Check this params when comparing pseudotype signatures to type signatures (#4062)

Author: weswigham

internal/checker/pseudotypenodebuilder.go

@@ -450,22 +450,10 @@ func (b *NodeBuilderImpl) pseudoTypeEquivalentToType(t *pseudochecker.PseudoType
 					// Target property type doesn't have a single call signature; can't validate
 					continue
 				}
-				if len(targetSig.parameters) != len(d.Parameters) {
-					if reportErrors {
-						b.ctx.tracker.ReportInferenceFallback(e.Name.Parent)
-					}
+				paramEq := b.pseudoParametersEquivalentToParameters(d.Parameters, targetSig, reportErrors, e.Name.Parent)
+				if !paramEq {
 					return false
 				}
-				for i, p := range d.Parameters {
-					targetParam := targetSig.parameters[i]
-					paramType := b.ch.getTypeOfParameter(targetParam)
-					if !b.pseudoTypeEquivalentToType(p.Type, paramType, p.Optional, false) {
-						if reportErrors {
-							b.ctx.tracker.ReportInferenceFallback(e.Name.Parent)
-						}
-						return false
-					}
-				}
 				targetPredicate := b.ch.getTypePredicateOfSignature(targetSig)
 				if targetPredicate != nil {
 					if !b.pseudoReturnTypeMatchesPredicate(d.ReturnType, targetPredicate) {
@@ -533,27 +521,9 @@ func (b *NodeBuilderImpl) pseudoTypeEquivalentToType(t *pseudochecker.PseudoType
 			}
 			return false
 		}
-		if len(targetSig.parameters) != len(pt.Parameters) {
-			if reportErrors {
-				b.ctx.tracker.ReportInferenceFallback(pt.Signature)
-			}
-			return false // TODO: spread tuple params may mess with this check
-		}
-		for i, p := range pt.Parameters {
-			targetParam := targetSig.parameters[i]
-			if p.Optional != b.ch.isOptionalParameter(targetParam.ValueDeclaration) {
-				if reportErrors {
-					b.ctx.tracker.ReportInferenceFallback(p.Name.Parent)
-				}
-				return false
-			}
-			paramType := b.ch.getTypeOfParameter(targetParam)
-			if !b.pseudoTypeEquivalentToType(p.Type, paramType, p.Optional, false) {
-				if reportErrors {
-					b.ctx.tracker.ReportInferenceFallback(p.Name.Parent)
-				}
-				return false
-			}
+		paramEq := b.pseudoParametersEquivalentToParameters(pt.Parameters, targetSig, reportErrors, pt.Signature)
+		if !paramEq {
+			return false
 		}
 		targetPredicate := b.ch.getTypePredicateOfSignature(targetSig)
 		if targetPredicate != nil {
@@ -578,6 +548,53 @@ func (b *NodeBuilderImpl) pseudoTypeEquivalentToType(t *pseudochecker.PseudoType
 	}
 }
 
+func (b *NodeBuilderImpl) pseudoParametersEquivalentToParameters(params []*pseudochecker.PseudoParameter, targetSig *Signature, reportErrors bool, nonParamErrorLocation *ast.Node) bool {
+	if targetSig.thisParameter != nil && len(params) == 0 {
+		if reportErrors {
+			b.ctx.tracker.ReportInferenceFallback(nonParamErrorLocation) // missing `this` param
+		}
+		return false
+	} else if targetSig.thisParameter != nil && ast.IsThisIdentifier(params[0].Name) {
+		targetParam := targetSig.thisParameter
+		paramType := b.ch.getTypeOfParameter(targetParam)
+		if !b.pseudoTypeEquivalentToType(params[0].Type, paramType, params[0].Optional, false) {
+			if reportErrors {
+				b.ctx.tracker.ReportInferenceFallback(params[0].Name.Parent)
+			}
+			return false
+		}
+		params = params[1:]
+	} else if targetSig.thisParameter != nil {
+		if reportErrors {
+			b.ctx.tracker.ReportInferenceFallback(nonParamErrorLocation)
+		}
+		return false
+	}
+	if len(targetSig.parameters) != len(params) {
+		if reportErrors {
+			b.ctx.tracker.ReportInferenceFallback(nonParamErrorLocation)
+		}
+		return false // TODO: spread tuple params may mess with this check
+	}
+	for i, p := range params {
+		targetParam := targetSig.parameters[i]
+		if p.Optional != b.ch.isOptionalParameter(targetParam.ValueDeclaration) {
+			if reportErrors {
+				b.ctx.tracker.ReportInferenceFallback(p.Name.Parent)
+			}
+			return false
+		}
+		paramType := b.ch.getTypeOfParameter(targetParam)
+		if !b.pseudoTypeEquivalentToType(p.Type, paramType, p.Optional, false) {
+			if reportErrors {
+				b.ctx.tracker.ReportInferenceFallback(p.Name.Parent)
+			}
+			return false
+		}
+	}
+	return true
+}
+
 func isStructuralPseudoType(t *pseudochecker.PseudoType) bool {
 	switch t.Kind {
 	case pseudochecker.PseudoTypeKindObjectLiteral, pseudochecker.PseudoTypeKindTuple, pseudochecker.PseudoTypeKindSingleCallSignature:

