Add index signature for anonymous object literal type

src/compiler/checker.ts

@@ -13660,6 +13660,19 @@ namespace ts {
                     return anyType;
                 }
                 if (accessExpression && !isConstEnumObjectType(objectType)) {
+                    if (isObjectLiteralType(objectType)) {
+                        if (noImplicitAny && indexType.flags & (TypeFlags.StringLiteral | TypeFlags.NumberLiteral)) {
+                            diagnostics.add(createDiagnosticForNode(accessExpression, Diagnostics.Property_0_does_not_exist_on_type_1, (indexType as StringLiteralType).value, typeToString(objectType)));
+                            return undefinedType;
+                        }
+                        else if (indexType.flags & (TypeFlags.Number | TypeFlags.String)) {
+                            const types = map((<ResolvedType>objectType).properties, property => {
+                                return getTypeOfSymbol(property);
+                            });
+                            return getUnionType(append(types, undefinedType));
+                        }
+                    }
+
                     if (objectType.symbol === globalThisSymbol && propName !== undefined && globalThisSymbol.exports!.has(propName) && (globalThisSymbol.exports!.get(propName)!.flags & SymbolFlags.BlockScoped)) {
                         error(accessExpression, Diagnostics.Property_0_does_not_exist_on_type_1, unescapeLeadingUnderscores(propName), typeToString(objectType));
                     }

tests/baselines/reference/indexedAccessWithFreshObjectLiteral.errors.txt

@@ -0,0 +1,64 @@
+tests/cases/compiler/indexedAccessWithFreshObjectLiteral.ts(34,10): error TS2339: Property 'z' does not exist on type '{ a: number; b: string; c: boolean; }'.
+
+
+==== tests/cases/compiler/indexedAccessWithFreshObjectLiteral.ts (1 errors) ====
+    function foo (id: string) {
+      return {
+          a: 1,
+          b: "",
+          c: true
+      }[id]
+    }
+
+    function bar (id: 'a' | 'b') {
+      return {
+          a: 1,
+          b: "",
+          c: false
+      }[id]
+    }
+
+    function baz (id: '1' | '2') {
+      return {
+          1: 1,
+          2: "",
+          3: false
+      }[id]
+    }
+
+    function qux (id: 1 | 2) {
+      return {
+          1: 1,
+          2: "",
+          3: false
+      }[id]
+    }
+
+    function quux (id: 'a' | 'b' | 'z') {
+      return {
+             ~
+          a: 1,
+    ~~~~~~~~~~~
+          b: "",
+    ~~~~~~~~~~~~
+          c: false
+    ~~~~~~~~~~~~~~
+      }[id]
+    ~~~~~~~
+!!! error TS2339: Property 'z' does not exist on type '{ a: number; b: string; c: boolean; }'.
+    }
+
+    function corge(id: string) {
+      return ({
+          a: 123,
+          b: ""
+      } as Record<string, number | string>)[id]
+    }
+
+    function grault(id: string) {
+      return ({
+          a: 123,
+          b: ""
+      } as { [k: string]: string | number})[id]
+    }
+

tests/baselines/reference/indexedAccessWithFreshObjectLiteral.js

@@ -0,0 +1,105 @@
+//// [indexedAccessWithFreshObjectLiteral.ts]
+function foo (id: string) {
+  return {
+      a: 1,
+      b: "",
+      c: true
+  }[id]
+}
+
+function bar (id: 'a' | 'b') {
+  return {
+      a: 1,
+      b: "",
+      c: false
+  }[id]
+}
+
+function baz (id: '1' | '2') {
+  return {
+      1: 1,
+      2: "",
+      3: false
+  }[id]
+}
+
+function qux (id: 1 | 2) {
+  return {
+      1: 1,
+      2: "",
+      3: false
+  }[id]
+}
+
+function quux (id: 'a' | 'b' | 'z') {
+  return {
+      a: 1,
+      b: "",
+      c: false
+  }[id]
+}
+
+function corge(id: string) {
+  return ({
+      a: 123,
+      b: ""
+  } as Record<string, number | string>)[id]
+}
+
+function grault(id: string) {
+  return ({
+      a: 123,
+      b: ""
+  } as { [k: string]: string | number})[id]
+}
+
+
+//// [indexedAccessWithFreshObjectLiteral.js]
+"use strict";
+function foo(id) {
+    return {
+        a: 1,
+        b: "",
+        c: true
+    }[id];
+}
+function bar(id) {
+    return {
+        a: 1,
+        b: "",
+        c: false
+    }[id];
+}
+function baz(id) {
+    return {
+        1: 1,
+        2: "",
+        3: false
+    }[id];
+}
+function qux(id) {
+    return {
+        1: 1,
+        2: "",
+        3: false
+    }[id];
+}
+function quux(id) {
+    return {
+        a: 1,
+        b: "",
+        c: false
+    }[id];
+}
+function corge(id) {
+    return {
+        a: 123,
+        b: ""
+    }[id];
+}
+function grault(id) {
+    return {
+        a: 123,
+        b: ""
+    }[id];
+}

