[WGSL] Constant size for array types should be concretized

https://bugs.webkit.org/show_bug.cgi?id=274149
rdar://127986684

Reviewed by Mike Wyrzykowski.

The size of an array type has to be a concrete integer, but we were using the
constant value without concretizing, so 64-bit integers were allowed.

* Source/WebGPU/WGSL/TypeCheck.cpp:
(WGSL::TypeChecker::visit):
* Source/WebGPU/WGSL/tests/invalid/array.wgsl:

Canonical link: https://commits.webkit.org/278761@main

Source/WebGPU/WGSL/TypeCheck.cpp

@@ -1708,10 +1708,13 @@ void TypeChecker::visit(AST::ArrayTypeExpression& array)
 
         auto value = array.maybeElementCount()->constantValue();
         if (value.has_value()) {
-            auto elementCount = value->integerValue();
-            if (elementCount < 1) {
-                typeError(array.span(), "array count must be greater than 0"_s);
-                return;
+            int64_t elementCount = 0;
+            if (convertValue(array.maybeElementCount()->span(), concretize(elementCountType, m_types), value)) {
+                elementCount = value->integerValue();
+                if (elementCount < 1) {
+                    typeError(array.span(), "array count must be greater than 0"_s);
+                    return;
+                }
             }
             size = { static_cast<unsigned>(elementCount) };
         } else

Source/WebGPU/WGSL/tests/invalid/array.wgsl

@@ -3,6 +3,9 @@
 // CHECK-L: 'array' requires at least 1 template argument
 var<private> a:array;
 
+// CHECK-L: value 4294967296 cannot be represented as 'i32'
+@group(0) @binding(0) var<storage, read_write> b: array<u32, (1<<32)>;
+
 fn testArrayLengthMismatch() {
   // CHECK-L: array count must be greater than 0
   let x1 = array<i32, 0>();