narrow type for generic variables inside TypeQuery (#48434)

Zzzen · web-flow · commit 370d34cdca7e · 2022-04-05T09:33:19.000-07:00
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -25311,6 +25311,7 @@ namespace ts {
             // a generic type without a nullable constraint and x is a generic type. This is because when both obj
             // and x are of generic types T and K, we want the resulting type to be T[K].
             return parent.kind === SyntaxKind.PropertyAccessExpression ||
+                parent.kind === SyntaxKind.QualifiedName ||
                 parent.kind === SyntaxKind.CallExpression && (parent as CallExpression).expression === node ||
                 parent.kind === SyntaxKind.ElementAccessExpression && (parent as ElementAccessExpression).expression === node &&
                     !(someType(type, isGenericTypeWithoutNullableConstraint) && isGenericIndexType(getTypeOfExpression((parent as ElementAccessExpression).argumentExpression)));
diff --git a/tests/baselines/reference/narrowingOfQualifiedNames.errors.txt b/tests/baselines/reference/narrowingOfQualifiedNames.errors.txt
@@ -71,4 +71,25 @@ tests/cases/compiler/narrowingOfQualifiedNames.ts(38,29): error TS2532: Object i
                 }
             }
         }
+    }
+    
+    // Repro from #48289
+    
+    type Fish = { type: 'fish', hasFins: true }
+    type Dog = { type: 'dog', saysWoof: true }
+    
+    type Pet = Fish | Dog;
+    
+    function handleDogBroken<PetType extends Pet>(pet: PetType) {
+        if(pet.type === 'dog') {
+            const _okay1 = pet.saysWoof;
+            const _okay2: typeof pet.saysWoof = pet.saysWoof;
+        }
+    }
+    
+    function handleDogWorking(pet: Pet) {
+        if(pet.type === 'dog') {
+            const _okay1 = pet.saysWoof;
+            const _okay2: typeof pet.saysWoof = pet.saysWoof;
+        }
     }
diff --git a/tests/baselines/reference/narrowingOfQualifiedNames.js b/tests/baselines/reference/narrowingOfQualifiedNames.js
@@ -63,6 +63,27 @@ function init2(foo: DeepOptional) {
             }
         }
     }
+}
+
+// Repro from #48289
+
+type Fish = { type: 'fish', hasFins: true }
+type Dog = { type: 'dog', saysWoof: true }
+
+type Pet = Fish | Dog;
+
+function handleDogBroken<PetType extends Pet>(pet: PetType) {
+    if(pet.type === 'dog') {
+        const _okay1 = pet.saysWoof;
+        const _okay2: typeof pet.saysWoof = pet.saysWoof;
+    }
+}
+
+function handleDogWorking(pet: Pet) {
+    if(pet.type === 'dog') {
+        const _okay1 = pet.saysWoof;
+        const _okay2: typeof pet.saysWoof = pet.saysWoof;
+    }
 }
 
 //// [narrowingOfQualifiedNames.js]
@@ -94,3 +115,15 @@ function init2(foo) {
         }
     }
 }
+function handleDogBroken(pet) {
+    if (pet.type === 'dog') {
+        var _okay1 = pet.saysWoof;
+        var _okay2 = pet.saysWoof;
+    }
+}
+function handleDogWorking(pet) {
+    if (pet.type === 'dog') {
+        var _okay1 = pet.saysWoof;
+        var _okay2 = pet.saysWoof;
+    }
+}
diff --git a/tests/baselines/reference/narrowingOfQualifiedNames.symbols b/tests/baselines/reference/narrowingOfQualifiedNames.symbols
