Fix to allow defining variables of link-time size.

Author: csyonghe

source/slang/slang-ast-decl.h

@@ -137,7 +137,8 @@ enum class TypeTag
 {
     None = 0,
     Unsized = 1,
-    Incomplete = 2
+    Incomplete = 2,
+    LinkTimeSized = 4,
 };
 
 // Declaration of a type that represents some sort of aggregate

source/slang/slang-check-conformance.cpp

@@ -274,7 +274,8 @@ namespace Slang
             }
             else if (auto intVal = arrayType->getElementCount())
             {
-                sized = !intVal->isLinkTimeVal();
+                sized = true;
+                typeTag = (TypeTag)((int)typeTag | (int)TypeTag::LinkTimeSized);
             }
             if (!sized)
                 typeTag = (TypeTag)((int)typeTag | (int)TypeTag::Unsized);

source/slang/slang-check-decl.cpp

@@ -2053,8 +2053,9 @@ namespace Slang
         if (parentDecl)
         {
             parentDecl->addTag(getVarTypeTags());
-            bool isUnsized = (((int)getVarTypeTags() & (int)TypeTag::Unsized) != 0);
-            if (isUnsized)
+            auto unsizedMask = (int)TypeTag::Unsized | (int)TypeTag::LinkTimeSized;
+            bool isUnknownSize = (((int)getVarTypeTags() & unsizedMask) != 0);
+            if (isUnknownSize)
             {
                 // Unsized decl must appear as the last member of the struct.
                 for (auto memberIdx = parentDecl->members.getCount() - 1; memberIdx >= 0; memberIdx--)

tests/bugs/gh-4150.slang

@@ -1,5 +1,6 @@
 //TEST:SIMPLE(filecheck=CHECK1):-target spirv -DERROR1
 //TEST:SIMPLE(filecheck=CHECK2):-target spirv -DERROR2
+extern static const int constValue = 1;
 
 struct RWTex<T : __BuiltinRealType, let N : uint>
 {
@@ -42,4 +43,7 @@ void main(uint3 pixel_i : SV_DispatchThreadID)
 
     //CHECK1-NOT:([[# @LINE+1]]): error
     float sa4[] = { 1, 2, 3 }; // should be ok.
+
+    //CHECK1-NOT:([[# @LINE+1]]): error
+    float sa5[constValue]; // should be ok.
 }