1 files changed, 203 insertions, 0 deletions

diff --git a/crates/ide_diagnostics/src/handlers/field_shorthand.rs b/crates/ide_diagnostics/src/handlers/field_shorthand.rs
new file mode 100644
index 000000000..33152e284
--- /dev/null
+++ b/crates/ide_diagnostics/src/handlers/field_shorthand.rs
@@ -0,0 +1,203 @@
+//! Suggests shortening `Foo { field: field }` to `Foo { field }` in both
+//! expressions and patterns.
+
+use ide_db::{base_db::FileId, source_change::SourceChange};
+use syntax::{ast, match_ast, AstNode, SyntaxNode};
+use text_edit::TextEdit;
+
+use crate::{fix, Diagnostic, Severity};
+
+pub(crate) fn field_shorthand(acc: &mut Vec<Diagnostic>, file_id: FileId, node: &SyntaxNode) {
+    match_ast! {
+        match node {
+            ast::RecordExpr(it) => check_expr_field_shorthand(acc, file_id, it),
+            ast::RecordPat(it) => check_pat_field_shorthand(acc, file_id, it),
+            _ => ()
+        }
+    };
+}
+
+fn check_expr_field_shorthand(
+    acc: &mut Vec<Diagnostic>,
+    file_id: FileId,
+    record_expr: ast::RecordExpr,
+) {
+    let record_field_list = match record_expr.record_expr_field_list() {
+        Some(it) => it,
+        None => return,
+    };
+    for record_field in record_field_list.fields() {
+        let (name_ref, expr) = match record_field.name_ref().zip(record_field.expr()) {
+            Some(it) => it,
+            None => continue,
+        };
+
+        let field_name = name_ref.syntax().text().to_string();
+        let field_expr = expr.syntax().text().to_string();
+        let field_name_is_tup_index = name_ref.as_tuple_field().is_some();
+        if field_name != field_expr || field_name_is_tup_index {
+            continue;
+        }
+
+        let mut edit_builder = TextEdit::builder();
+        edit_builder.delete(record_field.syntax().text_range());
+        edit_builder.insert(record_field.syntax().text_range().start(), field_name);
+        let edit = edit_builder.finish();
+
+        let field_range = record_field.syntax().text_range();
+        acc.push(
+            Diagnostic::new("use-field-shorthand", "Shorthand struct initialization", field_range)
+                .severity(Severity::WeakWarning)
+                .with_fixes(Some(vec![fix(
+                    "use_expr_field_shorthand",
+                    "Use struct shorthand initialization",
+                    SourceChange::from_text_edit(file_id, edit),
+                    field_range,
+                )])),
+        );
+    }
+}
+
+fn check_pat_field_shorthand(
+    acc: &mut Vec<Diagnostic>,
+    file_id: FileId,
+    record_pat: ast::RecordPat,
+) {
+    let record_pat_field_list = match record_pat.record_pat_field_list() {
+        Some(it) => it,
+        None => return,
+    };
+    for record_pat_field in record_pat_field_list.fields() {
+        let (name_ref, pat) = match record_pat_field.name_ref().zip(record_pat_field.pat()) {
+            Some(it) => it,
+            None => continue,
+        };
+
+        let field_name = name_ref.syntax().text().to_string();
+        let field_pat = pat.syntax().text().to_string();
+        let field_name_is_tup_index = name_ref.as_tuple_field().is_some();
+        if field_name != field_pat || field_name_is_tup_index {
+            continue;
+        }
+
+        let mut edit_builder = TextEdit::builder();
+        edit_builder.delete(record_pat_field.syntax().text_range());
+        edit_builder.insert(record_pat_field.syntax().text_range().start(), field_name);
+        let edit = edit_builder.finish();
+
+        let field_range = record_pat_field.syntax().text_range();
+        acc.push(
+            Diagnostic::new("use-field-shorthand", "Shorthand struct pattern", field_range)
+                .severity(Severity::WeakWarning)
+                .with_fixes(Some(vec![fix(
+                    "use_pat_field_shorthand",
+                    "Use struct field shorthand",
+                    SourceChange::from_text_edit(file_id, edit),
+                    field_range,
+                )])),
+        );
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_diagnostics, check_fix};
+
+    #[test]
+    fn test_check_expr_field_shorthand() {
+        check_diagnostics(
+            r#"
+struct A { a: &'static str }
+fn main() { A { a: "hello" } }
+"#,
+        );
+        check_diagnostics(
+            r#"
+struct A(usize);
+fn main() { A { 0: 0 } }
+"#,
+        );
+
+        check_fix(
+            r#"
+struct A { a: &'static str }
+fn main() {
+    let a = "haha";
+    A { a$0: a }
+}
+"#,
+            r#"
+struct A { a: &'static str }
+fn main() {
+    let a = "haha";
+    A { a }
+}
+"#,
+        );
+
+        check_fix(
+            r#"
+struct A { a: &'static str, b: &'static str }
+fn main() {
+    let a = "haha";
+    let b = "bb";
+    A { a$0: a, b }
+}
+"#,
+            r#"
+struct A { a: &'static str, b: &'static str }
+fn main() {
+    let a = "haha";
+    let b = "bb";
+    A { a, b }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn test_check_pat_field_shorthand() {
+        check_diagnostics(
+            r#"
+struct A { a: &'static str }
+fn f(a: A) { let A { a: hello } = a; }
+"#,
+        );
+        check_diagnostics(
+            r#"
+struct A(usize);
+fn f(a: A) { let A { 0: 0 } = a; }
+"#,
+        );
+
+        check_fix(
+            r#"
+struct A { a: &'static str }
+fn f(a: A) {
+    let A { a$0: a } = a;
+}
+"#,
+            r#"
+struct A { a: &'static str }
+fn f(a: A) {
+    let A { a } = a;
+}
+"#,
+        );
+
+        check_fix(
+            r#"
+struct A { a: &'static str, b: &'static str }
+fn f(a: A) {
+    let A { a$0: a, b } = a;
+}
+"#,
+            r#"
+struct A { a: &'static str, b: &'static str }
+fn f(a: A) {
+    let A { a, b } = a;
+}
+"#,
+        );
+    }
+}