More aggressive parens to match existing DT tests

Author: rbuckton

src/compiler/factory/parenthesizerRules.ts

@@ -434,6 +434,7 @@ namespace ts {
         function parenthesizeConstituentTypeOfUnionType(type: TypeNode) {
             switch (type.kind) {
                 case SyntaxKind.UnionType: // Not strictly necessary, but a union containing a union should have been flattened
+                case SyntaxKind.IntersectionType: // Not strictly necessary, but makes generated output more readable and avoids breaks in DT tests
                     return factory.createParenthesizedType(type);
             }
             return parenthesizeCheckTypeOfConditionalType(type);

tests/baselines/reference/controlFlowIfStatement.types

@@ -104,7 +104,7 @@ function c<T>(data: string | T): T {
 >JSON.parse : (text: string, reviver?: (this: any, key: string, value: any) => any) => any
 >JSON : JSON
 >parse : (text: string, reviver?: (this: any, key: string, value: any) => any) => any
->data : string | T & string
+>data : string | (T & string)
     }
     else {
         return data;

tests/baselines/reference/discriminatedUnionTypes2.types

@@ -388,14 +388,14 @@ function foo1(x: RuntimeValue & { type: 'number' }) {
 
 function foo2(x: RuntimeValue & ({ type: 'number' } | { type: 'string' })) {
 >foo2 : (x: RuntimeValue & ({    type: 'number';} | {    type: 'string';})) => void
->x : { type: "number"; value: number; } & { type: 'number'; } | { type: "string"; value: string; } & { type: 'string'; }
+>x : ({ type: "number"; value: number; } & { type: 'number'; }) | ({ type: "string"; value: string; } & { type: 'string'; })
 >type : "number"
 >type : "string"
 
     if (x.type === 'number') {
 >x.type === 'number' : boolean
 >x.type : "string" | "number"
->x : { type: "number"; value: number; } & { type: "number"; } | { type: "string"; value: string; } & { type: "string"; }
+>x : ({ type: "number"; value: number; } & { type: "number"; }) | ({ type: "string"; value: string; } & { type: "string"; })
 >type : "string" | "number"
 >'number' : "number"
 

