Diagnose on using assignment as predicate expr. (#2774)

Co-authored-by: Yong He <yhe@nvidia.com>

2 files changed, 26 insertions, 0 deletions

diff --git a/tests/diagnostics/assign-in-if.slang b/tests/diagnostics/assign-in-if.slang
new file mode 100644
index 000000000..ef2222365
--- /dev/null
+++ b/tests/diagnostics/assign-in-if.slang
@@ -0,0 +1,12 @@
+//DIAGNOSTIC_TEST:REFLECTION:-stage compute -entry main -target hlsl
+
+[numthreads(1, 1, 1)]
+void main(
+    uint3 dispatchThreadID : SV_DispatchThreadID)
+{
+    int a = 1;
+    if (a = 0) // error
+    {}
+    if ((a = 0)) // ok.
+    {}
+}
\ No newline at end of file
diff --git a/tests/diagnostics/assign-in-if.slang.expected b/tests/diagnostics/assign-in-if.slang.expected
new file mode 100644
index 000000000..373072d66
--- /dev/null
+++ b/tests/diagnostics/assign-in-if.slang.expected
@@ -0,0 +1,14 @@
+result code = 1
+standard error = {
+tests/diagnostics/assign-in-if.slang(8): error 30057: use an assignment operation as predicate expression is not allowed, wrap the assignment with '()' to clarify the intent.
+    if (a = 0) // error
+          ^
+tests/diagnostics/assign-in-if.slang(8): warning 30081: implicit conversion from 'int' to 'bool' is not recommended
+    if (a = 0) // error
+          ^
+tests/diagnostics/assign-in-if.slang(10): warning 30081: implicit conversion from 'int' to 'bool' is not recommended
+    if ((a = 0)) // ok.
+        ^
+}
+standard output = {
+}