Some code actions send more than one snippet text edits

[simrat39]

rust-analyzer version: rust-analyzer 1 (67920f797 2022-09-04)

rustc version: rustc 1.57.0 (f1edd0429 2021-11-29)

minimal repro:

• Have this struct

#[derive(Debug)]
struct Bruh {
    a: i32,
}

• Request code actions when hovered on Debug
• Chose "Convert to manual impl..."

expected result: Only one snippetTextEdit is sent, like in the docs

actual result: More than one snippetTextEdit is sent

|| { {
||     insertTextFormat = 2,
||     newText = "",
||     range = {
||       end = {
||         character = 16,
||         line = 2
||       },
||       start = {
||         character = 0,
||         line = 2
||       }
||     }
||   }, {
||     insertTextFormat = 2,
||     newText = "",
||     range = {
||       end = {
||         character = 0,
||         line = 3
||       },
||       start = {
||         character = 16,
||         line = 2
||       }
||     }
||   }, {
||     insertTextFormat = 2,
||     newText = "\n\nimpl std::fmt::Debug for Bruh {\n    $0fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {\n        f.debug_struct(\"Bruh\").field(\"a\", &self.a).finish()\n    }\n}",
||     range = {
||       end = {
||         character = 1,
||         line = 5
||       },
||       start = {
||         character = 1,
||         line = 5
||       }
||     }
||   } }

(insertTextFormat 2 is a snippetTextEdit)

References:

• https://github.com/L3MON4D3/LuaSnip/issues/235

[matklad]

VS Code got first-class impl, we should align with that: https://github.com/microsoft/vscode/issues/145374#event-7376292737

[nemethf]

Isn't this a duplicate of #11006?

[DropDemBits]

As of #15876, code actions may send more than one edit as a snippet text edit (e.g. generate_trait_from_impl), but only one document may have snippets applied to it. I think this can be closed now that that has been clarified.

Note that we should never generate a snippet text edit that doesn't have placeholders or tabstops in the new text (i.e. the empty snippet edit new text was considered a bug), which the current snippet rendering implementation should never do. 😁