@@ -253,3 +253,76 @@ function init2(foo: DeepOptional) {
         }
     }
 }
+
+// Repro from #48289
+
+type Fish = { type: 'fish', hasFins: true }
+>Fish : Symbol(Fish, Decl(narrowingOfQualifiedNames.ts, 64, 1))
+>type : Symbol(type, Decl(narrowingOfQualifiedNames.ts, 68, 13))
+>hasFins : Symbol(hasFins, Decl(narrowingOfQualifiedNames.ts, 68, 27))
+
+type Dog = { type: 'dog', saysWoof: true }
+>Dog : Symbol(Dog, Decl(narrowingOfQualifiedNames.ts, 68, 43))
+>type : Symbol(type, Decl(narrowingOfQualifiedNames.ts, 69, 12))
+>saysWoof : Symbol(saysWoof, Decl(narrowingOfQualifiedNames.ts, 69, 25))
+
+type Pet = Fish | Dog;
+>Pet : Symbol(Pet, Decl(narrowingOfQualifiedNames.ts, 69, 42))
+>Fish : Symbol(Fish, Decl(narrowingOfQualifiedNames.ts, 64, 1))
+>Dog : Symbol(Dog, Decl(narrowingOfQualifiedNames.ts, 68, 43))
+
+function handleDogBroken<PetType extends Pet>(pet: PetType) {
+>handleDogBroken : Symbol(handleDogBroken, Decl(narrowingOfQualifiedNames.ts, 71, 22))
+>PetType : Symbol(PetType, Decl(narrowingOfQualifiedNames.ts, 73, 25))
+>Pet : Symbol(Pet, Decl(narrowingOfQualifiedNames.ts, 69, 42))
+>pet : Symbol(pet, Decl(narrowingOfQualifiedNames.ts, 73, 46))
+>PetType : Symbol(PetType, Decl(narrowingOfQualifiedNames.ts, 73, 25))
+
+    if(pet.type === 'dog') {
+>pet.type : Symbol(type, Decl(narrowingOfQualifiedNames.ts, 68, 13), Decl(narrowingOfQualifiedNames.ts, 69, 12))
+>pet : Symbol(pet, Decl(narrowingOfQualifiedNames.ts, 73, 46))
+>type : Symbol(type, Decl(narrowingOfQualifiedNames.ts, 68, 13), Decl(narrowingOfQualifiedNames.ts, 69, 12))
+
+        const _okay1 = pet.saysWoof;
+>_okay1 : Symbol(_okay1, Decl(narrowingOfQualifiedNames.ts, 75, 13))
+>pet.saysWoof : Symbol(saysWoof, Decl(narrowingOfQualifiedNames.ts, 69, 25))
+>pet : Symbol(pet, Decl(narrowingOfQualifiedNames.ts, 73, 46))
+>saysWoof : Symbol(saysWoof, Decl(narrowingOfQualifiedNames.ts, 69, 25))
+
+        const _okay2: typeof pet.saysWoof = pet.saysWoof;
+>_okay2 : Symbol(_okay2, Decl(narrowingOfQualifiedNames.ts, 76, 13))
+>pet.saysWoof : Symbol(saysWoof, Decl(narrowingOfQualifiedNames.ts, 69, 25))
+>pet : Symbol(pet, Decl(narrowingOfQualifiedNames.ts, 73, 46))
+>saysWoof : Symbol(saysWoof, Decl(narrowingOfQualifiedNames.ts, 69, 25))
+>pet.saysWoof : Symbol(saysWoof, Decl(narrowingOfQualifiedNames.ts, 69, 25))
+>pet : Symbol(pet, Decl(narrowingOfQualifiedNames.ts, 73, 46))
+>saysWoof : Symbol(saysWoof, Decl(narrowingOfQualifiedNames.ts, 69, 25))
+    }
+}
+
+function handleDogWorking(pet: Pet) {
+>handleDogWorking : Symbol(handleDogWorking, Decl(narrowingOfQualifiedNames.ts, 78, 1))
+>pet : Symbol(pet, Decl(narrowingOfQualifiedNames.ts, 80, 26))
+>Pet : Symbol(Pet, Decl(narrowingOfQualifiedNames.ts, 69, 42))
+
+    if(pet.type === 'dog') {
+>pet.type : Symbol(type, Decl(narrowingOfQualifiedNames.ts, 68, 13), Decl(narrowingOfQualifiedNames.ts, 69, 12))
+>pet : Symbol(pet, Decl(narrowingOfQualifiedNames.ts, 80, 26))
+>type : Symbol(type, Decl(narrowingOfQualifiedNames.ts, 68, 13), Decl(narrowingOfQualifiedNames.ts, 69, 12))
+
+        const _okay1 = pet.saysWoof;
+>_okay1 : Symbol(_okay1, Decl(narrowingOfQualifiedNames.ts, 82, 13))
