add record pat missing field diagnostic

4 files changed, 149 insertions, 28 deletions

diff --git a/crates/ra_hir_ty/src/diagnostics.rs b/crates/ra_hir_ty/src/diagnostics.rs
index 8cbce1168..3f18acf1d 100644
--- a/crates/ra_hir_ty/src/diagnostics.rs
+++ b/crates/ra_hir_ty/src/diagnostics.rs
@@ -63,6 +63,29 @@ impl AstDiagnostic for MissingFields {
 }
 
 #[derive(Debug)]
+pub struct MissingPatFields {
+    pub file: HirFileId,
+    pub field_list: AstPtr<ast::RecordFieldPatList>,
+    pub missed_fields: Vec<Name>,
+}
+
+impl Diagnostic for MissingPatFields {
+    fn message(&self) -> String {
+        let mut buf = String::from("Missing structure fields:\n");
+        for field in &self.missed_fields {
+            format_to!(buf, "- {}", field);
+        }
+        buf
+    }
+    fn source(&self) -> InFile<SyntaxNodePtr> {
+        InFile { file_id: self.file, value: self.field_list.into() }
+    }
+    fn as_any(&self) -> &(dyn Any + Send + 'static) {
+        self
+    }
+}
+
+#[derive(Debug)]
 pub struct MissingMatchArms {
     pub file: HirFileId,
     pub match_expr: AstPtr<ast::Expr>,
diff --git a/crates/ra_hir_ty/src/expr.rs b/crates/ra_hir_ty/src/expr.rs
index e45e9ea14..a7c8d74ab 100644
--- a/crates/ra_hir_ty/src/expr.rs
+++ b/crates/ra_hir_ty/src/expr.rs
@@ -9,7 +9,7 @@ use rustc_hash::FxHashSet;
 
 use crate::{
     db::HirDatabase,
-    diagnostics::{MissingFields, MissingMatchArms, MissingOkInTailExpr},
+    diagnostics::{MissingFields, MissingMatchArms, MissingOkInTailExpr, MissingPatFields},
     utils::variant_data,
     ApplicationTy, InferenceResult, Ty, TypeCtor,
     _match::{is_useful, MatchCheckCtx, Matrix, PatStack, Usefulness},
@@ -49,39 +49,97 @@ impl<'a, 'b> ExprValidator<'a, 'b> {
             if let Some((variant_def, missed_fields, true)) =
                 record_literal_missing_fields(db, &self.infer, id, expr)
             {
-                // XXX: only look at source_map if we do have missing fields
-                let (_, source_map) = db.body_with_source_map(self.func.into());
-
-                if let Ok(source_ptr) = source_map.expr_syntax(id) {
-                    if let Some(expr) = source_ptr.value.left() {
-                        let root = source_ptr.file_syntax(db.upcast());
-                        if let ast::Expr::RecordLit(record_lit) = expr.to_node(&root) {
-                            if let Some(field_list) = record_lit.record_field_list() {
-                                let variant_data = variant_data(db.upcast(), variant_def);
-                                let missed_fields = missed_fields
-                                    .into_iter()
-                                    .map(|idx| variant_data.fields()[idx].name.clone())
-                                    .collect();
-                                self.sink.push(MissingFields {
-                                    file: source_ptr.file_id,
-                                    field_list: AstPtr::new(&field_list),
-                                    missed_fields,
-                                })
-                            }
-                        }
-                    }
-                }
+                self.create_record_literal_missing_fields_diagnostic(
+                    id,
+                    db,
+                    variant_def,
+                    missed_fields,
+                );
             }
             if let Expr::Match { expr, arms } = expr {
                 self.validate_match(id, *expr, arms, db, self.infer.clone());
             }
         }
+        for (id, pat) in body.pats.iter() {
+            if let Some((variant_def, missed_fields, true)) =
+                record_pattern_missing_fields(db, &self.infer, id, pat)
+            {
+                self.create_record_pattern_missing_fields_diagnostic(
+                    id,
+                    db,
+                    variant_def,
+                    missed_fields,
+                );
+            }
+        }
         let body_expr = &body[body.body_expr];
         if let Expr::Block { tail: Some(t), .. } = body_expr {
             self.validate_results_in_tail_expr(body.body_expr, *t, db);
         }
     }
 
