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DanielRosenwasserDanielRosenwasser
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Merge pull request microsoft#5607 from Microsoft/fixTypeApparentization
Only get the apparent type of a contextual type when needed
2 parents 75364b6 + b93394a commit 9c1796f

20 files changed

Lines changed: 518 additions & 5 deletions

‎src/compiler/checker.ts‎

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@@ -7058,7 +7058,7 @@ namespace ts {
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else if (operator === SyntaxKind.BarBarToken) {
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// When an || expression has a contextual type, the operands are contextually typed by that type. When an ||
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// expression has no contextual type, the right operand is contextually typed by the type of the left operand.
7061-
let type = getApparentTypeOfContextualType(binaryExpression);
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let type = getContextualType(binaryExpression);
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if (!type && node === binaryExpression.right) {
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type = checkExpression(binaryExpression.left);
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}
@@ -7173,7 +7173,7 @@ namespace ts {
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// In a contextually typed conditional expression, the true/false expressions are contextually typed by the same type.
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function getContextualTypeForConditionalOperand(node: Expression): Type {
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const conditional = <ConditionalExpression>node.parent;
7176-
return node === conditional.whenTrue || node === conditional.whenFalse ? getApparentTypeOfContextualType(conditional) : undefined;
7176+
return node === conditional.whenTrue || node === conditional.whenFalse ? getContextualType(conditional) : undefined;
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}
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71797179
function getContextualTypeForJsxExpression(expr: JsxExpression | JsxSpreadAttribute): Type {
@@ -7206,9 +7206,16 @@ namespace ts {
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/**
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* Woah! Do you really want to use this function?
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*
7209-
* Unless you're trying to get the *non-apparent* type for a value-literal type,
7209+
* Unless you're trying to get the *non-apparent* type for a
7210+
* value-literal type or you're authoring relevant portions of this algorithm,
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* you probably meant to use 'getApparentTypeOfContextualType'.
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* Otherwise this is slightly less useful.
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* Otherwise this may not be very useful.
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*
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* In cases where you *are* working on this function, you should understand
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* when it is appropriate to use 'getContextualType' and 'getApparentTypeOfContetxualType'.
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*
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* - Use 'getContextualType' when you are simply going to propagate the result to the expression.
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* - Use 'getApparentTypeOfContextualType' when you're going to need the members of the type.
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*
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* @param node the expression whose contextual type will be returned.
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* @returns the contextual type of an expression.
@@ -7252,7 +7259,7 @@ namespace ts {
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Debug.assert(parent.parent.kind === SyntaxKind.TemplateExpression);
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return getContextualTypeForSubstitutionExpression(<TemplateExpression>parent.parent, node);
72547261
case SyntaxKind.ParenthesizedExpression:
7255-
return getApparentTypeOfContextualType(<ParenthesizedExpression>parent);
7262+
return getContextualType(<ParenthesizedExpression>parent);
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case SyntaxKind.JsxExpression:
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case SyntaxKind.JsxSpreadAttribute:
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return getContextualTypeForJsxExpression(<JsxExpression>parent);

‎tests/baselines/reference/stringLiteralTypesAndLogicalOrExpressions01.js‎

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//// [stringLiteralTypesAndLogicalOrExpressions01.ts]
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declare function myRandBool(): boolean;
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let a: "foo" = "foo";
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let b = a || "foo";
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let c: "foo" = b;
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let d = b || "bar";
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let e: "foo" | "bar" = d;
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//// [stringLiteralTypesAndLogicalOrExpressions01.js]
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var a = "foo";
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var b = a || "foo";
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var c = b;
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var d = b || "bar";
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var e = d;
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//// [stringLiteralTypesAndLogicalOrExpressions01.d.ts]
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declare function myRandBool(): boolean;
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declare let a: "foo";
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declare let b: "foo";
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declare let c: "foo";
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declare let d: "foo" | "bar";
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declare let e: "foo" | "bar";

