Added support for const generics in impl generation

Author: ivan770

crates/ide_assists/src/handlers/generate_impl.rs

@@ -69,6 +69,17 @@ mod tests {
             "struct Foo<'a, T: Foo<'a>> {$0}",
             "struct Foo<'a, T: Foo<'a>> {}\n\nimpl<'a, T: Foo<'a>> Foo<'a, T> {\n    $0\n}",
         );
+        check_assist(
+            generate_impl,
+            r#"
+            struct MyOwnArray<T, const S: usize> {}$0"#,
+            r#"
+            struct MyOwnArray<T, const S: usize> {}
+
+            impl<T, const S: usize> MyOwnArray<T, S> {
+                $0
+            }"#,
+        );
         check_assist(
             generate_impl,
             r#"
@@ -114,11 +125,11 @@ mod tests {
         check_assist(
             generate_impl,
             r#"
-            struct Defaulted<'a, 'b: 'a, T: Debug + Clone + 'a + 'b = String> {}$0"#,
+            struct Defaulted<'a, 'b: 'a, T: Debug + Clone + 'a + 'b = String, const S: usize> {}$0"#,
             r#"
-            struct Defaulted<'a, 'b: 'a, T: Debug + Clone + 'a + 'b = String> {}
+            struct Defaulted<'a, 'b: 'a, T: Debug + Clone + 'a + 'b = String, const S: usize> {}
 
-            impl<'a, 'b: 'a, T: Debug + Clone + 'a + 'b> Defaulted<'a, 'b, T> {
+            impl<'a, 'b: 'a, T: Debug + Clone + 'a + 'b, const S: usize> Defaulted<'a, 'b, T, S> {
                 $0
             }"#,
         );

crates/ide_assists/src/utils.rs

@@ -434,7 +434,8 @@ fn generate_impl_text_inner(adt: &ast::Adt, trait_text: Option<&str>, code: &str
             }
             buf
         });
-        let generics = lifetimes.chain(type_params).format(", ");
+        let const_params = generic_params.const_params().map(|t| t.syntax().to_string());
+        let generics = lifetimes.chain(type_params).chain(const_params).format(", ");
         format_to!(buf, "<{}>", generics);
     }
     buf.push(' ');
@@ -452,7 +453,11 @@ fn generate_impl_text_inner(adt: &ast::Adt, trait_text: Option<&str>, code: &str
             .type_params()
             .filter_map(|it| it.name())
             .map(|it| SmolStr::from(it.text()));
-        format_to!(buf, "<{}>", lifetime_params.chain(type_params).format(", "))
+        let const_params = generic_params
+            .const_params()
+            .filter_map(|it| it.name())
+            .map(|it| SmolStr::from(it.text()));
+        format_to!(buf, "<{}>", lifetime_params.chain(type_params).chain(const_params).format(", "))
     }
 
     match adt.where_clause() {