Auto merge of #15641 - alibektas:15598/fix_into_to_from, r=Veykril

fix: preceding QualifiedPathType for into_to_from assist

fixes #15598

Author: bors

crates/ide-assists/src/handlers/into_to_qualified_from.rs

@@ -52,17 +52,25 @@ pub(crate) fn into_to_qualified_from(acc: &mut Assists, ctx: &AssistContext<'_>)
         == FamousDefs(sema, scope.krate()).core_convert_Into()?
     {
         let type_call = sema.type_of_expr(&method_call.clone().into())?;
-        let type_call_disp =
-            type_call.adjusted().display_source_code(db, scope.module().into(), true).ok()?;
+        let adjusted_tc = type_call.adjusted();
 
+        if adjusted_tc.contains_unknown() {
+            return None;
+        }
+
+        let sc = adjusted_tc.display_source_code(db, scope.module().into(), true).ok()?;
         acc.add(
             AssistId("into_to_qualified_from", AssistKind::Generate),
             "Convert `into` to fully qualified `from`",
             nameref.syntax().text_range(),
             |edit| {
                 edit.replace(
                     method_call.syntax().text_range(),
-                    format!("{}::from({})", type_call_disp, receiver),
+                    if sc.chars().all(|c| c.is_alphanumeric() || c == ':') {
+                        format!("{}::from({})", sc, receiver)
+                    } else {
+                        format!("<{}>::from({})", sc, receiver)
+                    },
                 );
             },
         );
@@ -199,6 +207,66 @@ mod C {
 fn main() -> () {
     let a: A = A;
     let b: C::B = C::B::from(a);
+}"#,
+        )
+    }
+
+    #[test]
+    fn preceding_type_qualifier() {
+        check_assist(
+            into_to_qualified_from,
+            r#"
+//- minicore: from
+impl From<(i32,i32)> for [i32;2] {
+    fn from(value: (i32,i32)) -> Self {
+        [value.0, value.1]
+    }
+}
+
+fn tuple_to_array() -> [i32; 2] {
+    (0,1).in$0to()
+}"#,
+            r#"
+impl From<(i32,i32)> for [i32;2] {
+    fn from(value: (i32,i32)) -> Self {
+        [value.0, value.1]
+    }
+}
+
+fn tuple_to_array() -> [i32; 2] {
+    <[i32; 2]>::from((0,1))
+}"#,
+        )
+    }
+
+    #[test]
+    fn type_with_gens() {
+        check_assist(
+            into_to_qualified_from,
+            r#"
+//- minicore: from
+struct StructA<Gen>(Gen);
+
+impl From<i32> for StructA<i32> {
+    fn from(value: i32) -> Self {
+        StructA(value + 1)
+    }
+}
+
+fn main() -> () {
+    let a: StructA<i32> = 3.in$0to();
+}"#,
+            r#"
+struct StructA<Gen>(Gen);
+
+impl From<i32> for StructA<i32> {
+    fn from(value: i32) -> Self {
+        StructA(value + 1)
+    }
+}
+
+fn main() -> () {
+    let a: StructA<i32> = <StructA<i32>>::from(3);
 }"#,
         )
     }