Support Self in mir lowering

Author: HKalbasi

crates/hir-ty/src/mir/eval/tests.rs

@@ -613,6 +613,50 @@ fn main() {
     );
 }
 
+#[test]
+fn self_with_capital_s() {
+    check_pass(
+        r#"
+//- minicore: fn, add, copy
+
+struct S1;
+
+impl S1 {
+    fn f() {
+        Self;
+    }
+}
+
+struct S2 {
+    f1: i32,
+}
+
+impl S2 {
+    fn f() {
+        Self { f1: 5 };
+    }
+}
+
+struct S3(i32);
+
+impl S3 {
+    fn f() {
+        Self(2);
+        Self;
+        let this = Self;
+        this(2);
+    }
+}
+
+fn main() {
+    S1::f();
+    S2::f();
+    S3::f();
+}
+        "#,
+    );
+}
+
 #[test]
 fn syscalls() {
     check_pass(

crates/hir-ty/src/mir/lower.rs

@@ -486,13 +486,10 @@ impl<'ctx> MirLowerCtx<'ctx> {
                         );
                         Ok(Some(current))
                     }
-                    ValueNs::FunctionId(_) | ValueNs::StructId(_) => {
+                    ValueNs::FunctionId(_) | ValueNs::StructId(_) | ValueNs::ImplSelf(_) => {
                         // It's probably a unit struct or a zero sized function, so no action is needed.
                         Ok(Some(current))
                     }
-                    it => {
-                        not_supported!("unknown name {it:?} in value name space");
-                    }
                 }
             }
             Expr::If { condition, then_branch, else_branch } => {