Kotlin: Add support for string templates

java/kotlin-extractor/src/main/kotlin/KotlinExtractorExtension.kt

@@ -1419,6 +1419,17 @@ class X {
                 val exprParent = parent.expr(e, callable)
                 extractCall(e, callable, exprParent.parent, exprParent.idx)
             }
+            is IrStringConcatenation -> {
+                val exprParent = parent.expr(e, callable)
+                val id = tw.getFreshIdLabel<DbStringtemplateexpr>()
+                val type = useType(e.type)
+                val locId = tw.getLocation(e)
+                tw.writeExprs_stringtemplateexpr(id, type.javaResult.id, type.kotlinResult.id, exprParent.parent, exprParent.idx)
+                tw.writeHasLocation(id, locId)
+                e.arguments.forEachIndexed { i, a ->
+                    extractExpressionExpr(a, callable, id, i)
+                }
+            }
             is IrConst<*> -> {
                 val exprParent = parent.expr(e, callable)
                 val v = e.value

java/ql/lib/config/semmlecode.dbscheme

@@ -670,6 +670,7 @@ case @expr.kind of
 | 77  = @safecastexpr
 | 78  = @notinstanceofexpr
 | 79  = @stmtexpr
+| 80  = @stringtemplateexpr
 ;
 
 /** Holds if this `when` expression was written as an `if` expression. */

java/ql/lib/semmle/code/java/Expr.qll

@@ -2246,3 +2246,24 @@ class StmtExpr extends Expr, @stmtexpr {
 
   override string getAPrimaryQlClass() { result = "StmtExpr" }
 }
+
+/**
+ * A Kotlin string template expression. For example, `"foo${bar}baz"`.
+ */
+class StringTemplateExpr extends Expr, @stringtemplateexpr {
+  /**
+   * Gets the `i`th component of this string template.
+   *
+   * For example, in the string template `"foo${bar}baz"`, the 0th
+   * component is the string literal `"foo"`, the 1st component is
+   * the variable access `bar`, and the 2nd component is the string
+   * literal `"bar"`.
+   */
+  Expr getComponent(int i) { result.isNthChildOf(this, i) }
+
+  override string toString() { result = "\"...\"" }
+
+  override string getHalsteadID() { result = "StringTemplateExpr" }
+
+  override string getAPrimaryQlClass() { result = "StringTemplateExpr" }
+}