‎tests/baselines/reference/stringLiteralTypesAndLogicalOrExpressions01.symbols‎

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=== tests/cases/conformance/types/stringLiteral/stringLiteralTypesAndLogicalOrExpressions01.ts ===
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declare function myRandBool(): boolean;
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>myRandBool : Symbol(myRandBool, Decl(stringLiteralTypesAndLogicalOrExpressions01.ts, 0, 0))
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let a: "foo" = "foo";
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>a : Symbol(a, Decl(stringLiteralTypesAndLogicalOrExpressions01.ts, 3, 3))
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let b = a || "foo";
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>b : Symbol(b, Decl(stringLiteralTypesAndLogicalOrExpressions01.ts, 4, 3))
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>a : Symbol(a, Decl(stringLiteralTypesAndLogicalOrExpressions01.ts, 3, 3))
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let c: "foo" = b;
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>c : Symbol(c, Decl(stringLiteralTypesAndLogicalOrExpressions01.ts, 5, 3))
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>b : Symbol(b, Decl(stringLiteralTypesAndLogicalOrExpressions01.ts, 4, 3))
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let d = b || "bar";
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>d : Symbol(d, Decl(stringLiteralTypesAndLogicalOrExpressions01.ts, 6, 3))
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>b : Symbol(b, Decl(stringLiteralTypesAndLogicalOrExpressions01.ts, 4, 3))
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let e: "foo" | "bar" = d;
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>e : Symbol(e, Decl(stringLiteralTypesAndLogicalOrExpressions01.ts, 7, 3))
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>d : Symbol(d, Decl(stringLiteralTypesAndLogicalOrExpressions01.ts, 6, 3))
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‎tests/baselines/reference/stringLiteralTypesAndLogicalOrExpressions01.types‎

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=== tests/cases/conformance/types/stringLiteral/stringLiteralTypesAndLogicalOrExpressions01.ts ===
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declare function myRandBool(): boolean;
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>myRandBool : () => boolean
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let a: "foo" = "foo";
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>a : "foo"
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>"foo" : "foo"
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let b = a || "foo";
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>b : "foo"
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>a || "foo" : "foo"
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>a : "foo"
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>"foo" : "foo"
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let c: "foo" = b;
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>c : "foo"
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>b : "foo"
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let d = b || "bar";
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>d : "foo" | "bar"
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>b || "bar" : "foo" | "bar"
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>b : "foo"
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>"bar" : "bar"
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let e: "foo" | "bar" = d;
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>e : "foo" | "bar"
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>d : "foo" | "bar"
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‎tests/baselines/reference/stringLiteralTypesAndParenthesizedExpressions01.js‎

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//// [stringLiteralTypesAndParenthesizedExpressions01.ts]
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declare function myRandBool(): boolean;
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let a: "foo" = ("foo");
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let b: "foo" | "bar" = ("foo");
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let c: "foo" = (myRandBool ? "foo" : ("foo"));
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let d: "foo" | "bar" = (myRandBool ? "foo" : ("bar"));
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//// [stringLiteralTypesAndParenthesizedExpressions01.js]
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var a = ("foo");
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var b = ("foo");
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var c = (myRandBool ? "foo" : ("foo"));
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var d = (myRandBool ? "foo" : ("bar"));
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//// [stringLiteralTypesAndParenthesizedExpressions01.d.ts]
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declare function myRandBool(): boolean;
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declare let a: "foo";
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declare let b: "foo" | "bar";
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declare let c: "foo";
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declare let d: "foo" | "bar";

‎tests/baselines/reference/stringLiteralTypesAndParenthesizedExpressions01.symbols‎

