Fix duplicate "this" completion (microsoft#25900)

Andy · web-flow · commit bd600cfd50a6 · 2018-07-25T12:29:28.000-07:00
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -4670,7 +4670,7 @@ namespace ts {
                     }
                 }
                 // Use contextual parameter type if one is available
-                const type = declaration.symbol.escapedName === "this" ? getContextualThisParameterType(func) : getContextuallyTypedParameterType(declaration);
+                const type = declaration.symbol.escapedName === InternalSymbolName.This ? getContextualThisParameterType(func) : getContextuallyTypedParameterType(declaration);
                 if (type) {
                     return addOptionality(type, isOptional);
                 }
@@ -7488,7 +7488,7 @@ namespace ts {
                         const resolvedSymbol = resolveName(param, paramSymbol.escapedName, SymbolFlags.Value, undefined, undefined, /*isUse*/ false);
                         paramSymbol = resolvedSymbol!;
                     }
-                    if (i === 0 && paramSymbol.escapedName === "this") {
+                    if (i === 0 && paramSymbol.escapedName === InternalSymbolName.This) {
                         hasThisParameter = true;
                         thisParameter = param.symbol;
                     }
@@ -15373,7 +15373,7 @@ namespace ts {
                 const jsDocFunctionType = <JSDocFunctionType>jsdocType;
                 if (jsDocFunctionType.parameters.length > 0 &&
                     jsDocFunctionType.parameters[0].name &&
-                    (jsDocFunctionType.parameters[0].name as Identifier).escapedText === "this") {
+                    (jsDocFunctionType.parameters[0].name as Identifier).escapedText === InternalSymbolName.This) {
                     return getTypeFromTypeNode(jsDocFunctionType.parameters[0].type!);
                 }
             }
@@ -26797,6 +26797,7 @@ namespace ts {
 
             populateSymbols();
 
+            symbols.delete(InternalSymbolName.This); // Not a symbol, a keyword
             return symbolsToArray(symbols);
 
             function populateSymbols() {
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
@@ -3559,6 +3559,7 @@ namespace ts {
         Resolving = "__resolving__", // Indicator symbol used to mark partially resolved type aliases
         ExportEquals = "export=", // Export assignment symbol
         Default = "default", // Default export symbol (technically not wholly internal, but included here for usability)
+        This = "this",
     }
 
     /**
diff --git a/tests/baselines/reference/api/tsserverlibrary.d.ts b/tests/baselines/reference/api/tsserverlibrary.d.ts
@@ -2106,7 +2106,8 @@ declare namespace ts {
         Computed = "__computed",
         Resolving = "__resolving__",
         ExportEquals = "export=",
-        Default = "default"
+        Default = "default",
+        This = "this"
     }
     /**
      * This represents a string whose leading underscore have been escaped by adding extra leading underscores.
diff --git a/tests/baselines/reference/api/typescript.d.ts b/tests/baselines/reference/api/typescript.d.ts
@@ -2106,7 +2106,8 @@ declare namespace ts {
         Computed = "__computed",
         Resolving = "__resolving__",
         ExportEquals = "export=",
-        Default = "default"
+        Default = "default",
+        This = "this"
     }
     /**
      * This represents a string whose leading underscore have been escaped by adding extra leading underscores.
diff --git a/tests/cases/fourslash/completionsThisType.ts b/tests/cases/fourslash/completionsThisType.ts
@@ -9,21 +9,20 @@
 ////
 ////function f(this: { x: number }) { /*f*/ }
 
