Merge #5698

5698: Display the value of a const on the hover r=jonas-schievink a=JmPotato

Signed-off-by: JmPotato <[email protected]>

Close #4051 

To display the value of a const, I modified the implementation of `ShortLabel` for `ast::Const`.

Co-authored-by: JmPotato <[email protected]>

Author: bors[bot]

crates/ra_ide/src/display/short_label.rs

@@ -61,7 +61,11 @@ impl ShortLabel for ast::TypeAlias {
 
 impl ShortLabel for ast::Const {
     fn short_label(&self) -> Option<String> {
-        short_label_from_ty(self, self.ty(), "const ")
+        let mut new_buf = short_label_from_ty(self, self.ty(), "const ")?;
+        if let Some(expr) = self.body() {
+            format_to!(new_buf, " = {}", expr.syntax());
+        }
+        Some(new_buf)
     }
 }
 

crates/ra_ide/src/hover.rs

@@ -590,16 +590,16 @@ fn main() {
     #[test]
     fn hover_const_static() {
         check(
-            r#"const foo<|>: u32 = 0;"#,
+            r#"const foo<|>: u32 = 123;"#,
             expect![[r#"
                 *foo*
                 ```rust
-                const foo: u32
+                const foo: u32 = 123
                 ```
             "#]],
         );
         check(
-            r#"static foo<|>: u32 = 0;"#,
+            r#"static foo<|>: u32 = 456;"#,
             expect![[r#"
                 *foo*
                 ```rust
@@ -834,7 +834,7 @@ fn main() {
             expect![[r#"
                 *C*
                 ```rust
-                const C: u32
+                const C: u32 = 1
                 ```
             "#]],
         )