Add UI tests for inherent associated item import attempts

Author: CoCo-Japan-pan

tests/ui/imports/import-inherent-148009.rs

@@ -0,0 +1,68 @@
+//! Check that when the feature `import_trait_associated_functions` is enabled,
+//! and one trys to import inherent associated items, the error message is
+//! updated to reflect that only trait associated items can be imported.
+//!
+//! Regression test for <https://github.com/rust-lang/rust/issues/148009>.
+
+//@ check-fail
+
+#![feature(import_trait_associated_functions, extern_types)]
+
+pub struct TestStruct;
+
+impl TestStruct {
+    pub fn m1() {}
+    pub const C1: usize = 0;
+}
+
+pub use self::TestStruct::{C1, m1};
+//~^ ERROR unresolved import `self::TestStruct` [E0432]
+//~| NOTE `TestStruct` is a struct, not a module or a trait
+//~| NOTE cannot import inherent associated items, only trait associated items
+
+pub union TestUnion {
+    pub f: f32,
+    pub i: i32,
+}
+
+impl TestUnion {
+    pub fn m2() {}
+    pub const C2: usize = 0;
+}
+
+pub use self::TestUnion::{C2, m2};
+//~^ ERROR unresolved import `self::TestUnion` [E0432]
+//~| NOTE `TestUnion` is a union, not a module or a trait
+//~| NOTE cannot import inherent associated items, only trait associated items
+
+pub enum TestEnum {
+    V1,
+    V2,
+}
+
+impl TestEnum {
+    pub fn m3() {}
+    pub const C3: usize = 0;
+}
+
+pub use self::TestEnum::{C3, m3};
+//~^ ERROR unresolved imports `self::TestEnum::C3`, `self::TestEnum::m3` [E0432]
+//~| NOTE no `m3` in `TestEnum`
+//~| NOTE no `C3` in `TestEnum`
+//~| NOTE cannot import inherent associated items, only trait associated items
+
+extern "C" {
+    pub type TestForeignTy;
+}
+
+impl TestForeignTy {
+    pub fn m4() {}
+    pub const C4: usize = 0;
+}
+
+pub use self::TestForeignTy::{C4, m4};
+//~^ ERROR unresolved import `self::TestForeignTy` [E0432]
+//~| NOTE `TestForeignTy` is a foreign type, not a module or a trait
+//~| NOTE cannot import inherent associated items, only trait associated items
+
+fn main() {}

tests/ui/imports/import-inherent-148009.stderr

@@ -0,0 +1,37 @@
+error[E0432]: unresolved import `self::TestStruct`
+  --> $DIR/import-inherent-148009.rs:18:15
+   |
+LL | pub use self::TestStruct::{C1, m1};
+   |               ^^^^^^^^^^ `TestStruct` is a struct, not a module or a trait
+   |
+   = note: cannot import inherent associated items, only trait associated items
+
+error[E0432]: unresolved import `self::TestUnion`
+  --> $DIR/import-inherent-148009.rs:33:15
+   |
+LL | pub use self::TestUnion::{C2, m2};
+   |               ^^^^^^^^^ `TestUnion` is a union, not a module or a trait
+   |
+   = note: cannot import inherent associated items, only trait associated items
+
+error[E0432]: unresolved imports `self::TestEnum::C3`, `self::TestEnum::m3`
+  --> $DIR/import-inherent-148009.rs:48:26
+   |
+LL | pub use self::TestEnum::{C3, m3};
+   |                          ^^  ^^ no `m3` in `TestEnum`
+   |                          |
+   |                          no `C3` in `TestEnum`
+   |
+   = note: cannot import inherent associated items, only trait associated items
+
+error[E0432]: unresolved import `self::TestForeignTy`
+  --> $DIR/import-inherent-148009.rs:63:15
+   |
+LL | pub use self::TestForeignTy::{C4, m4};
+   |               ^^^^^^^^^^^^^ `TestForeignTy` is a foreign type, not a module or a trait
+   |
+   = note: cannot import inherent associated items, only trait associated items
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0432`.