cast std::count_if to size_t since it returns a signed value

Author: sbaluja

tools/code-generation/smithy/cpp-codegen/smithy-cpp-codegen/src/main/java/com/amazonaws/util/awsclientsmithygenerator/generators/waiters/jmespath/FilterOperandEmitter.java

@@ -98,8 +98,8 @@ private String emitItemCountIf(FilterProjectionExpression filterExpr) {
 
         String predicate = filterExpr.getComparison().accept(
             new FilterPredicateEmitter("inner", model, innerElementShape, smithyServiceName));
-        return "std::count_if(" + collection + ".begin(), " + collection + ".end(), "
-                + "[](const " + innerElementType + "& inner) { return " + predicate + "; })";
+        return "static_cast<std::size_t>(std::count_if(" + collection + ".begin(), " + collection + ".end(), "
+                + "[](const " + innerElementType + "& inner) { return " + predicate + "; }))";
     }
 
     private String resolveInnerElementType(JmespathExpression collectionExpr) {

tools/code-generation/smithy/cpp-codegen/smithy-cpp-codegen/src/main/java/com/amazonaws/util/awsclientsmithygenerator/generators/waiters/jmespath/ScalarEmitter.java

@@ -65,8 +65,8 @@ private String emitCountIf(FilterProjectionExpression filterExpr) {
 
         String predicate = filterExpr.getComparison().accept(
             new FilterPredicateEmitter("item", model, elementShape, smithyServiceName));
-        return "std::count_if(" + collection + ".begin(), " + collection + ".end(), "
-                + "[](const " + elementType + "& item) { return " + predicate + "; })";
+        return "static_cast<std::size_t>(std::count_if(" + collection + ".begin(), " + collection + ".end(), "
+                + "[](const " + elementType + "& item) { return " + predicate + "; }))";
     }
 
     private String resolveFilterElementType(FilterProjectionExpression filterExpr) {

tools/code-generation/smithy/cpp-codegen/smithy-cpp-codegen/src/test/java/com/amazonaws/util/awsclientsmithygenerator/generators/waiters/WaiterJmesPathCppCodeGeneratorTest.java

@@ -543,7 +543,7 @@ void andExpression_bracesBalanced() {
         void filterProjectionComparison_withoutAnd() {
             String expr = "length(Items[?Status == 'DISABLED' || Status == 'FAILED']) == length(Items)";
             String code = gen(expr, PathComparator.BOOLEAN_EQUALS);
-            assertContains(code, "std::count_if");
+            assertContains(code, "static_cast<std::size_t>(std::count_if");
             assertContains(code, "item.GetStatus() == \"DISABLED\"");
             assertContains(code, "item.GetStatus() == \"FAILED\"");
             assertContains(code, "result.GetItems().size()");