Add some tests in number evaluvation and hover to prevent regression

Added a test near positive extermes and two test near negative
extermes as well one for 0.
Added a test using the `as` cast and one with comparison with 0.

crates/hir-ty/src/consteval/tests.rs

@@ -2018,6 +2018,57 @@ fn consts() {
     "#,
         6,
     );
+
+    check_number(
+        r#"
+    const F1: i32 = 2147483647;
+    const F2: i32 = F1 - 25;
+    const GOAL: i32 = F2;
+    "#,
+        2147483622,
+    );
+
+    check_number(
+        r#"
+    const F1: i32 = -2147483648;
+    const F2: i32 = F1 + 18;
+    const GOAL: i32 = F2;
+    "#,
+        -2147483630,
+    );
+
+    check_number(
+        r#"
+    const F1: i32 = 10;
+    const F2: i32 = F1 - 20;
+    const GOAL: i32 = F2;
+    "#,
+        -10,
+    );
+
+    check_number(
+        r#"
+    const F1: i32 = 25;
+    const F2: i32 = F1 - 25;
+    const GOAL: i32 = F2;
+    "#,
+        0,
+    );
+
+    check_number(
+        r#"
+    const A: i32 = -2147483648;
+    const GOAL: bool = A > 0;
+    "#,
+        0,
+    );
+
+    check_number(
+        r#"
+    const GOAL: i64 = (-2147483648_i32) as i64;
+    "#,
+        -2147483648,
+    );
 }
 
 #[test]

crates/ide/src/hover/tests.rs

@@ -779,6 +779,39 @@ const foo$0: u32 = {
             ```
         "#]],
     );
+
+    check(
+        r#"const FOO$0: i32 = -2147483648;"#,
+        expect![[r#"
+            *FOO*
+
+            ```rust
+            test
+            ```
+
+            ```rust
+            const FOO: i32 = -2147483648 (0x80000000)
+            ```
+        "#]],
+    );
+
+    check(
+        r#"
+        const FOO: i32 = -2147483648;
+        const BAR$0: bool = FOO > 0;
+        "#,
+        expect![[r#"
+            *BAR*
+
+            ```rust
+            test
+            ```
+
+            ```rust
+            const BAR: bool = false
+            ```
+        "#]],
+    );
 }
 
 #[test]