diff --git a/internal/lsp/completion_test.go b/internal/lsp/completion_test.go
index 6fdffa1fb1..664e075901 100644
--- a/internal/lsp/completion_test.go
+++ b/internal/lsp/completion_test.go
@@ -49,7 +49,7 @@ func (r *runner) UnimportedCompletion(t *testing.T, src span.Span, test tests.Co
 		got = tests.FilterBuiltins(got)
 	}
 	want := expected(t, test, items)
-	if diff := tests.CheckCompletionOrder(want, got); diff != "" {
+	if diff := tests.CheckCompletionOrder(want, got, false); diff != "" {
 		t.Errorf("%s: %s", src, diff)
 	}
 }
@@ -101,7 +101,7 @@ func (r *runner) RankCompletion(t *testing.T, src span.Span, test tests.Completi
 		Deep:          true,
 	})
 	want := expected(t, test, items)
-	if msg := tests.CheckCompletionOrder(want, got); msg != "" {
+	if msg := tests.CheckCompletionOrder(want, got, true); msg != "" {
 		t.Errorf("%s: %s", src, msg)
 	}
 }
diff --git a/internal/lsp/source/completion.go b/internal/lsp/source/completion.go
index 82230c9a0f..de26587c67 100644
--- a/internal/lsp/source/completion.go
+++ b/internal/lsp/source/completion.go
@@ -1462,8 +1462,8 @@ func (c *completer) matchingCandidate(cand *candidate) bool {
 		return false
 	}
 
-	objType := cand.obj.Type()
-	if objType == nil {
+	candType := cand.obj.Type()
+	if candType == nil {
 		return true
 	}
 
@@ -1472,17 +1472,20 @@ func (c *completer) matchingCandidate(cand *candidate) bool {
 	// are invoked by default.
 	cand.expandFuncCall = isFunc(cand.obj)
 
-	typeMatches := func(candType types.Type) bool {
+	typeMatches := func(expType, candType types.Type) bool {
+		if expType == nil {
+			return false
+		}
+
 		// Take into account any type modifiers on the expected type.
 		candType = c.expectedType.applyTypeModifiers(candType)
 
-		if c.expectedType.objType != nil {
-			wantType := types.Default(c.expectedType.objType)
-
-			// Handle untyped values specially since AssignableTo gives false negatives
-			// for them (see https://golang.org/issue/32146).
-			if candBasic, ok := candType.(*types.Basic); ok && candBasic.Info()&types.IsUntyped > 0 {
-				if wantBasic, ok := wantType.Underlying().(*types.Basic); ok {
+		// Handle untyped values specially since AssignableTo gives false negatives
+		// for them (see https://golang.org/issue/32146).
+		if candBasic, ok := candType.Underlying().(*types.Basic); ok {
+			if wantBasic, ok := expType.Underlying().(*types.Basic); ok {
+				// Make sure at least one of them is untyped.
+				if isUntyped(candType) || isUntyped(expType) {
 					// Check that their constant kind (bool|int|float|complex|string) matches.
 					// This doesn't take into account the constant value, so there will be some
 					// false positives due to integer sign and overflow.
@@ -1490,32 +1493,29 @@ func (c *completer) matchingCandidate(cand *candidate) bool {
 						// Lower candidate score if the types are not identical.
 						// This avoids ranking untyped integer constants above
 						// candidates with an exact type match.
-						if !types.Identical(candType, c.expectedType.objType) {
+						if !types.Identical(candType, expType) {
 							cand.score /= 2
 						}
 						return true
 					}
 				}
-				return false
 			}
-
-			// AssignableTo covers the case where the types are equal, but also handles
-			// cases like assigning a concrete type to an interface type.
-			return types.AssignableTo(candType, wantType)
 		}
 
-		return false
+		// AssignableTo covers the case where the types are equal, but also handles
+		// cases like assigning a concrete type to an interface type.
+		return types.AssignableTo(candType, expType)
 	}
 
-	if typeMatches(objType) {
+	if typeMatches(c.expectedType.objType, candType) {
 		// If obj's type matches, we don't want to expand to an invocation of obj.
 		cand.expandFuncCall = false
 		return true
 	}
 
 	// Try using a function's return type as its type.
-	if sig, ok := objType.Underlying().(*types.Signature); ok && sig.Results().Len() == 1 {
-		if typeMatches(sig.Results().At(0).Type()) {
+	if sig, ok := candType.Underlying().(*types.Signature); ok && sig.Results().Len() == 1 {
+		if typeMatches(c.expectedType.objType, sig.Results().At(0).Type()) {
 			// If obj's return value matches the expected type, we need to invoke obj
 			// in the completion.
 			cand.expandFuncCall = true
@@ -1523,15 +1523,16 @@ func (c *completer) matchingCandidate(cand *candidate) bool {
 		}
 	}
 
