Rollup merge of rust-lang#89447 - FabianWolff:issue-89388, r=davidtwco

Improve error message for missing angle brackets in `[_]::method` Fixes rust-lang#89388.
Manishearth · Oct 4, 2021 · a0e8871 · a0e8871
2 parents d5a5014 + d92c683
commit a0e8871
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diff --git a/compiler/rustc_ast/src/ast.rs b/compiler/rustc_ast/src/ast.rs
@@ -1211,6 +1211,8 @@ impl Expr {
                 }
             }
 
+            ExprKind::Underscore => TyKind::Infer,
+
             // This expression doesn't look like a type syntactically.
             _ => return None,
         };

diff --git a/src/test/ui/parser/issue-89388.rs b/src/test/ui/parser/issue-89388.rs
@@ -0,0 +1,7 @@
+// Regression test for #89388.
+
+fn main() {
+    let option: Option<&[u8]> = Some(b"...");
+    let _ = option.map([_]::to_vec);
+    //~^ ERROR: missing angle brackets in associated item path
+}
diff --git a/src/test/ui/parser/issue-89388.stderr b/src/test/ui/parser/issue-89388.stderr
@@ -0,0 +1,8 @@
+error: missing angle brackets in associated item path
+  --> $DIR/issue-89388.rs:5:24
+   |
+LL |     let _ = option.map([_]::to_vec);
+   |                        ^^^^^^^^^^^ help: try: `<[_]>::to_vec`
+
+error: aborting due to previous error
+