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

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

5 files changed, 32 insertions, 2 deletions

diff --git a/source/slang/slang-check-stmt.cpp b/source/slang/slang-check-stmt.cpp
index bc89dc94e..a61f48af6 100644
--- a/source/slang/slang-check-stmt.cpp
+++ b/source/slang/slang-check-stmt.cpp
@@ -151,6 +151,10 @@ namespace Slang
 
     Expr* SemanticsVisitor::checkPredicateExpr(Expr* expr)
     {
+        if (as<AssignExpr>(expr))
+        {
+            getSink()->diagnose(expr, Diagnostics::assignmentInPredicateExpr);
+        }
         Expr* e = expr;
         e = CheckTerm(e);
         e = coerce(m_astBuilder->getBoolType(), e);
diff --git a/source/slang/slang-diagnostic-defs.h b/source/slang/slang-diagnostic-defs.h
index 39ceb6678..fed4944d3 100644
--- a/source/slang/slang-diagnostic-defs.h
+++ b/source/slang/slang-diagnostic-defs.h
@@ -277,6 +277,7 @@ DIAGNOSTIC(30053, Error, breakLabelNotFound, "label '$0' used as break target is
 DIAGNOSTIC(30054, Error, targetLabelDoesNotMarkBreakableStmt, "invalid break target: statement labeled '$0' is not breakable.")
 DIAGNOSTIC(30055, Error, useOfNonShortCircuitingOperatorInDiffFunc, "non-short-circuiting `?:` operator is not allowed in a differentiable function, use `select` instead.")
 DIAGNOSTIC(30056, Warning, useOfNonShortCircuitingOperator, "non-short-circuiting `?:` operator is deprecated, use 'select' instead.")
+DIAGNOSTIC(30057, Error, assignmentInPredicateExpr, "use an assignment operation as predicate expression is not allowed, wrap the assignment with '()' to clarify the intent.")
 
 DIAGNOSTIC(30043, Error, getStringHashRequiresStringLiteral, "getStringHash parameter can only accept a string literal")
 
diff --git a/tests/compute/loop-unroll.slang b/tests/compute/loop-unroll.slang
index 9a3fa3ba4..c0ea7686c 100644
--- a/tests/compute/loop-unroll.slang
+++ b/tests/compute/loop-unroll.slang
@@ -1,7 +1,6 @@
 //TEST(compute):COMPARE_COMPUTE: -shaderobj
 //TEST(compute):COMPARE_COMPUTE:-dx12  -shaderobj
-//TODO(JS): This test fails with a crash in CreateComputePipelineState, so disabled for now
-//DISABLE_TEST(compute):COMPARE_COMPUTE:-dx12 -use-dxil -shaderobj
+//TEST(compute):COMPARE_COMPUTE:-dx12 -use-dxil -shaderobj
 //TEST(compute):COMPARE_COMPUTE:-cpu -shaderobj
 //TEST(compute):COMPARE_COMPUTE:-cuda -shaderobj
 // Note VK output is not loop unrolled
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 = {
+}