+    fn create_record_literal_missing_fields_diagnostic(
+        &mut self,
+        id: ExprId,
+        db: &dyn HirDatabase,
+        variant_def: VariantId,
+        missed_fields: Vec<LocalStructFieldId>,
+    ) {
+        // XXX: only look at source_map if we do have missing fields
+        let (_, source_map) = db.body_with_source_map(self.func.into());
+
+        if let Ok(source_ptr) = source_map.expr_syntax(id) {
+            if let Some(expr) = source_ptr.value.left() {
+                let root = source_ptr.file_syntax(db.upcast());
+                if let ast::Expr::RecordLit(record_lit) = expr.to_node(&root) {
+                    if let Some(field_list) = record_lit.record_field_list() {
+                        let variant_data = variant_data(db.upcast(), variant_def);
+                        let missed_fields = missed_fields
+                            .into_iter()
+                            .map(|idx| variant_data.fields()[idx].name.clone())
+                            .collect();
+                        self.sink.push(MissingFields {
+                            file: source_ptr.file_id,
+                            field_list: AstPtr::new(&field_list),
+                            missed_fields,
+                        })
+                    }
+                }
+            }
+        }
+    }
+
+    fn create_record_pattern_missing_fields_diagnostic(
+        &mut self,
+        id: PatId,
+        db: &dyn HirDatabase,
+        variant_def: VariantId,
+        missed_fields: Vec<LocalStructFieldId>,
+    ) {
+        // XXX: only look at source_map if we do have missing fields
+        let (_, source_map) = db.body_with_source_map(self.func.into());
+
+        if let Ok(source_ptr) = source_map.pat_syntax(id) {
+            if let Some(expr) = source_ptr.value.left() {
+                let root = source_ptr.file_syntax(db.upcast());
+                if let ast::Pat::RecordPat(record_pat) = expr.to_node(&root) {
+                    if let Some(field_list) = record_pat.record_field_pat_list() {
+                        let variant_data = variant_data(db.upcast(), variant_def);
+                        let missed_fields = missed_fields
+                            .into_iter()
+                            .map(|idx| variant_data.fields()[idx].name.clone())
+                            .collect();
+                        self.sink.push(MissingPatFields {
+                            file: source_ptr.file_id,
+                            field_list: AstPtr::new(&field_list),
+                            missed_fields,
+                        })
+                    }
+                }
+            }
+        }
+    }
+
     fn validate_match(
         &mut self,
         id: ExprId,
@@ -232,9 +290,9 @@ pub fn record_pattern_missing_fields(
     infer: &InferenceResult,
     id: PatId,
     pat: &Pat,
-) -> Option<(VariantId, Vec<LocalStructFieldId>)> {
-    let fields = match pat {
-        Pat::Record { path: _, args } => args,
+) -> Option<(VariantId, Vec<LocalStructFieldId>, /*exhaustive*/ bool)> {
+    let (fields, exhaustive) = match pat {
+        Pat::Record { path: _, args, ellipsis } => (args, !ellipsis),
         _ => return None,
     };
 
@@ -254,5 +312,5 @@ pub fn record_pattern_missing_fields(
     if missed_fields.is_empty() {
         return None;
     }
-    Some((variant_def, missed_fields))
+    Some((variant_def, missed_fields, exhaustive))
 }
diff --git a/crates/ra_hir_ty/src/infer/pat.rs b/crates/ra_hir_ty/src/infer/pat.rs
index 69bbb4307..078476f76 100644
--- a/crates/ra_hir_ty/src/infer/pat.rs
+++ b/crates/ra_hir_ty/src/infer/pat.rs
@@ -158,7 +158,7 @@ impl<'a> InferenceContext<'a> {
             Pat::TupleStruct { path: p, args: subpats } => {
                 self.infer_tuple_struct_pat(p.as_ref(), subpats, expected, default_bm, pat)
             }
-            Pat::Record { path: p, args: fields } => {
+            Pat::Record { path: p, args: fields, ellipsis: _ } => {
                 self.infer_record_pat(p.as_ref(), fields, expected, default_bm, pat)
             }
             Pat::Path(path) => {
diff --git a/crates/ra_hir_ty/src/tests.rs b/crates/ra_hir_ty/src/tests.rs
index 002cffba6..47a7b9ffd 100644
--- a/crates/ra_hir_ty/src/tests.rs
+++ b/crates/ra_hir_ty/src/tests.rs
@@ -409,3 +409,43 @@ fn no_such_field_with_feature_flag_diagnostics_on_struct_fields() {
 
     assert_snapshot!(diagnostics, @r###""###);
 }
+
+#[test]
+fn missing_record_pat_field_diagnostic() {
+    let diagnostics = TestDB::with_files(
+        r"
+        //- /lib.rs
+        struct S { foo: i32, bar: () }
+        fn baz(s: S) {
+            let S { foo: _ } = s;
+        }
+        ",
+    )
+    .diagnostics()
+    .0;
+
+    assert_snapshot!(diagnostics, @r###"
+    "{ foo: _ }": Missing structure fields:
+    - bar
+    "###
+    );
+}
+
+#[test]
+fn missing_record_pat_field_no_diagnostic_if_not_exhaustive() {
+    let diagnostics = TestDB::with_files(
+        r"
+        //- /lib.rs
+        struct S { foo: i32, bar: () }
+        fn baz(s: S) -> i32 {
+            match s {
+                S { foo, .. } => foo,
+            }
+        }
+        ",
+    )
+    .diagnostics()
+    .0;
+
+    assert_snapshot!(diagnostics, @"");
+}