Fix crash when @augments tag has no type (#18739)

src/compiler/checker.ts

@@ -4990,7 +4990,7 @@ namespace ts {
             const valueDecl = type.symbol.valueDeclaration;
             if (valueDecl && isInJavaScriptFile(valueDecl)) {
                 const augTag = getJSDocAugmentsTag(type.symbol.valueDeclaration);
-                if (augTag) {
+                if (augTag && augTag.typeExpression && augTag.typeExpression.type) {
                     baseType = getTypeFromTypeNode(augTag.typeExpression.type);
                 }
             }

tests/baselines/reference/jsdocAugmentsMissingType.errors.txt

@@ -0,0 +1,14 @@
+/a.js(2,14): error TS1005: '{' expected.
+
+
+==== /a.js (1 errors) ====
+    class A { constructor() { this.x = 0; } }
+    /** @augments */
+                 ~
+!!! error TS1005: '{' expected.
+    class B extends A {
+        m() {
+            this.x
+        }
+    }
+    

tests/baselines/reference/jsdocAugmentsMissingType.symbols

@@ -0,0 +1,22 @@
+=== /a.js ===
+class A { constructor() { this.x = 0; } }
+>A : Symbol(A, Decl(a.js, 0, 0))
+>this.x : Symbol(A.x, Decl(a.js, 0, 25))
+>this : Symbol(A, Decl(a.js, 0, 0))
+>x : Symbol(A.x, Decl(a.js, 0, 25))
+
+/** @augments */
+class B extends A {
+>B : Symbol(B, Decl(a.js, 0, 41))
+>A : Symbol(A, Decl(a.js, 0, 0))
+
+    m() {
+>m : Symbol(B.m, Decl(a.js, 2, 19))
+
+        this.x
+>this.x : Symbol(A.x, Decl(a.js, 0, 25))
+>this : Symbol(B, Decl(a.js, 0, 41))
+>x : Symbol(A.x, Decl(a.js, 0, 25))
+    }
+}
+

tests/baselines/reference/jsdocAugmentsMissingType.types

@@ -0,0 +1,24 @@
+=== /a.js ===
+class A { constructor() { this.x = 0; } }
+>A : A
+>this.x = 0 : 0
+>this.x : number
+>this : this
+>x : number
+>0 : 0
+
+/** @augments */
+class B extends A {
+>B : B
+>A : A
+
+    m() {
+>m : () => void
+
+        this.x
+>this.x : number
+>this : this
+>x : number
+    }
+}
+

tests/cases/compiler/jsdocAugmentsMissingType.ts

@@ -0,0 +1,12 @@
+// @allowJs: true
+// @checkJs: true
+// @noEmit: true
+
+// @Filename: /a.js
+class A { constructor() { this.x = 0; } }
+/** @augments */
+class B extends A {
+    m() {
+        this.x
+    }
+}