Make a warning if a [mutating] method is called on an in param. (#3184)

* Make a warning if a [mutating] method is passed as an in param.

* Kick CI.

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Co-authored-by: Yong He <yonghe@outlook.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/tests/diagnostics/param-mutation.slang.expected b/tests/diagnostics/param-mutation.slang.expected
new file mode 100644
index 000000000..a1fb34fb7
--- /dev/null
+++ b/tests/diagnostics/param-mutation.slang.expected
@@ -0,0 +1,8 @@
+result code = 0
+standard error = {
+tests/diagnostics/param-mutation.slang(17): warning 30068: mutating method 'setValue' called on `in` parameter 's'; changes will not be visible to caller. copy the parameter into a local variable if this behavior is intended
+    s.setValue(v + 1);
+              ^
+}
+standard output = {
+}