tests/baselines/reference/intersectionAndUnionTypes.errors.txt

@@ -2,22 +2,22 @@ tests/cases/conformance/types/intersection/intersectionAndUnionTypes.ts(19,1): e
   Property 'b' is missing in type 'A' but required in type 'B'.
 tests/cases/conformance/types/intersection/intersectionAndUnionTypes.ts(20,1): error TS2322: Type 'B' is not assignable to type 'A & B'.
   Property 'a' is missing in type 'B' but required in type 'A'.
-tests/cases/conformance/types/intersection/intersectionAndUnionTypes.ts(23,1): error TS2322: Type 'A | B' is not assignable to type 'A & B | C & D'.
-  Type 'A' is not assignable to type 'A & B | C & D'.
+tests/cases/conformance/types/intersection/intersectionAndUnionTypes.ts(23,1): error TS2322: Type 'A | B' is not assignable to type '(A & B) | (C & D)'.
+  Type 'A' is not assignable to type '(A & B) | (C & D)'.
     Type 'A' is not assignable to type 'A & B'.
-tests/cases/conformance/types/intersection/intersectionAndUnionTypes.ts(25,1): error TS2322: Type 'C | D' is not assignable to type 'A & B | C & D'.
-  Type 'C' is not assignable to type 'A & B | C & D'.
+tests/cases/conformance/types/intersection/intersectionAndUnionTypes.ts(25,1): error TS2322: Type 'C | D' is not assignable to type '(A & B) | (C & D)'.
+  Type 'C' is not assignable to type '(A & B) | (C & D)'.
     Type 'C' is not assignable to type 'C & D'.
       Property 'd' is missing in type 'C' but required in type 'D'.
-tests/cases/conformance/types/intersection/intersectionAndUnionTypes.ts(26,1): error TS2322: Type 'A & B | C & D' is not assignable to type 'A & B'.
+tests/cases/conformance/types/intersection/intersectionAndUnionTypes.ts(26,1): error TS2322: Type '(A & B) | (C & D)' is not assignable to type 'A & B'.
   Type 'C & D' is not assignable to type 'A & B'.
     Property 'a' is missing in type 'C & D' but required in type 'A'.
-tests/cases/conformance/types/intersection/intersectionAndUnionTypes.ts(27,1): error TS2322: Type 'A & B | C & D' is not assignable to type 'A | B'.
+tests/cases/conformance/types/intersection/intersectionAndUnionTypes.ts(27,1): error TS2322: Type '(A & B) | (C & D)' is not assignable to type 'A | B'.
   Type 'C & D' is not assignable to type 'A | B'.
-tests/cases/conformance/types/intersection/intersectionAndUnionTypes.ts(28,1): error TS2322: Type 'A & B | C & D' is not assignable to type 'C & D'.
+tests/cases/conformance/types/intersection/intersectionAndUnionTypes.ts(28,1): error TS2322: Type '(A & B) | (C & D)' is not assignable to type 'C & D'.
   Type 'A & B' is not assignable to type 'C & D'.
     Property 'c' is missing in type 'A & B' but required in type 'C'.
-tests/cases/conformance/types/intersection/intersectionAndUnionTypes.ts(29,1): error TS2322: Type 'A & B | C & D' is not assignable to type 'C | D'.
+tests/cases/conformance/types/intersection/intersectionAndUnionTypes.ts(29,1): error TS2322: Type '(A & B) | (C & D)' is not assignable to type 'C | D'.
   Type 'A & B' is not assignable to type 'C | D'.
 tests/cases/conformance/types/intersection/intersectionAndUnionTypes.ts(31,1): error TS2322: Type 'A & B' is not assignable to type '(A | B) & (C | D)'.
   Type 'A & B' is not assignable to type 'B & D'.
@@ -74,36 +74,36 @@ tests/cases/conformance/types/intersection/intersectionAndUnionTypes.ts(37,1): e
     x = anb;  // Ok
     x = aob;
     ~
-!!! error TS2322: Type 'A | B' is not assignable to type 'A & B | C & D'.
-!!! error TS2322:   Type 'A' is not assignable to type 'A & B | C & D'.
+!!! error TS2322: Type 'A | B' is not assignable to type '(A & B) | (C & D)'.
+!!! error TS2322:   Type 'A' is not assignable to type '(A & B) | (C & D)'.
 !!! error TS2322:     Type 'A' is not assignable to type 'A & B'.
     x = cnd;  // Ok
     x = cod;
     ~
-!!! error TS2322: Type 'C | D' is not assignable to type 'A & B | C & D'.
-!!! error TS2322:   Type 'C' is not assignable to type 'A & B | C & D'.
+!!! error TS2322: Type 'C | D' is not assignable to type '(A & B) | (C & D)'.
+!!! error TS2322:   Type 'C' is not assignable to type '(A & B) | (C & D)'.
 !!! error TS2322:     Type 'C' is not assignable to type 'C & D'.
 !!! error TS2322:       Property 'd' is missing in type 'C' but required in type 'D'.
 !!! related TS2728 tests/cases/conformance/types/intersection/intersectionAndUnionTypes.ts:4:15: 'd' is declared here.
     anb = x;
     ~~~
-!!! error TS2322: Type 'A & B | C & D' is not assignable to type 'A & B'.
+!!! error TS2322: Type '(A & B) | (C & D)' is not assignable to type 'A & B'.
 !!! error TS2322:   Type 'C & D' is not assignable to type 'A & B'.
 !!! error TS2322:     Property 'a' is missing in type 'C & D' but required in type 'A'.
 !!! related TS2728 tests/cases/conformance/types/intersection/intersectionAndUnionTypes.ts:1:15: 'a' is declared here.
     aob = x;
     ~~~
-!!! error TS2322: Type 'A & B | C & D' is not assignable to type 'A | B'.
+!!! error TS2322: Type '(A & B) | (C & D)' is not assignable to type 'A | B'.
 !!! error TS2322:   Type 'C & D' is not assignable to type 'A | B'.
     cnd = x;
     ~~~
-!!! error TS2322: Type 'A & B | C & D' is not assignable to type 'C & D'.
+!!! error TS2322: Type '(A & B) | (C & D)' is not assignable to type 'C & D'.
 !!! error TS2322:   Type 'A & B' is not assignable to type 'C & D'.
 !!! error TS2322:     Property 'c' is missing in type 'A & B' but required in type 'C'.
 !!! related TS2728 tests/cases/conformance/types/intersection/intersectionAndUnionTypes.ts:3:15: 'c' is declared here.
     cod = x;
     ~~~
-!!! error TS2322: Type 'A & B | C & D' is not assignable to type 'C | D'.
+!!! error TS2322: Type '(A & B) | (C & D)' is not assignable to type 'C | D'.
 !!! error TS2322:   Type 'A & B' is not assignable to type 'C | D'.
 
