FlippedOrder;
+
+pub fn f() {
+    // Attribute is ignored here (with a warning), but still preserved in HIR
+    #[deprecated] 0
+}

tests/ui/unpretty/deprecated-attr.stdout

@@ -24,3 +24,12 @@ struct SinceAndNote;
 #[attr = Deprecation {deprecation: Deprecation {since: NonStandard("1.2.3"),
 note: "here's why this is deprecated"}}]
 struct FlippedOrder;
+
+fn f() {
+
+    // Attribute is ignored here (with a warning), but still preserved in HIR
+    #[attr = Deprecation {deprecation:
+    Deprecation {since:
+    Unspecified}}]
+    0
+}