testdata/baselines/reference/compiler/isolatedDeclarationsThisParameterWithCapturedGeneric.js

@@ -0,0 +1,23 @@
+//// [tests/cases/compiler/isolatedDeclarationsThisParameterWithCapturedGeneric.ts] ////
+
+//// [isolatedDeclarationsThisParameterWithCapturedGeneric.ts]
+export function fromProviders<T>() {
+  return {
+    tearDown(this: {state: T}): void {}
+  };
+}
+
+//// [isolatedDeclarationsThisParameterWithCapturedGeneric.js]
+export function fromProviders() {
+    return {
+        tearDown() { }
+    };
+}
+
+
+//// [isolatedDeclarationsThisParameterWithCapturedGeneric.d.ts]
+export declare function fromProviders<T>(): {
+    tearDown(this: {
+        state: T;
+    }): void;
+};

testdata/baselines/reference/compiler/isolatedDeclarationsThisParameterWithCapturedGeneric.symbols

@@ -0,0 +1,16 @@
+//// [tests/cases/compiler/isolatedDeclarationsThisParameterWithCapturedGeneric.ts] ////
+
+=== isolatedDeclarationsThisParameterWithCapturedGeneric.ts ===
+export function fromProviders<T>() {
+>fromProviders : Symbol(fromProviders, Decl(isolatedDeclarationsThisParameterWithCapturedGeneric.ts, 0, 0))
+>T : Symbol(T, Decl(isolatedDeclarationsThisParameterWithCapturedGeneric.ts, 0, 30))
+
+  return {
+    tearDown(this: {state: T}): void {}
+>tearDown : Symbol(tearDown, Decl(isolatedDeclarationsThisParameterWithCapturedGeneric.ts, 1, 10))
+>this : Symbol(this, Decl(isolatedDeclarationsThisParameterWithCapturedGeneric.ts, 2, 13))
+>state : Symbol(state, Decl(isolatedDeclarationsThisParameterWithCapturedGeneric.ts, 2, 20))
+>T : Symbol(T, Decl(isolatedDeclarationsThisParameterWithCapturedGeneric.ts, 0, 30))
+
+  };
+}

testdata/baselines/reference/compiler/isolatedDeclarationsThisParameterWithCapturedGeneric.types

@@ -0,0 +1,16 @@
+//// [tests/cases/compiler/isolatedDeclarationsThisParameterWithCapturedGeneric.ts] ////
+
+=== isolatedDeclarationsThisParameterWithCapturedGeneric.ts ===
+export function fromProviders<T>() {
+>fromProviders : <T>() => { tearDown(this: { state: T; }): void; }
+
+  return {
+>{    tearDown(this: {state: T}): void {}  } : { tearDown(this: { state: T; }): void; }
+
+    tearDown(this: {state: T}): void {}
+>tearDown : (this: { state: T; }) => void
+>this : { state: T; }
+>state : T
+
+  };
+}

testdata/tests/cases/compiler/isolatedDeclarationsThisParameterWithCapturedGeneric.ts

@@ -0,0 +1,7 @@
+// @declaration: true
+// @isolatedDeclarations: true
+export function fromProviders<T>() {
+  return {
+    tearDown(this: {state: T}): void {}
+  };
+}