Intersection Type #1603

markwpearce · 2025-12-15T20:42:14Z

Adds IntersectionType modelled after TypeScript's intersection types

Add IntersectionType
Add parsing for <type> and <type>
Allow "Grouped types" in parser (eg: (type1 or type2) and (type3 or type4))
Update type compatibility and other helpers to work with intersection types
Verify scope validation
Use order of operations on types, eg. type foo = myType1 or myType2 and myType3 or myType4 => myType1 or (myType2 and myType3) or myType4
Make sure type MyKlassAA = MyKlass and roAssociativeArray works properly
Test intersections with callfuncs
Add docs

…n and using union type in BRS mode

src/parser/Parser.ts

markwpearce · 2026-01-05T13:13:26Z

src/parser/Parser.ts

+            expressionsWithOperator.push({ expression: expr });
+
+            // handle expressions with order of operations - first "and", then "or"
+            const combineExpressions = (opToken: TokenKind) => {


Potentially there is a better way of doing this...

This algorithm just gets a list of <type> <operator?>, and then first loops through it to combine all ands into binary expressions, then again to combine all ors

I think in practice, this is fine, though

markwpearce · 2026-01-05T13:15:29Z

src/parser/Parser.ts

            if (this.match(TokenKind.LeftCurlyBrace)) {
                expr = this.inlineInterface();
+            } else if (this.match(TokenKind.LeftParen)) {
+                let left = this.previous();


This type expression is a GroupingExpression, eg. (integer or float)

Would this github comment be better served as an actual in-code comment?

src/types/UnionType.ts

…amic members

src/astUtils/reflection.ts

markwpearce · 2026-01-13T14:45:50Z

Accomplishes #1330

rokucommunity-bot · 2026-01-20T15:44:17Z

Hey there! I just built a new temporary npm package based on 5e648aa. You can download it here or install it by running the following command:

npm install https://github.com/rokucommunity/brighterscript/releases/download/v0.0.0-packages/brighterscript-1.0.0-alpha.49-intersection-type.20260120154200.tgz

TwitchBronBron

Just a few small things, but overall this looks great!

docs/intersection-types.md

src/astUtils/reflection.ts

TwitchBronBron · 2026-01-20T17:12:18Z

src/astUtils/reflection.ts

 export function isParamTypeFromValueReferenceType(value: any): value is ParamTypeFromValueReferenceType {
    return value?.__reflection?.name === 'ParamTypeFromValueReferenceType';
 }
+export function isIntersectionWithDefaultDynamicReferenceType(value: any): value is IntersectionWithDefaultDynamicReferenceType {


This name is...a lot. 😅 It might be worth adding a comment about what this specific function actually accomplishes. I don't really understand it, even though I can read all the words in its name.

TwitchBronBron · 2026-01-20T17:13:30Z

src/astUtils/reflection.ts


 export function isInheritableType(target): target is InheritableType {
-    return isClassType(target) || isCallFuncableType(target) || isComplexTypeOf(target, isInheritableType);
+    return isClassType(target) || isInterfaceType(target) || isComponentType(target);


Is this a bug? It used to use isComplexType but now is isComponentType. I'm not entirely sure what isInheritableType is used for, but does it allow you to do something like class Alpha extends roSGNodeGroup? (maybe all of this is fine and I'm overthinking it).

Was it actually supposed to be isCompoundType?

It was a bug before.

isInheritableType() is any type that can be extended with extends

TwitchBronBron · 2026-01-20T17:37:28Z

src/parser/Parser.ts

            }
        }
+        if (this.checkAny(TokenKind.And, TokenKind.Or)) {
+            this.warnIfNotBrighterScriptMode('custom types');


Is there a better name than custom types? I know this is configurable, but feels like it would better to say something like intersection or union?

TwitchBronBron · 2026-01-20T17:39:12Z

src/parser/Parser.ts

            if (this.match(TokenKind.LeftCurlyBrace)) {
                expr = this.inlineInterface();
+            } else if (this.match(TokenKind.LeftParen)) {
+                let left = this.previous();


Would this github comment be better served as an actual in-code comment?

rokucommunity-bot · 2026-01-20T17:50:07Z

Hey there! I just built a new temporary npm package based on d277935. You can download it here or install it by running the following command:

npm install https://github.com/rokucommunity/brighterscript/releases/download/v0.0.0-packages/brighterscript-1.0.0-alpha.49-intersection-type.20260120174746.tgz

Co-authored-by: Bronley Plumb <bronley@gmail.com>

rokucommunity-bot · 2026-01-20T18:05:56Z

Hey there! I just built a new temporary npm package based on 92a7755. You can download it here or install it by running the following command:

npm install https://github.com/rokucommunity/brighterscript/releases/download/v0.0.0-packages/brighterscript-1.0.0-alpha.49-intersection-type.20260120180333.tgz

markwpearce added 13 commits December 5, 2025 14:32

wip

0d9745e

Merge branch 'v1' into intersection_type

4849aad

Merge branch 'v1' into intersection_type

a742506

Added IntersectionType tests

8fde59b

Added support for grouped type expressions

48ac3f0

Merge branch 'v1' into intersection_type

a602261

Adding tests for member types of intersection types in scope contexts

723b945

Adds code to handle order of operations when building types

e202859

Adds code to handle order of operations when building types

02ba2bb

removed log statments, started adding validation tests

29022b7

remove .only

6a73946

Better handling of errors - missing right paren on function declratio…

e49662b

…n and using union type in BRS mode

fix lint error

8f72d55

markwpearce commented Jan 5, 2026

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src/parser/Parser.ts Show resolved Hide resolved

markwpearce commented Jan 5, 2026

View reviewed changes

src/types/UnionType.ts Show resolved Hide resolved

markwpearce commented Jan 5, 2026

View reviewed changes

src/types/UnionType.ts Show resolved Hide resolved

markwpearce added 4 commits January 6, 2026 09:31

Adds more validation and compatibility tests for intersections:

e7a8074

Adds new reference type for intersections with types with default dyn…

9305d48

…amic members

Added comment

a7c0f7b

Added docs

b288f8a

markwpearce marked this pull request as ready for review January 12, 2026 20:58

markwpearce added 3 commits January 13, 2026 09:23

Added completion tests

7836adf

Renamed 'ComplexType' -> 'CompoundType'

bbd1bec

More tests for Intersections with order of operations and callfuncs

492e7ad

markwpearce commented Jan 13, 2026

View reviewed changes

src/astUtils/reflection.ts Show resolved Hide resolved

markwpearce added this to the v1.0.0 milestone Jan 13, 2026

Merge branch 'v1' into intersection_type

5e648aa

TwitchBronBron added the create-package create a temporary npm package on every commit label Jan 20, 2026

TwitchBronBron requested changes Jan 20, 2026

View reviewed changes

TwitchBronBron enabled auto-merge (squash) January 20, 2026 17:47

Merge branch 'v1' into intersection_type

d277935

Update docs/intersection-types.md

92a7755

Co-authored-by: Bronley Plumb <bronley@gmail.com>

Intersection Type #1603

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Intersection Type #1603

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markwpearce commented Dec 15, 2025 •

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