check return tag in getTypePredicateOfSignature

src/compiler/checker.ts

@@ -7538,9 +7538,9 @@ namespace ts {
                     signature.resolvedTypePredicate = getUnionTypePredicate(signature.unionSignatures) || noTypePredicate;
                 }
                 else {
-                    const declaration = signature.declaration;
-                    signature.resolvedTypePredicate = declaration && declaration.type && declaration.type.kind === SyntaxKind.TypePredicate ?
-                        createTypePredicateFromTypePredicateNode(declaration.type as TypePredicateNode) :
+                    const type = signature.declaration && getEffectiveReturnTypeNode(signature.declaration);
+                    signature.resolvedTypePredicate = type && isTypePredicateNode(type) ?
+                        createTypePredicateFromTypePredicateNode(type) :
                         noTypePredicate;
                 }
                 Debug.assert(!!signature.resolvedTypePredicate);

tests/baselines/reference/returnTagTypeGuard.symbols

@@ -0,0 +1,63 @@
+=== tests/cases/conformance/jsdoc/bug25127.js ===
+class Entry {
+>Entry : Symbol(Entry, Decl(bug25127.js, 0, 0))
+
+    constructor() {
+        this.c = 1
+>this.c : Symbol(Entry.c, Decl(bug25127.js, 1, 19))
+>this : Symbol(Entry, Decl(bug25127.js, 0, 0))
+>c : Symbol(Entry.c, Decl(bug25127.js, 1, 19))
+    }
+    /**
+     * @param {any} x
+     * @return {this is Entry}
+     */
+    isInit(x) {
+>isInit : Symbol(Entry.isInit, Decl(bug25127.js, 3, 5))
+>x : Symbol(x, Decl(bug25127.js, 8, 11))
+
+        return true
+    }
+}
+class Group {
+>Group : Symbol(Group, Decl(bug25127.js, 11, 1))
+
+    constructor() {
+        this.d = 'no'
+>this.d : Symbol(Group.d, Decl(bug25127.js, 13, 19))
+>this : Symbol(Group, Decl(bug25127.js, 11, 1))
+>d : Symbol(Group.d, Decl(bug25127.js, 13, 19))
+    }
+    /**
+     * @param {any} x
+     * @return {false}
+     */
+    isInit(x) {
+>isInit : Symbol(Group.isInit, Decl(bug25127.js, 15, 5))
+>x : Symbol(x, Decl(bug25127.js, 20, 11))
+
+        return false
+    }
+}
+/** @param {Entry | Group} chunk */
+function f(chunk) {
+>f : Symbol(f, Decl(bug25127.js, 23, 1))
+>chunk : Symbol(chunk, Decl(bug25127.js, 25, 11))
+
+    let x = chunk.isInit(chunk) ? chunk.c : chunk.d
+>x : Symbol(x, Decl(bug25127.js, 26, 7))
+>chunk.isInit : Symbol(isInit, Decl(bug25127.js, 3, 5), Decl(bug25127.js, 15, 5))
+>chunk : Symbol(chunk, Decl(bug25127.js, 25, 11))
+>isInit : Symbol(isInit, Decl(bug25127.js, 3, 5), Decl(bug25127.js, 15, 5))
+>chunk : Symbol(chunk, Decl(bug25127.js, 25, 11))
+>chunk.c : Symbol(Entry.c, Decl(bug25127.js, 1, 19))
+>chunk : Symbol(chunk, Decl(bug25127.js, 25, 11))
+>c : Symbol(Entry.c, Decl(bug25127.js, 1, 19))
+>chunk.d : Symbol(Group.d, Decl(bug25127.js, 13, 19))
+>chunk : Symbol(chunk, Decl(bug25127.js, 25, 11))
+>d : Symbol(Group.d, Decl(bug25127.js, 13, 19))
+
+    return x
+>x : Symbol(x, Decl(bug25127.js, 26, 7))
+}
+

tests/baselines/reference/returnTagTypeGuard.types

@@ -0,0 +1,71 @@
+=== tests/cases/conformance/jsdoc/bug25127.js ===
+class Entry {
+>Entry : Entry
+
+    constructor() {
+        this.c = 1
+>this.c = 1 : 1
+>this.c : number
+>this : this
+>c : number
+>1 : 1
+    }
+    /**
+     * @param {any} x
+     * @return {this is Entry}
+     */
+    isInit(x) {
+>isInit : (x: any) => this is Entry
+>x : any
+
+        return true
+>true : true
+    }
+}
+class Group {
+>Group : Group
+
+    constructor() {
+        this.d = 'no'
+>this.d = 'no' : "no"
+>this.d : string
+>this : this
+>d : string
+>'no' : "no"
+    }
+    /**
+     * @param {any} x
+     * @return {false}
+     */
+    isInit(x) {
+>isInit : (x: any) => false
+>x : any
+
+        return false
+>false : false
+    }
+}
+/** @param {Entry | Group} chunk */
+function f(chunk) {
+>f : (chunk: Entry | Group) => string | number
+>chunk : Entry | Group
+
+    let x = chunk.isInit(chunk) ? chunk.c : chunk.d
+>x : string | number
+>chunk.isInit(chunk) ? chunk.c : chunk.d : string | number
+>chunk.isInit(chunk) : boolean
+>chunk.isInit : ((x: any) => this is Entry) | ((x: any) => false)
+>chunk : Entry | Group
+>isInit : ((x: any) => this is Entry) | ((x: any) => false)
+>chunk : Entry | Group
+>chunk.c : number
+>chunk : Entry
+>c : number
+>chunk.d : string
+>chunk : Group
+>d : string
+
+    return x
+>x : string | number
+}
+

tests/cases/conformance/jsdoc/returnTagTypeGuard.ts

@@ -0,0 +1,34 @@
+// @noEmit: true
+// @allowJs: true
+// @checkJs: true
+// @lib: esnext
+// @Filename: bug25127.js
+class Entry {
+    constructor() {
+        this.c = 1
+    }
+    /**
+     * @param {any} x
+     * @return {this is Entry}
+     */
+    isInit(x) {
+        return true
+    }
+}
+class Group {
+    constructor() {
+        this.d = 'no'
+    }
+    /**
+     * @param {any} x
+     * @return {false}
+     */
+    isInit(x) {
+        return false
+    }
+}
+/** @param {Entry | Group} chunk */
+function f(chunk) {
+    let x = chunk.isInit(chunk) ? chunk.c : chunk.d
+    return x
+}