Code quality improvements + add dedicated DeadRefTypes test

tamasvajk · igfoo · commit 47799ae04021 · 2022-05-10T19:51:28.000+01:00
diff --git a/java/ql/lib/config/semmlecode.dbscheme b/java/ql/lib/config/semmlecode.dbscheme
@@ -1224,7 +1224,7 @@ ktPropertyDelegates(
 )
 
 compiler_generated(
-  unique int id: @top ref,
+  unique int id: @element ref,
   int kind: int ref
-  // 1: Kotlin declaring classes of adapter functions
-);
+  // 1: Declaring classes of adapter functions in Kotlin
+)
diff --git a/java/ql/lib/semmle/code/java/Element.qll b/java/ql/lib/semmle/code/java/Element.qll
@@ -41,6 +41,9 @@ class Element extends @element, Top {
 
   /** Cast this element to a `Documentable`. */
   Documentable getDoc() { result = this }
+
+  /** Holds if this is an auxiliary program element generated by the compiler. */
+  predicate isCompilerGenerated() { compiler_generated(this, _) }
 }
 
 /**
diff --git a/java/ql/src/Violations of Best Practice/Dead Code/DeadRefTypes.ql b/java/ql/src/Violations of Best Practice/Dead Code/DeadRefTypes.ql
@@ -52,7 +52,7 @@ predicate dead(RefType dead) {
   // Insist all source ancestors are dead as well.
   forall(RefType t | t.fromSource() and t = getASuperTypePlus(dead) | dead(t)) and
   // Exclude compiler generated classes (e.g. declaring type of adapter functions in Kotlin)
-  not compiler_generated(dead, _)
+  not dead.isCompilerGenerated()
 }
 
 from RefType t, string kind
diff --git a/java/ql/test/kotlin/library-tests/reflection/reflection.ql b/java/ql/test/kotlin/library-tests/reflection/reflection.ql
@@ -87,4 +87,4 @@ query predicate modifiers(ClassInstanceExpr e, Method m, string modifier) {
   m.hasModifier(modifier)
 }
 
-query predicate compGenerated(Top t, int i) { compiler_generated(t, i) }
+query predicate compGenerated(Element e, int i) { compiler_generated(e, i) }
diff --git a/java/ql/test/kotlin/query-tests/DeadRefTypes/DeadRefTypes.expected b/java/ql/test/kotlin/query-tests/DeadRefTypes/DeadRefTypes.expected
@@ -0,0 +1 @@
+| test.kt:1:1:1:20 | C1 | Unused class: C1 is not referenced within this codebase. If not used as an external API it should be removed. |
diff --git a/java/ql/test/kotlin/query-tests/DeadRefTypes/DeadRefTypes.qlref b/java/ql/test/kotlin/query-tests/DeadRefTypes/DeadRefTypes.qlref
@@ -0,0 +1 @@
+Violations of Best Practice/Dead Code/DeadRefTypes.ql
diff --git a/java/ql/test/kotlin/query-tests/DeadRefTypes/test.kt b/java/ql/test/kotlin/query-tests/DeadRefTypes/test.kt
@@ -0,0 +1,15 @@
+private class C1 { }
+
+private class C2 { }
+
+fun fn() {
+    val c = C2()
+}
+
+fun fn1() = 5
+
+fun fn2(f: () -> Unit) = f()
+
+fun adapted() {
+    fn2(::fn1)
+}

Original file line number	Diff line number	Diff line change
`@@ -41,6 +41,9 @@ class Element extends @element, Top {`
`41`	`41`
`42`	`42`	/** Cast this element to a `Documentable`. */
`43`	`43`	`Documentable getDoc() { result = this }`
	`44`	`+`
	`45`	`+ /** Holds if this is an auxiliary program element generated by the compiler. */`
	`46`	`+ predicate isCompilerGenerated() { compiler_generated(this, _) }`
`44`	`47`	`}`
`45`	`48`
`46`	`49`	`/**`
Original file line number	Diff line number	Diff line change
`@@ -52,7 +52,7 @@ predicate dead(RefType dead) {`
`52`	`52`	`// Insist all source ancestors are dead as well.`
`53`	`53`	`forall(RefType t \| t.fromSource() and t = getASuperTypePlus(dead) \| dead(t)) and`
`54`	`54`	`// Exclude compiler generated classes (e.g. declaring type of adapter functions in Kotlin)`
`55`		`- not compiler_generated(dead, _)`
	`55`	`+ not dead.isCompilerGenerated()`
`56`	`56`	`}`
`57`	`57`
`58`	`58`	`from RefType t, string kind`
Original file line number	Diff line number	Diff line change
`@@ -87,4 +87,4 @@ query predicate modifiers(ClassInstanceExpr e, Method m, string modifier) {`
`87`	`87`	`m.hasModifier(modifier)`
`88`	`88`	`}`
`89`	`89`
`90`		`-query predicate compGenerated(Top t, int i) { compiler_generated(t, i) }`
	`90`	`+query predicate compGenerated(Element e, int i) { compiler_generated(e, i) }`
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	`+\| test.kt:1:1:1:20 \| C1 \| Unused class: C1 is not referenced within this codebase. If not used as an external API it should be removed. \|`
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	`+Violations of Best Practice/Dead Code/DeadRefTypes.ql`