Specify lambda method for big arity lambdas

tamasvajk · igfoo · commit 7b58d01eff79 · 2022-05-10T19:51:10.000+01:00
diff --git a/java/kotlin-extractor/src/main/kotlin/KotlinFileExtractor.kt b/java/kotlin-extractor/src/main/kotlin/KotlinFileExtractor.kt
@@ -1677,8 +1677,6 @@ open class KotlinFileExtractor(
 
                 if (types.size > BuiltInFunctionArity.BIG_ARITY) {
                     implementFunctionNInvoke(e.function, ids, locId, parameters)
-
-                    // todo: which method should be returned in `LambdaExpr.asMethod()`?
                 }
 
                 val exprParent = parent.expr(e, callable)
diff --git a/java/ql/lib/semmle/code/java/Expr.qll b/java/ql/lib/semmle/code/java/Expr.qll
@@ -1256,7 +1256,21 @@ class LambdaExpr extends FunctionalExpr, @lambdaexpr {
    * Gets the implicit method corresponding to this lambda expression.
    * The parameters of the lambda expression are the parameters of this method.
    */
-  override Method asMethod() { result = this.getAnonymousClass().getAMethod() }
+  override Method asMethod() {
+    not isKotlinFunctionN() and
+    result = this.getAnonymousClass().getAMethod()
+    or
+    isKotlinFunctionN() and
+    result = this.getAnonymousClass().getAMethod() and
+    result.getNumberOfParameters() = 1
+  }
+
+  predicate isKotlinFunctionN() {
+    exists(RefType r |
+      this.getAnonymousClass().extendsOrImplements(r) and
+      r.getSourceDeclaration().hasQualifiedName("kotlin.jvm.functions", "FunctionN")
+    )
+  }
 
   /** Holds if the body of this lambda is an expression. */
   predicate hasExprBody() { lambdaKind(this, 0) }
@@ -2202,9 +2216,7 @@ class WhenBranch extends Top, @whenbranch {
   predicate isElseBranch() { when_branch_else(this) }
 
   /** Gets the `when` expression this is a branch of. */
-  WhenExpr getWhenExpr() {
-    this = result.getBranch(_)
-  }
+  WhenExpr getWhenExpr() { this = result.getBranch(_) }
 
   override string toString() { result = "... -> ..." }
 
diff --git a/java/ql/test/kotlin/library-tests/exprs/funcExprs.expected b/java/ql/test/kotlin/library-tests/exprs/funcExprs.expected
@@ -11,5 +11,4 @@
 | funcExprs.kt:25:28:25:51 | ...->... | stmt body | funcExprs.kt:25:28:25:51 | invoke | invoke(int) | funcExprs.kt:25:28:25:51 | new Function1<Integer,Function1<Integer,Double>>(...) { ... } |
 | funcExprs.kt:25:37:25:47 | ...->... | stmt body | funcExprs.kt:25:37:25:47 | invoke | invoke(int) | funcExprs.kt:25:37:25:47 | new Function1<Integer,Double>(...) { ... } |
 | funcExprs.kt:27:29:27:112 | ...->... | stmt body | funcExprs.kt:27:29:27:112 | invoke | invoke(int,int,int,int,int,int,int,int,int,int,int,int,int,int,int,int,int,int,int,int,int,int) | funcExprs.kt:27:29:27:112 | new Function22<Integer,Integer,Integer,Integer,Integer,Integer,Integer,Integer,Integer,Integer,Integer,Integer,Integer,Integer,Integer,Integer,Integer,Integer,Integer,Integer,Integer,Integer,Unit>(...) { ... } |
-| funcExprs.kt:28:29:28:117 | ...->... | stmt body | funcExprs.kt:28:29:28:117 | invoke | invoke(int,int,int,int,int,int,int,int,int,int,int,int,int,int,int,int,int,int,int,int,int,int,int) | funcExprs.kt:28:29:28:117 | new FunctionN<String>(...) { ... } |
 | funcExprs.kt:28:29:28:117 | ...->... | stmt body | funcExprs.kt:28:29:28:117 | invoke | invoke(java.lang.Object[]) | funcExprs.kt:28:29:28:117 | new FunctionN<String>(...) { ... } |

Original file line number	Diff line number	Diff line change
`@@ -1677,8 +1677,6 @@ open class KotlinFileExtractor(`
`1677`	`1677`
`1678`	`1678`	`if (types.size > BuiltInFunctionArity.BIG_ARITY) {`
`1679`	`1679`	`implementFunctionNInvoke(e.function, ids, locId, parameters)`
`1680`		`-`
`1681`		- // todo: which method should be returned in `LambdaExpr.asMethod()`?
`1682`	`1680`	`}`
`1683`	`1681`
`1684`	`1682`	`val exprParent = parent.expr(e, callable)`