Auto merge of #12986 - Veykril:completions, r=Veykril

Fix pattern field completions not working for unions

crates/ide-completion/src/completions.rs

@@ -617,7 +617,6 @@ pub(super) fn complete_name_ref(
 
                     dot::complete_undotted_self(acc, ctx, path_ctx, expr_ctx);
                     item_list::complete_item_list_in_expr(acc, ctx, path_ctx, expr_ctx);
-                    record::complete_record_expr_func_update(acc, ctx, path_ctx, expr_ctx);
                     snippet::complete_expr_snippet(acc, ctx, path_ctx, expr_ctx);
                 }
                 PathKind::Type { location } => {

crates/ide-completion/src/completions/expr.rs

@@ -1,8 +1,10 @@
 //! Completion of names from the current scope in expression position.
 
 use hir::ScopeDef;
+use syntax::ast;
 
 use crate::{
+    completions::record::add_default_update,
     context::{ExprCtx, PathCompletionCtx, Qualified},
     CompletionContext, Completions,
 };
@@ -219,9 +221,26 @@ pub(crate) fn complete_expr_path(
                 _ => (),
             });
 
-            if is_func_update.is_none() {
-                let mut add_keyword =
-                    |kw, snippet| acc.add_keyword_snippet_expr(ctx, incomplete_let, kw, snippet);
+            match is_func_update {
+                Some(record_expr) => {
+                    let ty = ctx.sema.type_of_expr(&ast::Expr::RecordExpr(record_expr.clone()));
+
+                    match ty.as_ref().and_then(|t| t.original.as_adt()) {
+                        Some(hir::Adt::Union(_)) => (),
+                        _ => {
+                            cov_mark::hit!(functional_update);
+                            let missing_fields =
+                                ctx.sema.record_literal_missing_fields(record_expr);
+                            if !missing_fields.is_empty() {
+                                add_default_update(acc, ctx, ty);
+                            }
+                        }
+                    };
+                }
+                None => {
+                    let mut add_keyword = |kw, snippet| {
+                        acc.add_keyword_snippet_expr(ctx, incomplete_let, kw, snippet)
+                    };
 
                     if !in_block_expr {
                         add_keyword("unsafe", "unsafe {\n    $0\n}");
@@ -277,4 +296,5 @@ pub(crate) fn complete_expr_path(
                 }
             }
         }
+    }
 }

crates/ide-completion/src/completions/record.rs

@@ -3,7 +3,7 @@
 use syntax::ast::{self, Expr};
 
 use crate::{
-    context::{DotAccess, DotAccessKind, ExprCtx, PathCompletionCtx, PatternContext, Qualified},
+    context::{DotAccess, DotAccessKind, PatternContext},
     CompletionContext, CompletionItem, CompletionItemKind, CompletionRelevance,
     CompletionRelevancePostfixMatch, Completions,
 };
@@ -14,7 +14,24 @@ pub(crate) fn complete_record_pattern_fields(
     pattern_ctx: &PatternContext,
 ) {
     if let PatternContext { record_pat: Some(record_pat), .. } = pattern_ctx {
-        complete_fields(acc, ctx, ctx.sema.record_pattern_missing_fields(record_pat));
+        let ty = ctx.sema.type_of_pat(&ast::Pat::RecordPat(record_pat.clone()));
+        let missing_fields = match ty.as_ref().and_then(|t| t.original.as_adt()) {
+            Some(hir::Adt::Union(un)) => {
+                // ctx.sema.record_pat_missing_fields will always return
+                // an empty Vec on a union literal. This is normally
+                // reasonable, but here we'd like to present the full list
+                // of fields if the literal is empty.
+                let were_fields_specified =
+                    record_pat.record_pat_field_list().and_then(|fl| fl.fields().next()).is_some();
+
+                match were_fields_specified {
+                    false => un.fields(ctx.db).into_iter().map(|f| (f, f.ty(ctx.db))).collect(),
+                    true => return,
+                }
+            }
+            _ => ctx.sema.record_pattern_missing_fields(record_pat),
+        };
+        complete_fields(acc, ctx, missing_fields);
     }
 }
 
@@ -42,8 +59,13 @@ pub(crate) fn complete_record_expr_fields(
         }
         _ => {
             let missing_fields = ctx.sema.record_literal_missing_fields(record_expr);
-            add_default_update(acc, ctx, ty, &missing_fields);
+
+            if !missing_fields.is_empty() {
+                cov_mark::hit!(functional_update_field);
+                add_default_update(acc, ctx, ty);
+            }
             if dot_prefix {
+                cov_mark::hit!(functional_update_one_dot);
                 let mut item =
                     CompletionItem::new(CompletionItemKind::Snippet, ctx.source_range(), "..");
                 item.insert_text(".");
@@ -56,41 +78,18 @@ pub(crate) fn complete_record_expr_fields(
     complete_fields(acc, ctx, missing_fields);
 }
 