     y = anb;

tests/baselines/reference/intersectionAndUnionTypes.types

@@ -36,7 +36,7 @@ var cod: C | D;
 >cod : C | D
 
 var x: A & B | C & D;
->x : A & B | C & D
+>x : (A & B) | (C & D)
 
 var y: (A | B) & (C | D);
 >y : (A | B) & (C | D)
@@ -63,43 +63,43 @@ anb = b;
 
 x = anb;  // Ok
 >x = anb : A & B
->x : A & B | C & D
+>x : (A & B) | (C & D)
 >anb : A & B
 
 x = aob;
 >x = aob : A | B
->x : A & B | C & D
+>x : (A & B) | (C & D)
 >aob : A | B
 
 x = cnd;  // Ok
 >x = cnd : C & D
->x : A & B | C & D
+>x : (A & B) | (C & D)
 >cnd : C & D
 
 x = cod;
 >x = cod : C | D
->x : A & B | C & D
+>x : (A & B) | (C & D)
 >cod : C | D
 
 anb = x;
->anb = x : A & B | C & D
+>anb = x : (A & B) | (C & D)
 >anb : A & B
->x : A & B | C & D
+>x : (A & B) | (C & D)
 
 aob = x;
->aob = x : A & B | C & D
+>aob = x : (A & B) | (C & D)
 >aob : A | B
->x : A & B | C & D
+>x : (A & B) | (C & D)
 
 cnd = x;
->cnd = x : A & B | C & D
+>cnd = x : (A & B) | (C & D)
 >cnd : C & D
->x : A & B | C & D
+>x : (A & B) | (C & D)
 
 cod = x;
->cod = x : A & B | C & D
+>cod = x : (A & B) | (C & D)
 >cod : C | D
->x : A & B | C & D
+>x : (A & B) | (C & D)
 
 y = anb;
 >y = anb : A & B

tests/baselines/reference/intersectionNarrowing.types

@@ -2,24 +2,24 @@
 // Repros from #43130
 
 function f1<T>(x: T & string | T & undefined) {
->f1 : <T>(x: T & string | T & undefined) => void
->x : T & string | T & undefined
+>f1 : <T>(x: (T & string) | (T & undefined)) => void
+>x : (T & string) | (T & undefined)
 
     if (x) {
->x : T & string | T & undefined
+>x : (T & string) | (T & undefined)
 
         x;  // Should narrow to T & string
 >x : T & string
     }
 }
 
 function f2<T>(x: T & string | T & undefined) {
->f2 : <T>(x: T & string | T & undefined) => void
->x : T & string | T & undefined
+>f2 : <T>(x: (T & string) | (T & undefined)) => void
+>x : (T & string) | (T & undefined)
 
     if (x !== undefined) {
 >x !== undefined : boolean
->x : T & string | T & undefined
+>x : (T & string) | (T & undefined)
 >undefined : undefined
 
         x;  // Should narrow to T & string
@@ -32,13 +32,13 @@ function f2<T>(x: T & string | T & undefined) {
 }
 