tests/baselines/reference/indexedAccessWithFreshObjectLiteral.symbols

@@ -0,0 +1,123 @@
+=== tests/cases/compiler/indexedAccessWithFreshObjectLiteral.ts ===
+function foo (id: string) {
+>foo : Symbol(foo, Decl(indexedAccessWithFreshObjectLiteral.ts, 0, 0))
+>id : Symbol(id, Decl(indexedAccessWithFreshObjectLiteral.ts, 0, 14))
+
+  return {
+      a: 1,
+>a : Symbol(a, Decl(indexedAccessWithFreshObjectLiteral.ts, 1, 10))
+
+      b: "",
+>b : Symbol(b, Decl(indexedAccessWithFreshObjectLiteral.ts, 2, 11))
+
+      c: true
+>c : Symbol(c, Decl(indexedAccessWithFreshObjectLiteral.ts, 3, 12))
+
+  }[id]
+>id : Symbol(id, Decl(indexedAccessWithFreshObjectLiteral.ts, 0, 14))
+}
+
+function bar (id: 'a' | 'b') {
+>bar : Symbol(bar, Decl(indexedAccessWithFreshObjectLiteral.ts, 6, 1))
+>id : Symbol(id, Decl(indexedAccessWithFreshObjectLiteral.ts, 8, 14))
+
+  return {
+      a: 1,
+>a : Symbol(a, Decl(indexedAccessWithFreshObjectLiteral.ts, 9, 10))
+
+      b: "",
+>b : Symbol(b, Decl(indexedAccessWithFreshObjectLiteral.ts, 10, 11))
+
+      c: false
+>c : Symbol(c, Decl(indexedAccessWithFreshObjectLiteral.ts, 11, 12))
+
+  }[id]
+>id : Symbol(id, Decl(indexedAccessWithFreshObjectLiteral.ts, 8, 14))
+}
+
+function baz (id: '1' | '2') {
+>baz : Symbol(baz, Decl(indexedAccessWithFreshObjectLiteral.ts, 14, 1))
+>id : Symbol(id, Decl(indexedAccessWithFreshObjectLiteral.ts, 16, 14))
+
+  return {
+      1: 1,
+>1 : Symbol(1, Decl(indexedAccessWithFreshObjectLiteral.ts, 17, 10))
+
+      2: "",
+>2 : Symbol(2, Decl(indexedAccessWithFreshObjectLiteral.ts, 18, 11))
+
+      3: false
+>3 : Symbol(3, Decl(indexedAccessWithFreshObjectLiteral.ts, 19, 12))
+
+  }[id]
+>id : Symbol(id, Decl(indexedAccessWithFreshObjectLiteral.ts, 16, 14))
+}
+
+function qux (id: 1 | 2) {
+>qux : Symbol(qux, Decl(indexedAccessWithFreshObjectLiteral.ts, 22, 1))
+>id : Symbol(id, Decl(indexedAccessWithFreshObjectLiteral.ts, 24, 14))
+
+  return {
+      1: 1,
+>1 : Symbol(1, Decl(indexedAccessWithFreshObjectLiteral.ts, 25, 10))
+
+      2: "",
+>2 : Symbol(2, Decl(indexedAccessWithFreshObjectLiteral.ts, 26, 11))
+
+      3: false
+>3 : Symbol(3, Decl(indexedAccessWithFreshObjectLiteral.ts, 27, 12))
+
+  }[id]
+>id : Symbol(id, Decl(indexedAccessWithFreshObjectLiteral.ts, 24, 14))
+}
+
+function quux (id: 'a' | 'b' | 'z') {
+>quux : Symbol(quux, Decl(indexedAccessWithFreshObjectLiteral.ts, 30, 1))
+>id : Symbol(id, Decl(indexedAccessWithFreshObjectLiteral.ts, 32, 15))
+
+  return {
+      a: 1,
+>a : Symbol(a, Decl(indexedAccessWithFreshObjectLiteral.ts, 33, 10))
+
+      b: "",
+>b : Symbol(b, Decl(indexedAccessWithFreshObjectLiteral.ts, 34, 11))
+
+      c: false
+>c : Symbol(c, Decl(indexedAccessWithFreshObjectLiteral.ts, 35, 12))
+
+  }[id]
+>id : Symbol(id, Decl(indexedAccessWithFreshObjectLiteral.ts, 32, 15))
+}
+
+function corge(id: string) {
+>corge : Symbol(corge, Decl(indexedAccessWithFreshObjectLiteral.ts, 38, 1))
+>id : Symbol(id, Decl(indexedAccessWithFreshObjectLiteral.ts, 40, 15))
+
+  return ({
+      a: 123,
+>a : Symbol(a, Decl(indexedAccessWithFreshObjectLiteral.ts, 41, 11))
+
+      b: ""
+>b : Symbol(b, Decl(indexedAccessWithFreshObjectLiteral.ts, 42, 13))
+
+  } as Record<string, number | string>)[id]
+>Record : Symbol(Record, Decl(lib.es5.d.ts, --, --))
+>id : Symbol(id, Decl(indexedAccessWithFreshObjectLiteral.ts, 40, 15))
+}
+
+function grault(id: string) {
+>grault : Symbol(grault, Decl(indexedAccessWithFreshObjectLiteral.ts, 45, 1))
+>id : Symbol(id, Decl(indexedAccessWithFreshObjectLiteral.ts, 47, 16))
+
+  return ({
+      a: 123,
+>a : Symbol(a, Decl(indexedAccessWithFreshObjectLiteral.ts, 48, 11))
+
+      b: ""
+>b : Symbol(b, Decl(indexedAccessWithFreshObjectLiteral.ts, 49, 13))
+
+  } as { [k: string]: string | number})[id]
+>k : Symbol(k, Decl(indexedAccessWithFreshObjectLiteral.ts, 51, 10))
+>id : Symbol(id, Decl(indexedAccessWithFreshObjectLiteral.ts, 47, 16))
+}
+