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=== tests/cases/conformance/types/stringLiteral/stringLiteralTypesAndParenthesizedExpressions01.ts ===
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declare function myRandBool(): boolean;
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>myRandBool : Symbol(myRandBool, Decl(stringLiteralTypesAndParenthesizedExpressions01.ts, 0, 0))
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let a: "foo" = ("foo");
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>a : Symbol(a, Decl(stringLiteralTypesAndParenthesizedExpressions01.ts, 3, 3))
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let b: "foo" | "bar" = ("foo");
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>b : Symbol(b, Decl(stringLiteralTypesAndParenthesizedExpressions01.ts, 4, 3))
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let c: "foo" = (myRandBool ? "foo" : ("foo"));
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>c : Symbol(c, Decl(stringLiteralTypesAndParenthesizedExpressions01.ts, 5, 3))
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>myRandBool : Symbol(myRandBool, Decl(stringLiteralTypesAndParenthesizedExpressions01.ts, 0, 0))
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let d: "foo" | "bar" = (myRandBool ? "foo" : ("bar"));
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>d : Symbol(d, Decl(stringLiteralTypesAndParenthesizedExpressions01.ts, 6, 3))
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>myRandBool : Symbol(myRandBool, Decl(stringLiteralTypesAndParenthesizedExpressions01.ts, 0, 0))
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‎tests/baselines/reference/stringLiteralTypesAndParenthesizedExpressions01.types‎

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=== tests/cases/conformance/types/stringLiteral/stringLiteralTypesAndParenthesizedExpressions01.ts ===
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declare function myRandBool(): boolean;
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>myRandBool : () => boolean
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let a: "foo" = ("foo");
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>a : "foo"
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>("foo") : "foo"
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>"foo" : "foo"
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let b: "foo" | "bar" = ("foo");
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>b : "foo" | "bar"
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>("foo") : "foo"
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>"foo" : "foo"
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let c: "foo" = (myRandBool ? "foo" : ("foo"));
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>c : "foo"
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>(myRandBool ? "foo" : ("foo")) : "foo"
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>myRandBool ? "foo" : ("foo") : "foo"
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>myRandBool : () => boolean
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>"foo" : "foo"
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>("foo") : "foo"
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>"foo" : "foo"
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let d: "foo" | "bar" = (myRandBool ? "foo" : ("bar"));
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>d : "foo" | "bar"
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>(myRandBool ? "foo" : ("bar")) : "foo" | "bar"
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>myRandBool ? "foo" : ("bar") : "foo" | "bar"
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>myRandBool : () => boolean
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>"foo" : "foo"
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>("bar") : "bar"
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>"bar" : "bar"
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‎tests/baselines/reference/stringLiteralTypesAsTypeParameterConstraint01.js‎

