diff --git a/internal/lsp/source/completion/completion.go b/internal/lsp/source/completion/completion.go
index 0c1ff3f21b..a2dfae6984 100644
--- a/internal/lsp/source/completion/completion.go
+++ b/internal/lsp/source/completion/completion.go
@@ -2314,7 +2314,7 @@ func (ci candidateInference) applyTypeNameModifiers(typ types.Type) types.Type {
 // matchesVariadic returns true if we are completing a variadic
 // parameter and candType is a compatible slice type.
 func (ci candidateInference) matchesVariadic(candType types.Type) bool {
-	return ci.variadic && ci.objType != nil && types.AssignableTo(candType, types.NewSlice(ci.objType))
+	return ci.variadic && ci.objType != nil && assignableTo(candType, types.NewSlice(ci.objType))
 }
 
 // findSwitchStmt returns an *ast.CaseClause's corresponding *ast.SwitchStmt or
@@ -2640,7 +2640,7 @@ func (ci *candidateInference) candTypeMatches(cand *candidate) bool {
 			return false
 		}
 
-		if ci.convertibleTo != nil && types.ConvertibleTo(candType, ci.convertibleTo) {
+		if ci.convertibleTo != nil && convertibleTo(candType, ci.convertibleTo) {
 			return true
 		}
 
@@ -2728,7 +2728,7 @@ func considerTypeConversion(from, to types.Type, path []types.Object) bool {
 		return false
 	}
 
-	if !types.ConvertibleTo(from, to) {
+	if !convertibleTo(from, to) {
 		return false
 	}
 
@@ -2777,7 +2777,7 @@ func (ci *candidateInference) typeMatches(expType, candType types.Type) bool {
 
 	// 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)
+	return assignableTo(candType, expType)
 }
 
 // kindMatches reports whether candType's kind matches our expected
@@ -2840,7 +2840,7 @@ func (ci *candidateInference) assigneesMatch(cand *candidate, sig *types.Signatu
 			assignee = ci.assignees[i]
 		}
 
-		if assignee == nil {
+		if assignee == nil || assignee == types.Typ[types.Invalid] {
 			continue
 		}
 
@@ -2894,7 +2894,7 @@ func (c *completer) matchingTypeName(cand *candidate) bool {
 		//
 		// Where our expected type is "[]int", and we expect a type name.
 		if c.inference.objType != nil {
-			return types.AssignableTo(candType, c.inference.objType)
+			return assignableTo(candType, c.inference.objType)
 		}
 
 		// Default to saying any type name is a match.
diff --git a/internal/lsp/source/completion/util.go b/internal/lsp/source/completion/util.go
index cd7849af26..e6d3bfd745 100644
--- a/internal/lsp/source/completion/util.go
+++ b/internal/lsp/source/completion/util.go
@@ -321,3 +321,23 @@ func (c *completer) editText(from, to token.Pos, newText string) ([]protocol.Tex
 		NewText: newText,
 	}})
 }
+
+// assignableTo is like types.AssignableTo, but returns false if
+// either type is invalid.
+func assignableTo(x, to types.Type) bool {
+	if x == types.Typ[types.Invalid] || to == types.Typ[types.Invalid] {
+		return false
+	}
+
+	return types.AssignableTo(x, to)
+}
+
+// convertibleTo is like types.ConvertibleTo, but returns false if
+// either type is invalid.
+func convertibleTo(x, to types.Type) bool {
+	if x == types.Typ[types.Invalid] || to == types.Typ[types.Invalid] {
+		return false
+	}
+
+	return types.ConvertibleTo(x, to)
+}
diff --git a/internal/lsp/testdata/deep/deep.go b/internal/lsp/testdata/deep/deep.go
index 6ed5ff8399..6908824f82 100644
--- a/internal/lsp/testdata/deep/deep.go
+++ b/internal/lsp/testdata/deep/deep.go
@@ -28,6 +28,13 @@ func _() {
 	wantsContext(c) //@rank(")", ctxBackground),rank(")", ctxTODO)
 }
 
+func _() {
+	var cork struct{ err error }
+	cork.err         //@item(deepCorkErr, "cork.err", "error", "field")
+	context          //@item(deepContextPkg, "context", "\"context\"", "package")
+	var _ error = co //@rank(" //", deepCorkErr, deepContextPkg)
+}
+
 func _() {
 	// deepCircle is circular.
 	type deepCircle struct {
diff --git a/internal/lsp/testdata/summary.txt.golden b/internal/lsp/testdata/summary.txt.golden
index 0247551f8b..b6c6c07b15 100644
--- a/internal/lsp/testdata/summary.txt.golden
+++ b/internal/lsp/testdata/summary.txt.golden
@@ -6,7 +6,7 @@ CompletionSnippetCount = 106
 UnimportedCompletionsCount = 5
 DeepCompletionsCount = 5
 FuzzyCompletionsCount = 8
-RankedCompletionsCount = 163
+RankedCompletionsCount = 164
 CaseSensitiveCompletionsCount = 4
 DiagnosticsCount = 37
 FoldingRangesCount = 2
diff --git a/internal/lsp/testdata/summary_go1.18.txt.golden b/internal/lsp/testdata/summary_go1.18.txt.golden
index 7e8da12d76..9fadf63409 100644
--- a/internal/lsp/testdata/summary_go1.18.txt.golden
+++ b/internal/lsp/testdata/summary_go1.18.txt.golden
@@ -6,7 +6,7 @@ CompletionSnippetCount = 116
 UnimportedCompletionsCount = 5
 DeepCompletionsCount = 5
 FuzzyCompletionsCount = 8
-RankedCompletionsCount = 173
+RankedCompletionsCount = 174
 CaseSensitiveCompletionsCount = 4
 DiagnosticsCount = 37
 FoldingRangesCount = 2