diagnostics: account for glob shadowing when linting redundant imports

Co-Authored-By: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>

tests/ui/lint/use-redundant/issue-92904.rs

@@ -0,0 +1,17 @@
+// check-pass
+
+pub struct Foo(bar::Bar);
+
+pub mod bar {
+    pub struct Foo(pub Bar);
+    pub struct Bar(pub char);
+}
+
+pub fn warning() -> Foo {
+    use bar::*;
+    #[deny(unused_imports)]
+    use self::Foo; // no error
+    Foo(Bar('a'))
+}
+
+fn main() {}

tests/ui/lint/use-redundant/use-redundant-glob-parent.rs

@@ -0,0 +1,16 @@
+// check-pass
+#![warn(unused_imports)]
+
+pub mod bar {
+    pub struct Foo(pub Bar);
+    pub struct Bar(pub char);
+}
+
+use bar::*;
+
+pub fn warning() -> Foo {
+    use bar::Foo; //~ WARNING imported redundantly
+    Foo(Bar('a'))
+}
+
+fn main() {}

tests/ui/lint/use-redundant/use-redundant-glob-parent.stderr

@@ -0,0 +1,17 @@
+warning: the item `Foo` is imported redundantly
+  --> $DIR/use-redundant-glob-parent.rs:12:9
+   |
+LL | use bar::*;
+   |     ------ the item `Foo` is already imported here
+...
+LL |     use bar::Foo;
+   |         ^^^^^^^^
+   |
+note: the lint level is defined here
+  --> $DIR/use-redundant-glob-parent.rs:2:9
+   |
+LL | #![warn(unused_imports)]
+   |         ^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+

tests/ui/lint/use-redundant/use-redundant-glob.rs

@@ -0,0 +1,15 @@
+// check-pass
+#![warn(unused_imports)]
+
+pub mod bar {
+    pub struct Foo(pub Bar);
+    pub struct Bar(pub char);
+}
+
+pub fn warning() -> bar::Foo {
+    use bar::*;
+    use bar::Foo; //~ WARNING imported redundantly
+    Foo(Bar('a'))
+}
+
+fn main() {}

tests/ui/lint/use-redundant/use-redundant-glob.stderr

@@ -0,0 +1,16 @@
+warning: the item `Foo` is imported redundantly
+  --> $DIR/use-redundant-glob.rs:11:9
+   |
+LL |     use bar::*;
+   |         ------ the item `Foo` is already imported here
+LL |     use bar::Foo;
+   |         ^^^^^^^^
+   |
+note: the lint level is defined here
+  --> $DIR/use-redundant-glob.rs:2:9
+   |
+LL | #![warn(unused_imports)]
+   |         ^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+

tests/ui/lint/use-redundant/use-redundant-multiple-namespaces.rs

@@ -0,0 +1,21 @@
+// check-pass
+#![allow(nonstandard_style)]
+
+pub mod bar {
+    pub struct Foo { pub bar: Bar }
+    pub struct Bar(pub char);
+}
+
+pub mod x {
+    use crate::bar;
+    pub const Foo: bar::Bar = bar::Bar('a');
+}
+
+pub fn warning() -> bar::Foo {
+    #![deny(unused_imports)] // no error
+    use bar::*;
+    use x::Foo;
+    Foo { bar: Foo }
+}
+
+fn main() {}

tests/ui/lint/use-redundant/use-redundant-not-parent.rs

@@ -0,0 +1,19 @@
+// check-pass
+
+pub mod bar {
+    pub struct Foo(pub Bar);
+    pub struct Bar(pub char);
+}
+
+pub mod x {
+    pub struct Foo(pub crate::bar::Bar);
+}
+
+pub fn warning() -> x::Foo {
+    use bar::*;
+    #[deny(unused_imports)]
+    use x::Foo; // no error
+    Foo(Bar('a'))
+}
+
+fn main() {}