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//// [stringLiteralTypesAsTypeParameterConstraint01.ts]
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function foo<T extends "foo">(f: (x: T) => T) {
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return f;
5+
}
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function bar<T extends "foo" | "bar">(f: (x: T) => T) {
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return f;
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}
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let f = foo(x => x);
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let fResult = f("foo");
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let g = foo((x => x));
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let gResult = g("foo");
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let h = bar(x => x);
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let hResult = h("foo");
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hResult = h("bar");
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//// [stringLiteralTypesAsTypeParameterConstraint01.js]
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function foo(f) {
23+
return f;
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}
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function bar(f) {
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return f;
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}
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var f = foo(function (x) { return x; });
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var fResult = f("foo");
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var g = foo((function (x) { return x; }));
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var gResult = g("foo");
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var h = bar(function (x) { return x; });
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var hResult = h("foo");
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hResult = h("bar");
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//// [stringLiteralTypesAsTypeParameterConstraint01.d.ts]
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declare function foo<T extends "foo">(f: (x: T) => T): (x: T) => T;
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declare function bar<T extends "foo" | "bar">(f: (x: T) => T): (x: T) => T;
40+
declare let f: (x: "foo") => "foo";
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declare let fResult: "foo";
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declare let g: (x: "foo") => "foo";
43+
declare let gResult: "foo";
44+
declare let h: (x: "foo" | "bar") => "foo" | "bar";
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declare let hResult: "foo" | "bar";
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//// [DtsFileErrors]
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tests/cases/conformance/types/stringLiteral/stringLiteralTypesAsTypeParameterConstraint01.d.ts(3,16): error TS2382: Specialized overload signature is not assignable to any non-specialized signature.
52+
tests/cases/conformance/types/stringLiteral/stringLiteralTypesAsTypeParameterConstraint01.d.ts(5,16): error TS2382: Specialized overload signature is not assignable to any non-specialized signature.
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==== tests/cases/conformance/types/stringLiteral/stringLiteralTypesAsTypeParameterConstraint01.d.ts (2 errors) ====
56+
declare function foo<T extends "foo">(f: (x: T) => T): (x: T) => T;
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declare function bar<T extends "foo" | "bar">(f: (x: T) => T): (x: T) => T;
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declare let f: (x: "foo") => "foo";
59+
~~~~~~~~~~~~~~~~~~~
60+
!!! error TS2382: Specialized overload signature is not assignable to any non-specialized signature.
61+
declare let fResult: "foo";
62+
declare let g: (x: "foo") => "foo";
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~~~~~~~~~~~~~~~~~~~
64+
!!! error TS2382: Specialized overload signature is not assignable to any non-specialized signature.
65+
declare let gResult: "foo";
66+
declare let h: (x: "foo" | "bar") => "foo" | "bar";
67+
declare let hResult: "foo" | "bar";
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‎tests/baselines/reference/stringLiteralTypesAsTypeParameterConstraint01.symbols‎

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=== tests/cases/conformance/types/stringLiteral/stringLiteralTypesAsTypeParameterConstraint01.ts ===
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function foo<T extends "foo">(f: (x: T) => T) {
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>foo : Symbol(foo, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 0, 0))
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>T : Symbol(T, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 1, 13))
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>f : Symbol(f, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 1, 30))
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>x : Symbol(x, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 1, 34))
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>T : Symbol(T, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 1, 13))
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>T : Symbol(T, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 1, 13))
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return f;
12+
>f : Symbol(f, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 1, 30))
13+
}
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function bar<T extends "foo" | "bar">(f: (x: T) => T) {
16+
>bar : Symbol(bar, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 3, 1))
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>T : Symbol(T, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 5, 13))
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>f : Symbol(f, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 5, 38))
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>x : Symbol(x, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 5, 42))
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>T : Symbol(T, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 5, 13))
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>T : Symbol(T, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 5, 13))
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return f;
24+
>f : Symbol(f, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 5, 38))
25+
}
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let f = foo(x => x);
28+
>f : Symbol(f, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 9, 3))
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>foo : Symbol(foo, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 0, 0))
30+
>x : Symbol(x, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 9, 12))
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>x : Symbol(x, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 9, 12))
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let fResult = f("foo");
34+
>fResult : Symbol(fResult, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 10, 3))
35+
>f : Symbol(f, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 9, 3))
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let g = foo((x => x));
38+
>g : Symbol(g, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 12, 3))
39+
>foo : Symbol(foo, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 0, 0))
40+
>x : Symbol(x, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 12, 13))
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>x : Symbol(x, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 12, 13))
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let gResult = g("foo");
44+
>gResult : Symbol(gResult, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 13, 3))
45+
>g : Symbol(g, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 12, 3))
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47+
let h = bar(x => x);
48+
>h : Symbol(h, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 15, 3))
49+
>bar : Symbol(bar, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 3, 1))
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>x : Symbol(x, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 15, 12))
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>x : Symbol(x, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 15, 12))
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let hResult = h("foo");
54+
>hResult : Symbol(hResult, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 16, 3))
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>h : Symbol(h, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 15, 3))
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hResult = h("bar");
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>hResult : Symbol(hResult, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 16, 3))
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>h : Symbol(h, Decl(stringLiteralTypesAsTypeParameterConstraint01.ts, 15, 3))
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