collect attrs in const block expr

compiler/rustc_resolve/src/def_collector.rs

@@ -343,6 +343,9 @@ impl<'a, 'b, 'tcx> visit::Visitor<'a> for DefCollector<'a, 'b, 'tcx> {
                 self.create_def(expr.id, kw::Empty, DefKind::Closure, expr.span)
             }
             ExprKind::ConstBlock(ref constant) => {
+                for attr in &expr.attrs {
+                    visit::walk_attribute(self, attr);
+                }
                 let def = self.create_def(
                     constant.id,
                     kw::Empty,

tests/ui/resolve/path-attr-in-const-block.rs

@@ -0,0 +1,9 @@
+// issue#126516
+// issue#126647
+
+fn main() {
+    const {
+        #![path = foo!()]
+        //~^ ERROR: cannot find macro `foo` in this scope
+    }
+}

tests/ui/resolve/path-attr-in-const-block.stderr

@@ -0,0 +1,8 @@
+error: cannot find macro `foo` in this scope
+  --> $DIR/path-attr-in-const-block.rs:6:19
+   |
+LL |         #![path = foo!()]
+   |                   ^^^
+
+error: aborting due to 1 previous error
+