-	// When completing the variadic parameter, say objType matches if
-	// []objType matches. This is because you can use []T or T for the
-	// variadic parameter.
-	if c.expectedType.variadic && typeMatches(types.NewSlice(objType)) {
-		return true
+	// When completing the variadic parameter, if the expected type is
+	// []T then check candType against T.
+	if c.expectedType.variadic {
+		if slice, ok := c.expectedType.objType.(*types.Slice); ok && typeMatches(slice.Elem(), candType) {
+			return true
+		}
 	}
 
 	if c.expectedType.convertibleTo != nil {
-		return types.ConvertibleTo(objType, c.expectedType.convertibleTo)
+		return types.ConvertibleTo(candType, c.expectedType.convertibleTo)
 	}
 
 	return false
diff --git a/internal/lsp/source/source_test.go b/internal/lsp/source/source_test.go
index 3ed53a50d0..2e2b0fd81c 100644
--- a/internal/lsp/source/source_test.go
+++ b/internal/lsp/source/source_test.go
@@ -138,7 +138,7 @@ func (r *runner) UnimportedCompletion(t *testing.T, src span.Span, test tests.Co
 	if !strings.Contains(string(src.URI()), "builtins") {
 		got = tests.FilterBuiltins(got)
 	}
-	if diff := tests.CheckCompletionOrder(want, got); diff != "" {
+	if diff := tests.CheckCompletionOrder(want, got, false); diff != "" {
 		t.Errorf("%s: %s", src, diff)
 	}
 }
@@ -229,7 +229,7 @@ func (r *runner) RankCompletion(t *testing.T, src span.Span, test tests.Completi
 		}
 		got = append(got, item)
 	}
-	if msg := tests.CheckCompletionOrder(want, got); msg != "" {
+	if msg := tests.CheckCompletionOrder(want, got, true); msg != "" {
 		t.Errorf("%s: %s", src, msg)
 	}
 }
diff --git a/internal/lsp/source/util.go b/internal/lsp/source/util.go
index 4e7138592b..68df3fb7fb 100644
--- a/internal/lsp/source/util.go
+++ b/internal/lsp/source/util.go
@@ -330,6 +330,13 @@ func isEmptyInterface(T types.Type) bool {
 	return intf != nil && intf.NumMethods() == 0
 }
 
+func isUntyped(T types.Type) bool {
+	if basic, ok := T.(*types.Basic); ok {
+		return basic.Info()&types.IsUntyped > 0
+	}
+	return false
+}
+
 // isSelector returns the enclosing *ast.SelectorExpr when pos is in the
 // selector.
 func enclosingSelector(path []ast.Node, pos token.Pos) *ast.SelectorExpr {
diff --git a/internal/lsp/testdata/deep/deep.go b/internal/lsp/testdata/deep/deep.go
index df70c14725..1bedc9416c 100644
--- a/internal/lsp/testdata/deep/deep.go
+++ b/internal/lsp/testdata/deep/deep.go
@@ -29,7 +29,7 @@ func _() {
 	context.Background() //@item(ctxBackground, "context.Background", "func() context.Context", "func", "Background returns a non-nil, empty Context.")
 	context.TODO()       //@item(ctxTODO, "context.TODO", "func() context.Context", "func", "TODO returns a non-nil, empty Context.")
 
-	wantsContext(c) //@rank(")", ctxBackground, ctxTODO)
+	wantsContext(c) //@rank(")", ctxBackground),rank(")", ctxTODO)
 }
 
 func _() {
diff --git a/internal/lsp/testdata/rank/convert_rank.go.in b/internal/lsp/testdata/rank/convert_rank.go.in
index ac17416260..77e2d27d0a 100644
--- a/internal/lsp/testdata/rank/convert_rank.go.in
+++ b/internal/lsp/testdata/rank/convert_rank.go.in
@@ -30,7 +30,7 @@ func _() {
 	mi = conv //@rank(" //", convertG, convertD, convertE)
 	mi + conv //@rank(" //", convertG, convertD, convertE)
 
-	1 + conv //@rank(" //", convertD, convertE, convertG)
+	1 + conv //@rank(" //", convertD, convertC),rank(" //", convertE, convertC),rank(" //", convertG, convertC)
 
 	type myString string
 	var ms myString
diff --git a/internal/lsp/testdata/summary.txt.golden b/internal/lsp/testdata/summary.txt.golden
index 19e9ad33cd..682605b004 100644
--- a/internal/lsp/testdata/summary.txt.golden
+++ b/internal/lsp/testdata/summary.txt.golden
@@ -4,7 +4,7 @@ CompletionSnippetCount = 47
 UnimportedCompletionsCount = 3
 DeepCompletionsCount = 5
 FuzzyCompletionsCount = 7
-RankedCompletionsCount = 22
+RankedCompletionsCount = 26
 CaseSensitiveCompletionsCount = 4
 DiagnosticsCount = 22
 FoldingRangesCount = 2
diff --git a/internal/lsp/testdata/variadic/variadic.go.in b/internal/lsp/testdata/variadic/variadic.go.in
index 76e3a56655..8a7fa241fe 100644
--- a/internal/lsp/testdata/variadic/variadic.go.in
+++ b/internal/lsp/testdata/variadic/variadic.go.in
@@ -13,10 +13,10 @@ func _() {
 		ss []string //@item(vStrSlice, "ss", "[]string", "var")
 	)
 
