fix unnecessary Reference Check with property signature

src/compiler/checker.ts

@@ -1175,6 +1175,10 @@ namespace ts {
                         return true;
                     }
 
+                    if (isComputedPropertyName(current) && isPropertySignature(current.parent) && current.parent.name === current) {
+                        return true;
+                    }
+
                     const initializerOfProperty = current.parent &&
                         current.parent.kind === SyntaxKind.PropertyDeclaration &&
                         (<PropertyDeclaration>current.parent).initializer === current;

tests/baselines/reference/unnecessaryReferenceChecksWithPropertySignature.errors.txt

@@ -0,0 +1,27 @@
+tests/cases/compiler/unnecessaryReferenceChecksWithPropertySignature.ts(6,4): error TS2449: Class 'C' used before its declaration.
+tests/cases/compiler/unnecessaryReferenceChecksWithPropertySignature.ts(13,3): error TS1166: A computed property name in a class property declaration must refer to an expression whose type is a literal type or a 'unique symbol' type.
+tests/cases/compiler/unnecessaryReferenceChecksWithPropertySignature.ts(13,4): error TS2449: Class 'D' used before its declaration.
+
+
+==== tests/cases/compiler/unnecessaryReferenceChecksWithPropertySignature.ts (3 errors) ====
+    interface C {
+      [C.a](): void;
+      [C.b]: void;
+    }
+    class C {
+      [C.c] = 1;
+       ~
+!!! error TS2449: Class 'C' used before its declaration.
+      static readonly a = Symbol();
+      static readonly b = Symbol();
+      static readonly c = Symbol();
+    }
+
+    class D {
+      [D.a] = 0;
+      ~~~~~
+!!! error TS1166: A computed property name in a class property declaration must refer to an expression whose type is a literal type or a 'unique symbol' type.
+       ~
+!!! error TS2449: Class 'D' used before its declaration.
+      static a = "a";
+    }

tests/baselines/reference/unnecessaryReferenceChecksWithPropertySignature.js

@@ -0,0 +1,35 @@
+//// [unnecessaryReferenceChecksWithPropertySignature.ts]
+interface C {
+  [C.a](): void;
+  [C.b]: void;
+}
+class C {
+  [C.c] = 1;
+  static readonly a = Symbol();
+  static readonly b = Symbol();
+  static readonly c = Symbol();
+}
+
+class D {
+  [D.a] = 0;
+  static a = "a";
+}
+
+//// [unnecessaryReferenceChecksWithPropertySignature.js]
+var _a, _b;
+class C {
+    constructor() {
+        this[_a] = 1;
+    }
+}
+_a = C.c;
+C.a = Symbol();
+C.b = Symbol();
+C.c = Symbol();
+class D {
+    constructor() {
+        this[_b] = 0;
+    }
+}
+_b = D.a;
+D.a = "a";

tests/baselines/reference/unnecessaryReferenceChecksWithPropertySignature.symbols

@@ -0,0 +1,50 @@
+=== tests/cases/compiler/unnecessaryReferenceChecksWithPropertySignature.ts ===
+interface C {
+>C : Symbol(C, Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 0, 0), Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 3, 1))
+
+  [C.a](): void;
+>[C.a] : Symbol(C[C.a], Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 0, 13))
+>C.a : Symbol(C.a, Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 5, 12))
+>C : Symbol(C, Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 0, 0), Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 3, 1))
+>a : Symbol(C.a, Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 5, 12))
+
+  [C.b]: void;
+>[C.b] : Symbol(C[C.b], Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 1, 16))
+>C.b : Symbol(C.b, Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 6, 31))
+>C : Symbol(C, Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 0, 0), Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 3, 1))
+>b : Symbol(C.b, Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 6, 31))
+}
+class C {
+>C : Symbol(C, Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 0, 0), Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 3, 1))
+
+  [C.c] = 1;
+>[C.c] : Symbol(C[C.c], Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 4, 9))
+>C.c : Symbol(C.c, Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 7, 31))
+>C : Symbol(C, Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 0, 0), Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 3, 1))
+>c : Symbol(C.c, Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 7, 31))
+
+  static readonly a = Symbol();
+>a : Symbol(C.a, Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 5, 12))
+>Symbol : Symbol(Symbol, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+  static readonly b = Symbol();
+>b : Symbol(C.b, Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 6, 31))
+>Symbol : Symbol(Symbol, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+  static readonly c = Symbol();
+>c : Symbol(C.c, Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 7, 31))
+>Symbol : Symbol(Symbol, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+}
+
+class D {
+>D : Symbol(D, Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 9, 1))
+
+  [D.a] = 0;
+>[D.a] : Symbol(D[D.a], Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 11, 9))
+>D.a : Symbol(D.a, Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 12, 12))
+>D : Symbol(D, Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 9, 1))
+>a : Symbol(D.a, Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 12, 12))
+
+  static a = "a";
+>a : Symbol(D.a, Decl(unnecessaryReferenceChecksWithPropertySignature.ts, 12, 12))
+}

tests/baselines/reference/unnecessaryReferenceChecksWithPropertySignature.types

@@ -0,0 +1,56 @@
+=== tests/cases/compiler/unnecessaryReferenceChecksWithPropertySignature.ts ===
+interface C {
+>C : C
+
+  [C.a](): void;
+>[C.a] : () => void
+>C.a : unique symbol
+>C : typeof C
+>a : unique symbol
+
+  [C.b]: void;
+>[C.b] : void
+>C.b : unique symbol
+>C : typeof C
+>b : unique symbol
+}
+class C {
+>C : C
+
+  [C.c] = 1;
+>[C.c] : number
+>C.c : unique symbol
+>C : typeof C
+>c : unique symbol
+>1 : 1
+
+  static readonly a = Symbol();
+>a : unique symbol
+>Symbol() : unique symbol
+>Symbol : SymbolConstructor
+
+  static readonly b = Symbol();
+>b : unique symbol
+>Symbol() : unique symbol
+>Symbol : SymbolConstructor
+
+  static readonly c = Symbol();
+>c : unique symbol
+>Symbol() : unique symbol
+>Symbol : SymbolConstructor
+}
+
+class D {
+>D : D
+
+  [D.a] = 0;
+>[D.a] : number
+>D.a : string
+>D : typeof D
+>a : string
+>0 : 0
+
+  static a = "a";
+>a : string
+>"a" : "a"
+}

tests/cases/compiler/unnecessaryReferenceChecksWithPropertySignature.ts

@@ -0,0 +1,17 @@
+// @target: es6
+
+interface C {
+  [C.a](): void;
+  [C.b]: void;
+}
+class C {
+  [C.c] = 1;
+  static readonly a = Symbol();
+  static readonly b = Symbol();
+  static readonly c = Symbol();
+}
+
+class D {
+  [D.a] = 0;
+  static a = "a";
+}