Merge pull request #31400 from microsoft/undoSubsitutionSimplification

ahejlsberg · web-flow · commit 922186834fd5 · 2019-05-14T22:58:14.000-07:00
Revert substitution type simplification
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -10196,7 +10196,6 @@ namespace ts {
         function getSimplifiedType(type: Type, writing: boolean): Type {
             return type.flags & TypeFlags.IndexedAccess ? getSimplifiedIndexedAccessType(<IndexedAccessType>type, writing) :
                 type.flags & TypeFlags.Conditional ? getSimplifiedConditionalType(<ConditionalType>type, writing) :
-                type.flags & TypeFlags.Substitution ? writing ? (<SubstitutionType>type).typeVariable : (<SubstitutionType>type).substitute :
                 type;
         }
 
@@ -12432,6 +12431,12 @@ namespace ts {
                 if (isFreshLiteralType(target)) {
                     target = (<FreshableType>target).regularType;
                 }
+                if (source.flags & TypeFlags.Substitution) {
+                    source = (<SubstitutionType>source).substitute;
+                }
+                if (target.flags & TypeFlags.Substitution) {
+                    target = (<SubstitutionType>target).typeVariable;
+                }
                 if (source.flags & TypeFlags.Simplifiable) {
                     source = getSimplifiedType(source, /*writing*/ false);
                 }
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
@@ -3967,7 +3967,7 @@ namespace ts {
         /* @internal */
         ObjectFlagsType = Nullable | Never | Object | Union | Intersection,
         /* @internal */
-        Simplifiable = IndexedAccess | Conditional | Substitution,
+        Simplifiable = IndexedAccess | Conditional,
         // 'Narrowable' types are types where narrowing actually narrows.
         // This *should* be every type other than null, undefined, void, and never
         Narrowable = Any | Unknown | StructuredOrInstantiable | StringLike | NumberLike | BigIntLike | BooleanLike | ESSymbol | UniqueESSymbol | NonPrimitive,
diff --git a/tests/baselines/reference/conditionalTypes2.errors.txt b/tests/baselines/reference/conditionalTypes2.errors.txt
@@ -10,13 +10,13 @@ tests/cases/conformance/types/conditional/conditionalTypes2.ts(24,5): error TS23
       Type 'keyof B' is not assignable to type 'keyof A'.
         Type 'string | number | symbol' is not assignable to type 'keyof A'.
           Type 'string' is not assignable to type 'keyof A'.
-            Type 'string' is not assignable to type 'number | "toString" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "length" | "substr" | "valueOf" | keyof A'.
-              Type 'keyof B' is not assignable to type 'number | "toString" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "length" | "substr" | "valueOf" | keyof A'.
-                Type 'string | number | symbol' is not assignable to type 'number | "toString" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "length" | "substr" | "valueOf" | keyof A'.
-                  Type 'string' is not assignable to type 'number | "toString" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "length" | "substr" | "valueOf" | keyof A'.
-                    Type 'keyof B' is not assignable to type 'keyof A'.
-                      Type 'string | number | symbol' is not assignable to type 'keyof A'.
-                        Type 'string' is not assignable to type 'keyof A'.
+            Type 'string' is not assignable to type 'number | "toString" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "length" | "substr" | "valueOf"'.
+              Type 'keyof B' is not assignable to type 'number | "toString" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "length" | "substr" | "valueOf"'.
+                Type 'string | number | symbol' is not assignable to type 'number | "toString" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "length" | "substr" | "valueOf"'.
+                  Type 'string' is not assignable to type 'number | "toString" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "length" | "substr" | "valueOf"'.
+                    Type 'keyof B' is not assignable to type '"valueOf"'.
+                      Type 'string | number | symbol' is not assignable to type '"valueOf"'.
+                        Type 'string' is not assignable to type '"valueOf"'.
 tests/cases/conformance/types/conditional/conditionalTypes2.ts(25,5): error TS2322: Type 'Invariant<A>' is not assignable to type 'Invariant<B>'.
   Types of property 'foo' are incompatible.
     Type 'A extends string ? keyof A : A' is not assignable to type 'B extends string ? keyof B : B'.
@@ -73,13 +73,13 @@ tests/cases/conformance/types/conditional/conditionalTypes2.ts(75,12): error TS2
 !!! error TS2322:       Type 'keyof B' is not assignable to type 'keyof A'.
 !!! error TS2322:         Type 'string | number | symbol' is not assignable to type 'keyof A'.
 !!! error TS2322:           Type 'string' is not assignable to type 'keyof A'.
-!!! error TS2322:             Type 'string' is not assignable to type 'number | "toString" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "length" | "substr" | "valueOf" | keyof A'.
-!!! error TS2322:               Type 'keyof B' is not assignable to type 'number | "toString" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "length" | "substr" | "valueOf" | keyof A'.
-!!! error TS2322:                 Type 'string | number | symbol' is not assignable to type 'number | "toString" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "length" | "substr" | "valueOf" | keyof A'.
-!!! error TS2322:                   Type 'string' is not assignable to type 'number | "toString" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "length" | "substr" | "valueOf" | keyof A'.
-!!! error TS2322:                     Type 'keyof B' is not assignable to type 'keyof A'.
-!!! error TS2322:                       Type 'string | number | symbol' is not assignable to type 'keyof A'.
-!!! error TS2322:                         Type 'string' is not assignable to type 'keyof A'.
+!!! error TS2322:             Type 'string' is not assignable to type 'number | "toString" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "length" | "substr" | "valueOf"'.
+!!! error TS2322:               Type 'keyof B' is not assignable to type 'number | "toString" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "length" | "substr" | "valueOf"'.
+!!! error TS2322:                 Type 'string | number | symbol' is not assignable to type 'number | "toString" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "length" | "substr" | "valueOf"'.
+!!! error TS2322:                   Type 'string' is not assignable to type 'number | "toString" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "length" | "substr" | "valueOf"'.
+!!! error TS2322:                     Type 'keyof B' is not assignable to type '"valueOf"'.
+!!! error TS2322:                       Type 'string | number | symbol' is not assignable to type '"valueOf"'.
+!!! error TS2322:                         Type 'string' is not assignable to type '"valueOf"'.
         b = a;  // Error
         ~
 !!! error TS2322: Type 'Invariant<A>' is not assignable to type 'Invariant<B>'.