-	foo()          //@rank(")", vInt, vStr),rank(")", vInt, vStrSlice)
-	foo(123, )     //@rank(")", vStr, vInt),rank(")", vStrSlice, vInt)
-	foo(123, "", ) //@rank(")", vStr, vInt),rank(")", vStr, vStrSlice)
-	foo(123, , "") //@rank(" ,", vStr, vInt),rank(")", vStr, vStrSlice)
+	foo()           //@rank(")", vInt, vStr),rank(")", vInt, vStrSlice)
+	foo(123, )      //@rank(")", vStr, vInt),rank(")", vStrSlice, vInt)
+	foo(123, "", )  //@rank(")", vStr, vInt),rank(")", vStr, vStrSlice)
+	foo(123, s, "") //@rank(", \"", vStr, vStrSlice)
 
   // snippet will add the "..." for you
 	foo(123, ) //@snippet(")", vStrSlice, "ss...", "ss..."),snippet(")", vFunc, "bar()...", "bar()..."),snippet(")", vStr, "s", "s")
diff --git a/internal/lsp/testdata/variadic/variadic_intf.go b/internal/lsp/testdata/variadic/variadic_intf.go
new file mode 100644
index 0000000000..6e23fc9960
--- /dev/null
+++ b/internal/lsp/testdata/variadic/variadic_intf.go
@@ -0,0 +1,21 @@
+package variadic
+
+type baz interface {
+	baz()
+}
+
+func wantsBaz(...baz) {}
+
+type bazImpl int
+
+func (bazImpl) baz() {}
+
+func _() {
+	var (
+		impls []bazImpl //@item(vImplSlice, "impls", "[]bazImpl", "var")
+		impl  bazImpl   //@item(vImpl, "impl", "bazImpl", "var")
+		bazes []baz     //@item(vIntfSlice, "bazes", "[]baz", "var")
+	)
+
+	wantsBaz() //@rank(")", vImpl, vImplSlice),rank(")", vIntfSlice, vImplSlice)
+}
diff --git a/internal/lsp/tests/completion.go b/internal/lsp/tests/completion.go
index 8936e506b0..ba5ec70f24 100644
--- a/internal/lsp/tests/completion.go
+++ b/internal/lsp/tests/completion.go
@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"fmt"
 	"sort"
+	"strconv"
 	"strings"
 
 	"golang.org/x/tools/internal/lsp/protocol"
@@ -28,6 +29,8 @@ func ToProtocolCompletionItem(item source.CompletionItem) protocol.CompletionIte
 		TextEdit: &protocol.TextEdit{
 			NewText: item.Snippet(),
 		},
+		// Negate score so best score has lowest sort text like real API.
+		SortText: fmt.Sprint(-item.Score),
 	}
 	if pItem.InsertText == "" {
 		pItem.InsertText = pItem.Label
@@ -64,11 +67,13 @@ func isBuiltin(label, detail string, kind protocol.CompletionItemKind) bool {
 	return false
 }
 
-func CheckCompletionOrder(want, got []protocol.CompletionItem) string {
+func CheckCompletionOrder(want, got []protocol.CompletionItem, strictScores bool) string {
 	var (
 		matchedIdxs []int
 		lastGotIdx  int
+		lastGotSort float64
 		inOrder     = true
+		errorMsg    = "completions out of order"
 	)
 	for _, w := range want {
 		var found bool
@@ -76,10 +81,19 @@ func CheckCompletionOrder(want, got []protocol.CompletionItem) string {
 			if w.Label == g.Label && w.Detail == g.Detail && w.Kind == g.Kind {
 				matchedIdxs = append(matchedIdxs, i)
 				found = true
+
 				if i < lastGotIdx {
 					inOrder = false
 				}
 				lastGotIdx = i
+
+				sort, _ := strconv.ParseFloat(g.SortText, 64)
+				if strictScores && len(matchedIdxs) > 1 && sort <= lastGotSort {
+					inOrder = false
+					errorMsg = "candidate scores not strictly decreasing"
+				}
+				lastGotSort = sort
+
 				break
 			}
 		}
@@ -95,7 +109,7 @@ func CheckCompletionOrder(want, got []protocol.CompletionItem) string {
 	}
 
 	if !inOrder {
-		return summarizeCompletionItems(-1, want, matched, "completions out of order")
+		return summarizeCompletionItems(-1, want, matched, errorMsg)
 	}
 
 	return ""