+>pet.saysWoof : Symbol(saysWoof, Decl(narrowingOfQualifiedNames.ts, 69, 25))
+>pet : Symbol(pet, Decl(narrowingOfQualifiedNames.ts, 80, 26))
+>saysWoof : Symbol(saysWoof, Decl(narrowingOfQualifiedNames.ts, 69, 25))
+
+        const _okay2: typeof pet.saysWoof = pet.saysWoof;
+>_okay2 : Symbol(_okay2, Decl(narrowingOfQualifiedNames.ts, 83, 13))
+>pet.saysWoof : Symbol(saysWoof, Decl(narrowingOfQualifiedNames.ts, 69, 25))
+>pet : Symbol(pet, Decl(narrowingOfQualifiedNames.ts, 80, 26))
+>saysWoof : Symbol(saysWoof, Decl(narrowingOfQualifiedNames.ts, 69, 25))
+>pet.saysWoof : Symbol(saysWoof, Decl(narrowingOfQualifiedNames.ts, 69, 25))
+>pet : Symbol(pet, Decl(narrowingOfQualifiedNames.ts, 80, 26))
+>saysWoof : Symbol(saysWoof, Decl(narrowingOfQualifiedNames.ts, 69, 25))
+    }
+}
diff --git a/tests/baselines/reference/narrowingOfQualifiedNames.types b/tests/baselines/reference/narrowingOfQualifiedNames.types
@@ -257,3 +257,76 @@ function init2(foo: DeepOptional) {
         }
     }
 }
+
+// Repro from #48289
+
+type Fish = { type: 'fish', hasFins: true }
+>Fish : Fish
+>type : "fish"
+>hasFins : true
+>true : true
+
+type Dog = { type: 'dog', saysWoof: true }
+>Dog : Dog
+>type : "dog"
+>saysWoof : true
+>true : true
+
+type Pet = Fish | Dog;
+>Pet : Pet
+
+function handleDogBroken<PetType extends Pet>(pet: PetType) {
+>handleDogBroken : <PetType extends Pet>(pet: PetType) => void
+>pet : PetType
+
+    if(pet.type === 'dog') {
+>pet.type === 'dog' : boolean
+>pet.type : "fish" | "dog"
+>pet : Pet
+>type : "fish" | "dog"
+>'dog' : "dog"
+
+        const _okay1 = pet.saysWoof;
+>_okay1 : true
+>pet.saysWoof : true
+>pet : Dog
+>saysWoof : true
+
+        const _okay2: typeof pet.saysWoof = pet.saysWoof;
+>_okay2 : true
+>pet.saysWoof : true
+>pet : Dog
+>saysWoof : true
+>pet.saysWoof : true
+>pet : Dog
+>saysWoof : true
+    }
+}
+
+function handleDogWorking(pet: Pet) {
+>handleDogWorking : (pet: Pet) => void
+>pet : Pet
+
+    if(pet.type === 'dog') {
+>pet.type === 'dog' : boolean
+>pet.type : "fish" | "dog"
+>pet : Pet
+>type : "fish" | "dog"
+>'dog' : "dog"
+
+        const _okay1 = pet.saysWoof;
+>_okay1 : true
+>pet.saysWoof : true
+>pet : Dog
+>saysWoof : true
+
+        const _okay2: typeof pet.saysWoof = pet.saysWoof;
+>_okay2 : true
+>pet.saysWoof : true
+>pet : Dog
+>saysWoof : true
+>pet.saysWoof : true
+>pet : Dog
+>saysWoof : true
+    }
+}
diff --git a/tests/cases/compiler/narrowingOfQualifiedNames.ts b/tests/cases/compiler/narrowingOfQualifiedNames.ts
@@ -64,4 +64,25 @@ function init2(foo: DeepOptional) {
             }
         }
     }
+}
+
+// Repro from #48289
+
+type Fish = { type: 'fish', hasFins: true }
+type Dog = { type: 'dog', saysWoof: true }
+
+type Pet = Fish | Dog;
+
+function handleDogBroken<PetType extends Pet>(pet: PetType) {
+    if(pet.type === 'dog') {
+        const _okay1 = pet.saysWoof;
+        const _okay2: typeof pet.saysWoof = pet.saysWoof;
+    }
+}
+
+function handleDogWorking(pet: Pet) {
+    if(pet.type === 'dog') {
+        const _okay1 = pet.saysWoof;
+        const _okay2: typeof pet.saysWoof = pet.saysWoof;
+    }
 }
