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|
use std::fmt::Write;
use hir::{
AdtDef,
source_binder,
Ty,
FieldSource,
};
use ra_ide_api_light::{
assists::{
Assist,
AssistBuilder
}
};
use ra_syntax::{
ast::{
self,
AstNode,
}
};
use crate::assits::AssistCtx;
pub fn fill_match_arm(ctx: AssistCtx) -> Option<Assist> {
let match_expr = ctx.node_at_offset::<ast::MatchExpr>()?;
// We already have some match arms, so we don't provide any assists.
match match_expr.match_arm_list() {
Some(arm_list) if arm_list.arms().count() > 0 => {
return None;
}
_ => {}
}
let expr = match_expr.expr()?;
let function = source_binder::function_from_child_node(ctx.db, ctx.file_id, expr.syntax())?;
let infer_result = function.infer(ctx.db);
let syntax_mapping = function.body_syntax_mapping(ctx.db);
let node_expr = syntax_mapping.node_expr(expr)?;
let match_expr_ty = infer_result[node_expr].clone();
match match_expr_ty {
Ty::Adt { def_id, .. } => match def_id {
AdtDef::Enum(e) => {
let mut buf = format!("match {} {{\n", expr.syntax().text().to_string());
let variants = e.variants(ctx.db);
for variant in variants {
let name = variant.name(ctx.db)?;
write!(
&mut buf,
" {}::{}",
e.name(ctx.db)?.to_string(),
name.to_string()
)
.expect("write fmt");
let pat = variant
.fields(ctx.db)
.into_iter()
.map(|field| {
let name = field.name(ctx.db).to_string();
let (_, source) = field.source(ctx.db);
match source {
FieldSource::Named(_) => name,
FieldSource::Pos(_) => "_".to_string(),
}
})
.collect::<Vec<_>>();
match pat.first().map(|s| s.as_str()) {
Some("_") => write!(&mut buf, "({})", pat.join(", ")).expect("write fmt"),
Some(_) => write!(&mut buf, "{{{}}}", pat.join(", ")).expect("write fmt"),
None => (),
};
buf.push_str(" => (),\n");
}
buf.push_str("}");
ctx.build("fill match arms", |edit: &mut AssistBuilder| {
edit.replace_node_and_indent(match_expr.syntax(), buf);
})
}
_ => None,
},
_ => None,
}
}
#[cfg(test)]
mod tests {
use insta::assert_debug_snapshot_matches;
use ra_syntax::{TextRange, TextUnit};
use crate::{
FileRange,
mock_analysis::{analysis_and_position, single_file_with_position}
};
use ra_db::SourceDatabase;
fn test_assit(name: &str, code: &str) {
let (analysis, position) = if code.contains("//-") {
analysis_and_position(code)
} else {
single_file_with_position(code)
};
let frange = FileRange {
file_id: position.file_id,
range: TextRange::offset_len(position.offset, TextUnit::from(1)),
};
let source_file = analysis
.with_db(|db| db.parse(frange.file_id))
.expect("source file");
let ret = analysis
.with_db(|db| crate::assits::assists(db, frange.file_id, &source_file, frange.range))
.expect("assits");
assert_debug_snapshot_matches!(name, ret);
}
#[test]
fn test_fill_match_arm() {
test_assit(
"fill_match_arm1",
r#"
enum A {
As,
Bs,
Cs(String),
Ds(String, String),
Es{x: usize, y: usize}
}
fn main() {
let a = A::As;
match a<|>
}
"#,
);
test_assit(
"fill_match_arm2",
r#"
enum A {
As,
Bs,
Cs(String),
Ds(String, String),
Es{x: usize, y: usize}
}
fn main() {
let a = A::As;
match a<|> {}
}
"#,
);
}
}
|