 function f3<T>(x: T & string | T & number) {
->f3 : <T>(x: T & string | T & number) => void
->x : T & string | T & number
+>f3 : <T>(x: (T & string) | (T & number)) => void
+>x : (T & string) | (T & number)
 
     if (typeof x === "string") {
 >typeof x === "string" : boolean
 >typeof x : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
->x : T & string | T & number
+>x : (T & string) | (T & number)
 >"string" : "string"
 
         x;  // Should narrow to T & string
@@ -51,11 +51,11 @@ function f3<T>(x: T & string | T & number) {
 }
 
 function f4<T>(x: T & 1 | T & 2) {
->f4 : <T>(x: T & 1 | T & 2) => void
->x : T & 1 | T & 2
+>f4 : <T>(x: (T & 1) | (T & 2)) => void
+>x : (T & 1) | (T & 2)
 
     switch (x) {
->x : T & 1 | T & 2
+>x : (T & 1) | (T & 2)
 
         case 1: x; break;  // T & 1
 >1 : 1

tests/baselines/reference/intersectionOfUnionNarrowing.types

@@ -20,9 +20,9 @@ declare const q: X & AorB;
 
 if (q.a !== undefined) {
 >q.a !== undefined : boolean
->q.a : { aProp: string; } & object | undefined
+>q.a : ({ aProp: string; } & object) | undefined
 >q : X & AorB
->a : { aProp: string; } & object | undefined
+>a : ({ aProp: string; } & object) | undefined
 >undefined : undefined
 
   q.a.aProp;

tests/baselines/reference/keyofAndIndexedAccess2.types

@@ -564,7 +564,7 @@ for (const action of actions) {
 
 		window[action](x, y);
 >window[action](x, y) : void
->window[action] : ((x: number, y: number) => void) & ((x: number, y: number) => void) | ((width: number, height: number) => void) & ((width: number, height: number) => void)
+>window[action] : (((x: number, y: number) => void) & ((x: number, y: number) => void)) | (((width: number, height: number) => void) & ((width: number, height: number) => void))
 >window : Window & typeof globalThis
 >action : "resizeTo" | "resizeBy"
 >x : number

tests/baselines/reference/narrowingByTypeofInSwitch.types

@@ -564,8 +564,8 @@ function multipleGenericFuse<X extends L | number, Y extends R | number>(xy: X |
 
         case 'number': return [xy]
 >'number' : "number"
->[xy] : [X & number | Y & number]
->xy : X & number | Y & number
+>[xy] : [(X & number) | (Y & number)]
+>xy : (X & number) | (Y & number)
     }
 }
 
@@ -1104,8 +1104,8 @@ function multipleGenericFuseWithBoth<X extends L | number, Y extends R | number>
 
         case `number`: return [xy]
 >`number` : "number"
->[xy] : [X & number | Y & number]
->xy : X & number | Y & number
+>[xy] : [(X & number) | (Y & number)]
+>xy : (X & number) | (Y & number)
     }
 }
 

tests/baselines/reference/narrowingTypeofFunction.types

@@ -7,12 +7,12 @@ interface F { (): string }
 
 function f1(a: (F & Meta) | string) {
 >f1 : (a: (F & Meta) | string) => void
->a : string | F & Meta
+>a : string | (F & Meta)
 
     if (typeof a === "function") {
 >typeof a === "function" : boolean
 >typeof a : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
->a : string | F & Meta
+>a : string | (F & Meta)
 >"function" : "function"
 
         a;
@@ -25,17 +25,17 @@ function f1(a: (F & Meta) | string) {
 }
 
 function f2<T>(x: (T & F) | T & string) {
->f2 : <T>(x: (T & F) | T & string) => void
->x : T & F | T & string
+>f2 : <T>(x: (T & F) | (T & string)) => void
+>x : (T & F) | (T & string)
 
     if (typeof x === "function") {
 >typeof x === "function" : boolean
 >typeof x : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
->x : T & F | T & string
+>x : (T & F) | (T & string)
 >"function" : "function"
 
         x;
->x : T & F | T & string
+>x : (T & F) | (T & string)
     }
     else {
         x;