JS: Fix extraction of non-substitution template literal types

javascript/extractor/src/com/semmle/ts/extractor/TypeScriptASTConverter.java

@@ -5,7 +5,6 @@ import java.util.Collections;
 import java.util.List;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
-import java.util.stream.Collectors;
 
 import com.google.gson.JsonArray;
 import com.google.gson.JsonElement;
@@ -1001,10 +1000,10 @@ public class TypeScriptASTConverter {
   private Node convertConditionalType(JsonObject node, SourceLocation loc) throws ParseError {
     return new ConditionalTypeExpr(
         loc,
-        convertChild(node, "checkType"),
-        convertChild(node, "extendsType"),
-        convertChild(node, "trueType"),
-        convertChild(node, "falseType"));
+        convertChildAsType(node, "checkType"),
+        convertChildAsType(node, "extendsType"),
+        convertChildAsType(node, "trueType"),
+        convertChildAsType(node, "falseType"));
   }
 
   private SourceLocation getSourceRange(Position from, Position to) {
@@ -1613,6 +1612,10 @@ public class TypeScriptASTConverter {
         literal = new Literal(loc, arg.getTokenType(), "-" + arg.getValue());
       }
     }
+    if (literal instanceof TemplateLiteral) {
+      // A LiteralType containing a NoSubstitutionTemplateLiteral must produce a TemplateLiteralTypeExpr
+      return new TemplateLiteralTypeExpr(literal.getLoc(), new ArrayList<>(), ((TemplateLiteral)literal).getQuasis());
+    }
     return literal;
   }
 
@@ -1842,7 +1845,7 @@ public class TypeScriptASTConverter {
   }
 
   private Node convertOptionalType(JsonObject node, SourceLocation loc) throws ParseError {
-    return new OptionalTypeExpr(loc, convertChild(node, "type"));
+    return new OptionalTypeExpr(loc, convertChildAsType(node, "type"));
   }
 
   private ITypeExpression asType(Node node) {

javascript/ql/test/library-tests/TypeScript/RegressionTests/TemplateTypes/TemplateTypes.expected

@@ -0,0 +1,6 @@
+| tst.ts:2:11:2:21 | `foo ${T1}` |
+| tst.ts:4:45:4:49 | `foo` |
+| tst.ts:4:53:4:57 | `bar` |
+| tst.ts:5:46:5:50 | `foo` |
+| tst.ts:5:54:5:63 | `bar ${K}` |
+| tst.ts:7:15:7:19 | `foo` |

javascript/ql/test/library-tests/TypeScript/RegressionTests/TemplateTypes/TemplateTypes.ql

@@ -0,0 +1,3 @@
+import javascript
+
+query TemplateLiteralTypeExpr literalType() { any() }

javascript/ql/test/library-tests/TypeScript/RegressionTests/TemplateTypes/tsconfig.json

@@ -0,0 +1,3 @@
+{
+    "include": ["."]
+}

javascript/ql/test/library-tests/TypeScript/RegressionTests/TemplateTypes/tst.ts

@@ -0,0 +1,7 @@
+type T1 = 'foo' | 'bar';
+type T2 = `foo ${T1}`;
+
+type FooToBar<K extends string> = K extends `foo` ? `bar` : K;
+type FooToBar2<K extends string> = K extends `foo` ? `bar ${K}` : K;
+
+type Tuple = [`foo`?];