1 files changed, 92 insertions, 0 deletions

diff --git a/crates/ra_hir/src/expr/validation.rs b/crates/ra_hir/src/expr/validation.rs
new file mode 100644
index 000000000..fd4907313
--- /dev/null
+++ b/crates/ra_hir/src/expr/validation.rs
@@ -0,0 +1,92 @@
+use std::sync::Arc;
+use rustc_hash::FxHashSet;
+
+use ra_syntax::ast::{AstNode, StructLit};
+
+use crate::{
+    expr::AstPtr,
+    HirDatabase,
+    Function,
+    Name,
+    diagnostics::{DiagnosticSink, MissingFields},
+    adt::AdtDef,
+    Path,
+    ty::InferenceResult
+};
+use super::{Expr, StructLitField, ExprId};
+
+pub(crate) struct ExprValidator<'a, 'b: 'a> {
+    func: Function,
+    infer: Arc<InferenceResult>,
+    sink: &'a mut DiagnosticSink<'b>,
+}
+
+impl<'a, 'b> ExprValidator<'a, 'b> {
+    pub(crate) fn new(
+        func: Function,
+        infer: Arc<InferenceResult>,
+        sink: &'a mut DiagnosticSink<'b>,
+    ) -> ExprValidator<'a, 'b> {
+        ExprValidator { func, infer, sink }
+    }
+
+    pub(crate) fn validate_body(&mut self, db: &impl HirDatabase) {
+        let body = self.func.body(db);
+        for e in body.exprs() {
+            match e {
+                (id, Expr::StructLit { path, fields, spread }) => {
+                    self.validate_struct_literal(id, path, fields, spread, db)
+                }
+                _ => (),
+            }
+        }
+    }
+
+    fn validate_struct_literal(
+        &mut self,
+        id: ExprId,
+        _path: &Option<Path>,
+        fields: &Vec<StructLitField>,
+        spread: &Option<ExprId>,
+        db: &impl HirDatabase,
+    ) {
+        if let Some(_) = spread {
+            return;
+        }
+        let lit_fields: FxHashSet<_> = fields.into_iter().map(|f| &f.name).collect();
+        let struct_ty = &self.infer[id];
+        if let Some((AdtDef::Struct(s), _)) = struct_ty.as_adt() {
+            let missed_fields: Vec<Name> = s
+                .fields(db)
+                .iter()
+                .filter_map(|f| {
+                    let name = f.name(db);
+                    if lit_fields.contains(&name) {
+                        None
+                    } else {
+                        Some(name)
+                    }
+                })
+                .collect();
+            if missed_fields.is_empty() {
+                return;
+            }
+            let source_map = self.func.body_source_map(db);
+            let file_id = self.func.source(db).0;
+            let source_file = db.parse(file_id.original_file(db));
+            if let Some(field_list_node) = source_map
+                .expr_syntax(id)
+                .map(|ptr| ptr.to_node(&source_file))
+                .and_then(StructLit::cast)
+                .and_then(|lit| lit.named_field_list())
+            {
+                let field_list_ptr = AstPtr::new(field_list_node);
+                self.sink.push(MissingFields {
+                    file: file_id,
+                    field_list: field_list_ptr,
+                    missed_fields,
+                })
+            }
+        }
+    }
+}