QL: add no-uppercase-variables query

ql/ql/src/codeql_ql/style/AcronymsShouldBeCamelCaseQuery.qll

@@ -29,6 +29,24 @@ string getName(AstNode node, string kind) {
   result = node.(Module).getName() and kind = "module"
 }
 
+string prettyPluralKind(string kind) {
+  kind = "class" and result = "classes"
+  or
+  kind = "classlessPredicate" and result = "predicates"
+  or
+  kind = "classPredicate" and result = "class predicates"
+  or
+  kind = "newtypeBranch" and result = "newtype branches"
+  or
+  kind = "newtype" and result = "newtypes"
+  or
+  kind = "variable" and result = "variables"
+  or
+  kind = "field" and result = "fields"
+  or
+  kind = "module" and result = "modules"
+}
+
 /**
  * Holds if `name` seems to contain an upper-cased acronym that could be pascal-cased.
  * `name` is the name of `node`, and `kind` describes what kind of definition `node` is.

ql/ql/src/queries/style/NoUppercaseVariables.ql

@@ -0,0 +1,42 @@
+/**
+ * @name No upper case variables
+ * @description Variables/fields/predicates should be lower-case, classes/modules should be upper-case
+ * @kind problem
+ * @problem.severity error
+ * @id ql/no-upper-case-variables
+ * @tags correctness
+ * @precision very-high
+ */
+
+import ql
+import codeql_ql.style.AcronymsShouldBeCamelCaseQuery as AcronymsQuery
+
+predicate shouldBeUpperCase(AstNode node, string name, string kind) {
+  name = AcronymsQuery::getName(node, kind) and
+  kind = ["class", "newtypeBranch", "newtype", "module"]
+}
+
+predicate shouldBeLowerCase(AstNode node, string name, string kind) {
+  name = AcronymsQuery::getName(node, kind) and
+  not shouldBeUpperCase(node, name, kind)
+}
+
+string prettyKind(string kind) {
+  exists(string prettyLower | prettyLower = AcronymsQuery::prettyPluralKind(kind) |
+    result = prettyLower.prefix(1).toUpperCase() + prettyLower.suffix(1)
+  )
+}
+
+from string name, AstNode node, string message, string kind
+where
+  (
+    shouldBeLowerCase(node, name, kind) and
+    name.regexpMatch("[A-Z].*") and
+    message = "lowercase"
+    or
+    shouldBeUpperCase(node, name, kind) and
+    name.regexpMatch("[a-z].*") and
+    message = "uppercase"
+  ) and
+  not node.hasAnnotation("deprecated")
+select node, prettyKind(kind) + " should start with an " + message + " letter."