diff --git a/src/analyze.cpp b/src/analyze.cpp
index 49f8e093a0..a97ec513ad 100644
--- a/src/analyze.cpp
+++ b/src/analyze.cpp
@@ -1376,6 +1376,10 @@ static TypeTableEntry *analyze_fn_type(CodeGen *g, AstNode *proto_node, Scope *c
     fn_type_id.return_type = (fn_proto->return_type == nullptr) ?
         g->builtin_types.entry_void : analyze_type_expr(g, child_scope, fn_proto->return_type);
 
+    if (type_is_invalid(fn_type_id.return_type)) {
+        return g->builtin_types.entry_invalid;
+    }
+
     if (fn_type_id.cc != CallingConventionUnspecified && !type_allowed_in_extern(g, fn_type_id.return_type)) {
         add_node_error(g, fn_proto->return_type,
                 buf_sprintf("return type '%s' not allowed in function with calling convention '%s'",
@@ -1386,7 +1390,7 @@ static TypeTableEntry *analyze_fn_type(CodeGen *g, AstNode *proto_node, Scope *c
 
     switch (fn_type_id.return_type->id) {
         case TypeTableEntryIdInvalid:
-            return g->builtin_types.entry_invalid;
+            zig_unreachable();
 
         case TypeTableEntryIdUndefLit:
         case TypeTableEntryIdNullLit:
diff --git a/test/compile_errors.zig b/test/compile_errors.zig
index cc28f29f26..64ee69ba18 100644
--- a/test/compile_errors.zig
+++ b/test/compile_errors.zig
@@ -1,6 +1,10 @@
 const tests = @import("tests.zig");
 
 pub fn addCases(cases: &tests.CompileErrorContext) void {
+    cases.add("function with invalid return type",
+        \\export fn foo() boid {}
+    , ".tmp_source.zig:1:17: error: use of undeclared identifier 'boid'");
+
     cases.add("function with non-extern enum parameter",
         \\const Foo = enum { A, B, C };
         \\export fn entry(foo: Foo) void { }