Commit 4f594527c0

@@ -4398,6 +4398,7 @@ static Error analyze_callee_async(CodeGen *g, ZigFn *fn, ZigFn *callee, AstNode
         }
     }
     if (callee_is_async) {
+        bool bad_recursion = (fn->inferred_async_node == inferred_async_none);
         fn->inferred_async_node = call_node;
         fn->inferred_async_fn = callee;
         if (must_not_be_async) {
@@ -4407,6 +4408,12 @@ static Error analyze_callee_async(CodeGen *g, ZigFn *fn, ZigFn *callee, AstNode
             add_async_error_notes(g, msg, fn);
             return ErrorSemanticAnalyzeFail;
         }
+        if (bad_recursion) {
+            ErrorMsg *msg = add_node_error(g, fn->proto_node,
+                buf_sprintf("recursive function cannot be async"));
+            add_async_error_notes(g, msg, fn);
+            return ErrorSemanticAnalyzeFail;
+        }
         if (fn->assumed_non_async != nullptr) {
             ErrorMsg *msg = add_node_error(g, fn->proto_node,
                 buf_sprintf("unable to infer whether '%s' should be async",

@@ -3917,6 +3917,7 @@ static LLVMValueRef ir_render_call(CodeGen *g, IrExecutable *executable, IrInstr
             if (instruction->modifier == CallModifierAsync) {
                 frame_result_loc = result_loc;
             } else {
+                src_assert(instruction->frame_result_loc != nullptr, instruction->base.source_node);
                 frame_result_loc_uncasted = ir_llvm_value(g, instruction->frame_result_loc);
                 src_assert(instruction->fn_entry != nullptr, instruction->base.source_node);
                 frame_result_loc = LLVMBuildBitCast(g->builder, frame_result_loc_uncasted,