fix invalid unresolved imports errors the asterisk wildcard syntax causes

use a path variabale

compiler/rustc_resolve/src/imports.rs

@@ -720,7 +720,9 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
                     note: Vec::new(),
                     suggestion: None,
                 };
-                errors.push((path, err));
+                if path.contains("::") {
+                    errors.push((path, err))
+                }
             }
         }
 

src/test/ui/rust-2018/unresolved-asterisk-imports.rs

@@ -0,0 +1,6 @@
+// edition:2018
+
+use not_existing_crate::*; //~ ERROR unresolved import `not_existing_crate
+use std as foo;
+
+fn main() {}

src/test/ui/rust-2018/unresolved-asterisk-imports.stderr

@@ -0,0 +1,9 @@
+error[E0432]: unresolved import `not_existing_crate`
+  --> $DIR/unresolved-asterisk-imports.rs:3:5
+   |
+LL | use not_existing_crate::*;
+   |     ^^^^^^^^^^^^^^^^^^ use of undeclared crate or module `not_existing_crate`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0432`.

src/test/ui/unresolved/unresolved-asterisk-imports.rs

@@ -0,0 +1,4 @@
+use not_existing_crate::*; //~ ERROR unresolved import `not_existing_crate
+use std as foo;
+
+fn main() {}

src/test/ui/unresolved/unresolved-asterisk-imports.stderr

@@ -0,0 +1,9 @@
+error[E0432]: unresolved import `not_existing_crate`
+  --> $DIR/unresolved-asterisk-imports.rs:1:5
+   |
+LL | use not_existing_crate::*;
+   |     ^^^^^^^^^^^^^^^^^^ maybe a missing crate `not_existing_crate`?
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0432`.