Fix @import of empty file

src/stage1/analyze.cpp

@@ -1988,7 +1988,7 @@ static ZigType *analyze_fn_type(CodeGen *g, AstNode *proto_node, Scope *child_sc
             // behaviour when checking expected alignment with `@ptrToInt(fn_ptr)`
             // or similar. This commit proposes to make `align` expressions a
             // compile error when compiled to Wasm architecture.
-            // 
+            //
             // Some references:
             // [1] [Mozilla: WebAssembly Tables](https://developer.mozilla.org/en-US/docs/WebAssembly/Understanding_the_text_format#WebAssembly_tables)
             // [2] [Sunfishcode's Wasm Ref Manual](https://github.com/sunfishcode/wasm-reference-manual/blob/master/WebAssembly.md#indirect-call)
@@ -8052,10 +8052,13 @@ not_integer:
 }
 
 Error file_fetch(CodeGen *g, Buf *resolved_path, Buf *contents_buf) {
-    size_t len;
+    size_t len = 0xAA;
     const char *contents = stage2_fetch_file(&g->stage1, buf_ptr(resolved_path), buf_len(resolved_path), &len);
-    if (contents == nullptr)
+    if (len == 0) {
+        // File exists but is empty (otherwise it would be 0xAA)
+    } else if (contents == nullptr) {
         return ErrorFileNotFound;
+    }
     buf_init_from_mem(contents_buf, contents, len);
     return ErrorNone;
 }
@@ -9044,7 +9047,7 @@ static void resolve_llvm_types_optional(CodeGen *g, ZigType *type, ResolveStatus
                 8 * child_type->abi_align,
                 val_offset_in_bits,
                 ZigLLVM_DIFlags_Zero, child_llvm_di_type);
-    di_element_types[maybe_null_index] = 
+    di_element_types[maybe_null_index] =
         ZigLLVMCreateDebugMemberType(g->dbuilder, ZigLLVMTypeToScope(type->llvm_di_type),
                 "maybe", di_file, line,
                 8*g->builtin_types.entry_bool->abi_size,

test/stage1/behavior/import.zig

@@ -16,3 +16,7 @@ test "import in non-toplevel scope" {
     };
     expectEqual(@as(i32, 1234), S.foo());
 }
+
+test "import empty file" {
+    const empty = @import("import/empty.zig");
+}