Original file line number	Diff line number	Diff line change
`@@ -10196,7 +10196,6 @@ namespace ts {`
`10196`	`10196`	`function getSimplifiedType(type: Type, writing: boolean): Type {`
`10197`	`10197`	`return type.flags & TypeFlags.IndexedAccess ? getSimplifiedIndexedAccessType(<IndexedAccessType>type, writing) :`
`10198`	`10198`	`type.flags & TypeFlags.Conditional ? getSimplifiedConditionalType(<ConditionalType>type, writing) :`
`10199`		`- type.flags & TypeFlags.Substitution ? writing ? (<SubstitutionType>type).typeVariable : (<SubstitutionType>type).substitute :`
`10200`	`10199`	`type;`
`10201`	`10200`	`}`
`10202`	`10201`
`@@ -12432,6 +12431,12 @@ namespace ts {`
`12432`	`12431`	`if (isFreshLiteralType(target)) {`
`12433`	`12432`	`target = (<FreshableType>target).regularType;`
`12434`	`12433`	`}`
	`12434`	`+ if (source.flags & TypeFlags.Substitution) {`
	`12435`	`+ source = (<SubstitutionType>source).substitute;`
	`12436`	`+ }`
	`12437`	`+ if (target.flags & TypeFlags.Substitution) {`
	`12438`	`+ target = (<SubstitutionType>target).typeVariable;`
	`12439`	`+ }`
`12435`	`12440`	`if (source.flags & TypeFlags.Simplifiable) {`
`12436`	`12441`	`source = getSimplifiedType(source, /writing/ false);`
`12437`	`12442`	`}`