complete struct literals

1 files changed, 64 insertions, 0 deletions

diff --git a/crates/ra_ide_api/src/completion/complete_struct_literal.rs b/crates/ra_ide_api/src/completion/complete_struct_literal.rs
new file mode 100644
index 000000000..893056c2b
--- /dev/null
+++ b/crates/ra_ide_api/src/completion/complete_struct_literal.rs
@@ -0,0 +1,64 @@
+use hir::{Ty, AdtDef, Docs};
+
+use crate::completion::{CompletionContext, Completions, CompletionItem, CompletionItemKind};
+use crate::completion::completion_item::CompletionKind;
+
+/// Complete dot accesses, i.e. fields or methods (currently only fields).
+pub(super) fn complete_struct_literal(acc: &mut Completions, ctx: &CompletionContext) {
+    let (function, struct_lit) = match (&ctx.function, ctx.struct_lit_syntax) {
+        (Some(function), Some(struct_lit)) => (function, struct_lit),
+        _ => return,
+    };
+    let infer_result = function.infer(ctx.db);
+    let syntax_mapping = function.body_syntax_mapping(ctx.db);
+    let expr = match syntax_mapping.node_expr(struct_lit.into()) {
+        Some(expr) => expr,
+        None => return,
+    };
+    let ty = infer_result[expr].clone();
+    let (adt, substs) = match ty {
+        Ty::Adt { def_id, ref substs, .. } => (def_id, substs),
+        _ => return,
+    };
+    match adt {
+        AdtDef::Struct(s) => {
+            for field in s.fields(ctx.db) {
+                CompletionItem::new(
+                    CompletionKind::Reference,
+                    ctx.source_range(),
+                    field.name(ctx.db).to_string(),
+                )
+                .kind(CompletionItemKind::Field)
+                .detail(field.ty(ctx.db).subst(substs).to_string())
+                .set_documentation(field.docs(ctx.db))
+                .add_to(acc);
+            }
+        }
+
+        // TODO unions
+        AdtDef::Enum(_) => (),
+    };
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::completion::*;
+    use crate::completion::completion_item::check_completion;
+
+    fn check_ref_completion(name: &str, code: &str) {
+        check_completion(name, code, CompletionKind::Reference);
+    }
+
+    #[test]
+    fn test_struct_literal_field() {
+        check_ref_completion(
+            "test_struct_literal_field",
+            r"
+            struct A { the_field: u32 }
+            fn foo() {
+               A { the<|> }
+            }
+            ",
+        );
+    }
+}