-goTo.marker("");
-
-verify.completionListContains("xyz", "(method) C.xyz(): any", "", "method", undefined, undefined, {
-    includeInsertTextCompletions: true,
-    insertText: "this.xyz",
-});
-
-verify.completionListContains("foo bar", '(property) C["foo bar"]: number', "", "property", undefined, undefined, {
-    includeInsertTextCompletions: true,
-    insertText: 'this["foo bar"]',
-});
-
-goTo.marker("f");
-
-verify.completionListContains("x", "(property) x: number", "", "property", undefined, undefined, {
-    includeInsertTextCompletions: true,
-    insertText: "this.x",
-});
+const preferences: FourSlashInterface.UserPreferences = { includeInsertTextCompletions: true };
+verify.completions(
+    {
+        marker: "",
+        includes: [
+            { name: "xyz", text: "(method) C.xyz(): any", kind: "method", insertText: "this.xyz" },
+            { name: "foo bar", text: '(property) C["foo bar"]: number', kind: "property", insertText: 'this["foo bar"]' },
+        ],
+        isNewIdentifierLocation: true,
+        preferences,
+    },
+    {
+        marker: "f",
+        includes: { name: "x", text: "(property) x: number", kind: "property", insertText: "this.x" },
+        preferences,
+    },
+);

Original file line number	Diff line number	Diff line change
`@@ -4670,7 +4670,7 @@ namespace ts {`
`4670`	`4670`	`}`
`4671`	`4671`	`}`
`4672`	`4672`	`// Use contextual parameter type if one is available`
`4673`		`- const type = declaration.symbol.escapedName === "this" ? getContextualThisParameterType(func) : getContextuallyTypedParameterType(declaration);`
	`4673`	`+ const type = declaration.symbol.escapedName === InternalSymbolName.This ? getContextualThisParameterType(func) : getContextuallyTypedParameterType(declaration);`
`4674`	`4674`	`if (type) {`
`4675`	`4675`	`return addOptionality(type, isOptional);`
`4676`	`4676`	`}`
`@@ -7488,7 +7488,7 @@ namespace ts {`
`7488`	`7488`	`const resolvedSymbol = resolveName(param, paramSymbol.escapedName, SymbolFlags.Value, undefined, undefined, /isUse/ false);`
`7489`	`7489`	`paramSymbol = resolvedSymbol!;`
`7490`	`7490`	`}`
`7491`		`- if (i === 0 && paramSymbol.escapedName === "this") {`
	`7491`	`+ if (i === 0 && paramSymbol.escapedName === InternalSymbolName.This) {`
`7492`	`7492`	`hasThisParameter = true;`
`7493`	`7493`	`thisParameter = param.symbol;`
`7494`	`7494`	`}`
`@@ -15373,7 +15373,7 @@ namespace ts {`
`15373`	`15373`	`const jsDocFunctionType = <JSDocFunctionType>jsdocType;`
`15374`	`15374`	`if (jsDocFunctionType.parameters.length > 0 &&`
`15375`	`15375`	`jsDocFunctionType.parameters[0].name &&`
`15376`		`- (jsDocFunctionType.parameters[0].name as Identifier).escapedText === "this") {`
	`15376`	`+ (jsDocFunctionType.parameters[0].name as Identifier).escapedText === InternalSymbolName.This) {`
`15377`	`15377`	`return getTypeFromTypeNode(jsDocFunctionType.parameters[0].type!);`
`15378`	`15378`	`}`
`15379`	`15379`	`}`
`@@ -26797,6 +26797,7 @@ namespace ts {`
`26797`	`26797`
`26798`	`26798`	`populateSymbols();`
`26799`	`26799`
	`26800`	`+ symbols.delete(InternalSymbolName.This); // Not a symbol, a keyword`
`26800`	`26801`	`return symbolsToArray(symbols);`
`26801`	`26802`
`26802`	`26803`	`function populateSymbols() {`
Original file line number	Diff line number	Diff line change
`@@ -3559,6 +3559,7 @@ namespace ts {`
`3559`	`3559`	`Resolving = "__resolving__", // Indicator symbol used to mark partially resolved type aliases`
`3560`	`3560`	`ExportEquals = "export=", // Export assignment symbol`
`3561`	`3561`	`Default = "default", // Default export symbol (technically not wholly internal, but included here for usability)`
	`3562`	`+ This = "this",`
`3562`	`3563`	`}`
`3563`	`3564`
`3564`	`3565`	`/**`