1 files changed, 95 insertions, 0 deletions
diff --git a/tests/run-make/option-output-no-space/rmake.rs b/tests/run-make/option-output-no-space/rmake.rs
new file mode 100644
index 00000000000..2c42f15aa89
--- /dev/null
+++ b/tests/run-make/option-output-no-space/rmake.rs
@@ -0,0 +1,95 @@
+// This test is to check if the warning is emitted when no space
+// between `-o` and arg is applied, see issue #142812
+
+//@ ignore-cross-compile
+use run_make_support::rustc;
+
+fn main() {
+    // test fake args
+    rustc()
+        .input("main.rs")
+        .arg("-optimize")
+        .run()
+        .assert_stderr_contains(
+            "warning: option `-o` has no space between flag name and value, which can be confusing",
+        )
+        .assert_stderr_contains(
+            "note: output filename `-o ptimize` is applied instead of a flag named `optimize`",
+        );
+    rustc()
+        .input("main.rs")
+        .arg("-o0")
+        .run()
+        .assert_stderr_contains(
+            "warning: option `-o` has no space between flag name and value, which can be confusing",
+        )
+        .assert_stderr_contains(
+            "note: output filename `-o 0` is applied instead of a flag named `o0`",
+        );
+    rustc().input("main.rs").arg("-o1").run();
+    // test real args by iter optgroups
+    rustc()
+        .input("main.rs")
+        .arg("-out-dir")
+        .run()
+        .assert_stderr_contains(
+            "warning: option `-o` has no space between flag name and value, which can be confusing",
+        )
+        .assert_stderr_contains(
+            "note: output filename `-o ut-dir` is applied instead of a flag named `out-dir`",
+        )
+        .assert_stderr_contains(
+            "help: insert a space between `-o` and `ut-dir` if this is intentional: `-o ut-dir`",
+        );
+    // test real args by iter CG_OPTIONS
+    rustc()
+        .input("main.rs")
+        .arg("-opt_level")
+        .run()
+        .assert_stderr_contains(
+            "warning: option `-o` has no space between flag name and value, which can be confusing",
+        )
+        .assert_stderr_contains(
+            "note: output filename `-o pt_level` is applied instead of a flag named `opt_level`",
+        )
+        .assert_stderr_contains(
+            "help: insert a space between `-o` and `pt_level` if this is intentional: `-o pt_level`"
+        );
+    // separater in-sensitive
+    rustc()
+        .input("main.rs")
+        .arg("-opt-level")
+        .run()
+        .assert_stderr_contains(
+            "warning: option `-o` has no space between flag name and value, which can be confusing",
+        )
+        .assert_stderr_contains(
+            "note: output filename `-o pt-level` is applied instead of a flag named `opt-level`",
+        )
+        .assert_stderr_contains(
+            "help: insert a space between `-o` and `pt-level` if this is intentional: `-o pt-level`"
+        );
+    rustc()
+        .input("main.rs")
+        .arg("-overflow-checks")
+        .run()
+        .assert_stderr_contains(
+            "warning: option `-o` has no space between flag name and value, which can be confusing",
+        )
+        .assert_stderr_contains(
+            "note: output filename `-o verflow-checks` \
+            is applied instead of a flag named `overflow-checks`",
+        )
+        .assert_stderr_contains(
+            "help: insert a space between `-o` and `verflow-checks` \
+            if this is intentional: `-o verflow-checks`",
+        );
+
+    // No warning for Z_OPTIONS
+    rustc().input("main.rs").arg("-oom").run().assert_stderr_equals("");
+
+    // test no warning when there is space between `-o` and arg
+    rustc().input("main.rs").arg("-o").arg("ptimize").run().assert_stderr_equals("");
+    rustc().input("main.rs").arg("--out-dir").arg("xxx").run().assert_stderr_equals("");
+    rustc().input("main.rs").arg("-o").arg("out-dir").run().assert_stderr_equals("");
+}