style: include explicit this decorators in function types

Account for explicit-this parameter decorators in the same way as parameter decorators: wire explicitThisDecorators through FunctionTypeNode and Node.createFunctionType, keep it adjacent to explicitThisType, and leave range as the last constructor/helper parameter. Update all call sites accordingly.

Author: jtenner

src/ast.ts

@@ -155,10 +155,11 @@ export abstract class Node {
     parameters: ParameterNode[],
     returnType: TypeNode,
     explicitThisType: NamedTypeNode | null,
+    explicitThisDecorators: DecoratorNode[] | null,
     isNullable: bool,
     range: Range
   ): FunctionTypeNode {
-    return new FunctionTypeNode(parameters, returnType, explicitThisType, isNullable, range);
+    return new FunctionTypeNode(parameters, returnType, explicitThisType, explicitThisDecorators, isNullable, range);
   }
 
   static createOmittedType(
@@ -920,16 +921,15 @@ export class FunctionTypeNode extends TypeNode {
     public returnType: TypeNode,
     /** Explicitly provided this type, if any. */
     public explicitThisType: NamedTypeNode | null, // can't be a function
+    /** Decorators on an explicit `this` parameter, if any, preserved for transforms. */
+    public explicitThisDecorators: DecoratorNode[] | null,
     /** Whether nullable or not. */
     isNullable: bool,
     /** Source range. */
     range: Range
   ) {
     super(NodeKind.FunctionType, isNullable, range);
   }
-
-  /** Decorators on an explicit `this` parameter, if any, preserved for transforms. */
-  explicitThisDecorators: DecoratorNode[] | null = null;
 }
 
 /** Represents a type parameter. */

src/parser.ts

@@ -905,10 +905,10 @@ export class Parser extends DiagnosticEmitter {
       parameters,
       returnType,
       thisType,
+      thisDecorators,
       false,
       tn.range(startPos, tn.pos)
     );
-    functionType.explicitThisDecorators = thisDecorators;
     this.noteFunctionTypeParameterDecorators(functionType);
     return functionType;
   }
@@ -1617,10 +1617,10 @@ export class Parser extends DiagnosticEmitter {
       parameters,
       returnType,
       thisType,
+      this.parseParametersThisDecorators,
       false,
       tn.range(signatureStart, tn.pos)
     );
-    signature.explicitThisDecorators = this.parseParametersThisDecorators;
     this.noteFunctionTypeParameterDecorators(signature);
 
     let body: Statement | null = null;
@@ -1743,10 +1743,10 @@ export class Parser extends DiagnosticEmitter {
       parameters,
       returnType,
       explicitThis,
+      explicitThisDecorators,
       false,
       tn.range(signatureStart, tn.pos)
     );
-    signature.explicitThisDecorators = explicitThisDecorators;
     this.noteFunctionTypeParameterDecorators(signature);
 
     let body: Statement | null = null;
@@ -2390,10 +2390,10 @@ export class Parser extends DiagnosticEmitter {
         parameters,
         returnType,
         thisType,
+        this.parseParametersThisDecorators,
         false,
         tn.range(signatureStart, tn.pos)
       );
-      signature.explicitThisDecorators = this.parseParametersThisDecorators;
       this.noteFunctionTypeParameterDecorators(signature);
 
       let body: Statement | null = null;

src/program.ts

@@ -933,7 +933,10 @@ export class Program extends DiagnosticEmitter {
           Node.createSimpleTypeName(CommonNames.void_, range),
           null, false, range
         ),
-        null, false, range
+        null,
+        null,
+        false,
+        range
       );
     }
     return Node.createFunctionDeclaration(
@@ -2758,6 +2761,7 @@ export class Program extends DiagnosticEmitter {
           [],
           typeNode,
           null,
+          null,
           false,
           declaration.range
         ),
@@ -2786,6 +2790,7 @@ export class Program extends DiagnosticEmitter {
             ],
             Node.createOmittedType(declaration.name.range.atEnd),
             null,
+            null,
             false,
             declaration.range
           ),
@@ -4083,7 +4088,7 @@ export class PropertyPrototype extends DeclaredElement {
       fieldDeclaration.decorators,
       fieldDeclaration.flags | CommonFlags.Instance | CommonFlags.Get,
       null,
-      new FunctionTypeNode([], typeNode, null, false, nativeRange),
+      new FunctionTypeNode([], typeNode, null, null, false, nativeRange),
       null,
       nativeRange
     );
@@ -4110,7 +4115,10 @@ export class PropertyPrototype extends DeclaredElement {
           ),
           null, false, nativeRange
         ),
-        null, false, nativeRange
+        null,
+        null,
+        false,
+        nativeRange
       ),
       null, nativeRange
     );