-// FIXME: This should probably be part of complete_path_expr
-pub(crate) fn complete_record_expr_func_update(
-    acc: &mut Completions,
-    ctx: &CompletionContext<'_>,
-    path_ctx: &PathCompletionCtx,
-    expr_ctx: &ExprCtx,
-) {
-    if !matches!(path_ctx.qualified, Qualified::No) {
-        return;
-    }
-    if let ExprCtx { is_func_update: Some(record_expr), .. } = expr_ctx {
-        let ty = ctx.sema.type_of_expr(&Expr::RecordExpr(record_expr.clone()));
-
-        match ty.as_ref().and_then(|t| t.original.as_adt()) {
-            Some(hir::Adt::Union(_)) => (),
-            _ => {
-                let missing_fields = ctx.sema.record_literal_missing_fields(record_expr);
-                add_default_update(acc, ctx, ty, &missing_fields);
-            }
-        };
-    }
-}
-
-fn add_default_update(
+pub(crate) fn add_default_update(
     acc: &mut Completions,
     ctx: &CompletionContext<'_>,
     ty: Option<hir::TypeInfo>,
-    missing_fields: &[(hir::Field, hir::Type)],
 ) {
     let default_trait = ctx.famous_defs().core_default_Default();
-    let impl_default_trait = default_trait
+    let impls_default_trait = default_trait
         .zip(ty.as_ref())
         .map_or(false, |(default_trait, ty)| ty.original.impls_trait(ctx.db, default_trait, &[]));
-    if impl_default_trait && !missing_fields.is_empty() {
+    if impls_default_trait {
         // FIXME: This should make use of scope_def like completions so we get all the other goodies
+        // that is we should handle this like actually completing the default function
         let completion_text = "..Default::default()";
         let mut item = CompletionItem::new(SymbolKind::Field, ctx.source_range(), completion_text);
         let completion_text =

crates/ide-completion/src/context.rs

@@ -134,6 +134,7 @@ pub(crate) struct ExprCtx {
     pub(crate) in_condition: bool,
     pub(crate) incomplete_let: bool,
     pub(crate) ref_expr_parent: Option<ast::RefExpr>,
+    /// The surrounding RecordExpression we are completing a functional update
     pub(crate) is_func_update: Option<ast::RecordExpr>,
     pub(crate) self_param: Option<hir::SelfParam>,
     pub(crate) innermost_ret_ty: Option<hir::Type>,

crates/ide-completion/src/tests/record.rs

@@ -103,47 +103,9 @@ fn foo(f: Struct) {
 }
 
 #[test]
-fn functional_update() {
-    // FIXME: This should filter out all completions that do not have the type `Foo`
-    check(
-        r#"
-//- minicore:default
-struct Foo { foo1: u32, foo2: u32 }
-impl Default for Foo {
-    fn default() -> Self { loop {} }
-}
+fn in_functional_update() {
+    cov_mark::check!(functional_update);
 
-fn main() {
-    let thing = 1;
-    let foo = Foo { foo1: 0, foo2: 0 };
-    let foo2 = Foo { thing, $0 }
-}
-"#,
-        expect![[r#"
-            fd ..Default::default()
-            fd foo1                 u32
-            fd foo2                 u32
-        "#]],
-    );
-    check(
-        r#"
-//- minicore:default
-struct Foo { foo1: u32, foo2: u32 }
-impl Default for Foo {
-    fn default() -> Self { loop {} }
-}
-
-fn main() {
-    let thing = 1;
-    let foo = Foo { foo1: 0, foo2: 0 };
-    let foo2 = Foo { thing, .$0 }
-}
-"#,
-        expect![[r#"
-            fd ..Default::default()
-            sn ..
-        "#]],
-    );
     check(
         r#"
 //- minicore:default
@@ -192,6 +154,56 @@ fn default() (as Default) fn() -> Self
     );
 }
 
+#[test]
+fn functional_update_no_dot() {
+    cov_mark::check!(functional_update_field);
+    // FIXME: This should filter out all completions that do not have the type `Foo`
+    check(
+        r#"
+//- minicore:default
+struct Foo { foo1: u32, foo2: u32 }
+impl Default for Foo {
+    fn default() -> Self { loop {} }
+}
+
+fn main() {
+    let thing = 1;
+    let foo = Foo { foo1: 0, foo2: 0 };
+    let foo2 = Foo { thing, $0 }
+}
+"#,
+        expect![[r#"
+            fd ..Default::default()
+            fd foo1                 u32
+            fd foo2                 u32
+        "#]],
+    );
+}
+
+#[test]
+fn functional_update_one_dot() {
+    cov_mark::check!(functional_update_one_dot);
+    check(
+        r#"
+//- minicore:default
+struct Foo { foo1: u32, foo2: u32 }
+impl Default for Foo {
+    fn default() -> Self { loop {} }
+}
+
+fn main() {
+    let thing = 1;
+    let foo = Foo { foo1: 0, foo2: 0 };
+    let foo2 = Foo { thing, .$0 }
+}
+"#,
+        expect![[r#"
+            fd ..Default::default()
+            sn ..
+        "#]],
+    );
+}
+
 #[test]
 fn empty_union_literal() {
     check(