Swift: add an internal query-suite for listing all the compiler errors

swift/ql/lib/codeql/swift/elements/Diagnostics.qll

@@ -1,5 +1,31 @@
 private import codeql.swift.generated.Diagnostics
 
 class Diagnostics extends Generated::Diagnostics {
-  override string toString() { result = getText() }
+  override string toString() { result = getSeverity() + ": " + getText() }
+
+  string getSeverity() {
+    getKind() = 1 and result = "error"
+    or
+    getKind() = 2 and result = "warning"
+    or
+    getKind() = 3 and result = "note"
+    or
+    getKind() = 4 and result = "remark"
+  }
+}
+
+class CompilerError extends Diagnostics {
+  CompilerError() { this.getSeverity() = "error" }
+}
+
+class CompilerWarning extends Diagnostics {
+  CompilerWarning() { this.getSeverity() = "warning" }
+}
+
+class CompilerNote extends Diagnostics {
+  CompilerNote() { this.getSeverity() = "note" }
+}
+
+class CompilerRemark extends Diagnostics {
+  CompilerRemark() { this.getSeverity() = "remark" }
 }

swift/ql/src/diagnostics/internal/CompilerErrors.ql

@@ -0,0 +1,11 @@
+/**
+ * @name Compiler errors
+ * @description List all compiler errors for files in the source code directory.
+ * @kind diagnostic
+ * @id swift/diagnostics/compiler-errors
+ */
+
+import swift
+
+from CompilerError error
+select error, "Compiler error in " + error.getFile() + " with error message " + error.getText()

swift/ql/test/extractor-tests/generated/Diagnostics/Diagnostics.expected

@@ -1,3 +1,3 @@
-| diags.swift:1:10:1:10 | Hello, warning | getText: | Hello, warning | getKind: | 2 |
-| error.swift:2:14:2:14 | cannot convert value of type 'String' to specified type 'Int' | getText: | cannot convert value of type 'String' to specified type 'Int' | getKind: | 1 |
-| import-error.swift:2:8:2:8 | no such module 'FooBar' | getText: | no such module 'FooBar' | getKind: | 1 |
+| diags.swift:1:10:1:10 | warning: Hello, warning | getText: | Hello, warning | getKind: | 2 |
+| error.swift:2:14:2:14 | error: cannot convert value of type 'String' to specified type 'Int' | getText: | cannot convert value of type 'String' to specified type 'Int' | getKind: | 1 |
+| import-error.swift:2:8:2:8 | error: no such module 'FooBar' | getText: | no such module 'FooBar' | getKind: | 1 |