diff --git a/src/analyze.cpp b/src/analyze.cpp
index 699b121276..afe0fe6849 100644
--- a/src/analyze.cpp
+++ b/src/analyze.cpp
@@ -4012,6 +4012,10 @@ static void resolve_decl_var(CodeGen *g, TldVar *tld_var, bool allow_lazy) {
     } else if (!is_extern) {
         add_node_error(g, source_node, buf_sprintf("variables must be initialized"));
         implicit_type = g->builtin_types.entry_invalid;
+    } else if (explicit_type == nullptr) {
+        // extern variable without explicit type
+        add_node_error(g, source_node, buf_sprintf("unable to infer variable type"));
+        implicit_type = g->builtin_types.entry_invalid;
     }
 
     ZigType *type = explicit_type ? explicit_type : implicit_type;
diff --git a/test/compile_errors.zig b/test/compile_errors.zig
index adf92800fe..611094c050 100644
--- a/test/compile_errors.zig
+++ b/test/compile_errors.zig
@@ -2,6 +2,15 @@ const tests = @import("tests.zig");
 const std = @import("std");
 
 pub fn addCases(cases: *tests.CompileErrorContext) void {
+    cases.add("extern variable has no type",
+        \\extern var foo;
+        \\pub export fn entry() void {
+        \\    foo;
+        \\}
+    , &[_][]const u8{
+        "tmp.zig:1:1: error: unable to infer variable type",
+    });
+
     cases.add("@src outside function",
         \\comptime {
         \\    @src();