AssemblyScript · jtenner · Jul 29, 2019 · Jul 30, 2019 · Jul 30, 2019 · Jul 30, 2019
diff --git a/src/common.ts b/src/common.ts
@@ -136,6 +136,7 @@ export namespace CommonSymbols {
   export const native = "native";
   export const indexof = "indexof";
   export const valueof = "valueof";
+  export const ReturnType = "ReturnType";
   // aliases
   export const null_ = "null";
   export const true_ = "true";

diff --git a/src/diagnosticMessages.generated.ts b/src/diagnosticMessages.generated.ts
@@ -136,6 +136,7 @@ export enum DiagnosticCode {
   Namespace_0_has_no_exported_member_1 = 2694,
   Required_type_parameters_may_not_follow_optional_type_parameters = 2706,
   Duplicate_property_0 = 2718,
+  Type_0_has_no_call_signatures = 2757,
   File_0_not_found = 6054,
   Numeric_separators_are_not_allowed_here = 6188,
   Multiple_consecutive_numeric_separators_are_not_permitted = 6189,
@@ -275,6 +276,7 @@ export function diagnosticCodeToString(code: DiagnosticCode): string {
     case 2694: return "Namespace '{0}' has no exported member '{1}'.";
     case 2706: return "Required type parameters may not follow optional type parameters.";
     case 2718: return "Duplicate property '{0}'.";
+    case 2757: return "Type '{0}' has no call signatures.";
     case 6054: return "File '{0}' not found.";
     case 6188: return "Numeric separators are not allowed here.";
     case 6189: return "Multiple consecutive numeric separators are not permitted.";

diff --git a/src/diagnosticMessages.json b/src/diagnosticMessages.json
@@ -130,6 +130,7 @@
   "Namespace '{0}' has no exported member '{1}'.": 2694,
   "Required type parameters may not follow optional type parameters.": 2706,
   "Duplicate property '{0}'.": 2718,
+  "Type '{0}' has no call signatures.": 2757,
 
   "File '{0}' not found.": 6054,
   "Numeric separators are not allowed here.": 6188,

diff --git a/src/program.ts b/src/program.ts
@@ -579,6 +579,12 @@ export class Program extends DiagnosticEmitter {
       this.makeNativeTypeDeclaration(CommonSymbols.valueof, CommonFlags.EXPORT | CommonFlags.GENERIC),
       DecoratorFlags.BUILTIN
     ));
+    this.nativeFile.add(CommonSymbols.ReturnType, new TypeDefinition(
+      CommonSymbols.ReturnType,
+      this.nativeFile,
+      this.makeNativeTypeDeclaration(CommonSymbols.ReturnType, CommonFlags.EXPORT | CommonFlags.GENERIC),
+      DecoratorFlags.BUILTIN
+    ));
     if (options.hasFeature(Feature.SIMD)) this.registerNativeType(CommonSymbols.v128, Type.v128);
 
     // register compiler hints

diff --git a/src/resolver.ts b/src/resolver.ts
@@ -273,6 +273,7 @@ export class Resolver extends DiagnosticEmitter {
           case CommonSymbols.native: return this.resolveBuiltinNativeType(node, ctxElement, ctxTypes, reportMode);
           case CommonSymbols.indexof: return this.resolveBuiltinIndexofType(node, ctxElement, ctxTypes, reportMode);
           case CommonSymbols.valueof: return this.resolveBuiltinValueofType(node, ctxElement, ctxTypes, reportMode);
+          case CommonSymbols.ReturnType: return this.resolveBuiltinReturnTypeType(node, ctxElement, ctxTypes, reportMode);
         }
       }
 
@@ -550,6 +551,41 @@ export class Resolver extends DiagnosticEmitter {
     return null;
   }
 
+  private resolveBuiltinReturnTypeType(
+    /** The type to resolve. */
+    node: NamedTypeNode,
+    /** Contextual element. */
+    ctxElement: Element,
+    /** Contextual types, i.e. `T`. */
+    ctxTypes: Map<string,Type> | null = null,
+    /** How to proceed with eventualy diagnostics. */
+    reportMode: ReportMode = ReportMode.REPORT
+  ): Type | null {
+    var typeArgumentNodes = node.typeArguments;
+    if (!(typeArgumentNodes && typeArgumentNodes.length == 1)) {
+      if (reportMode == ReportMode.REPORT) {
+        this.error(
+          DiagnosticCode.Expected_0_type_arguments_but_got_1,
+          node.range, "1", (typeArgumentNodes ? typeArgumentNodes.length : 1).toString(10)
+        );
+      }
+      return null;
+    }
+    var typeArgument = this.resolveType(typeArgumentNodes[0], ctxElement, ctxTypes, reportMode);
+    if (!typeArgument) return null;
+    var signatureReference = typeArgument.signatureReference;
+    if (!signatureReference) {
+      if (reportMode == ReportMode.REPORT) {
+        this.error(
+          DiagnosticCode.Type_0_has_no_call_signatures,
+          typeArgumentNodes[0].range, typeArgument.toString()
+        );
+      }
+      return null;
+    }
+    return signatureReference.returnType;
+  }
+
   /** Resolves a type name to the program element it refers to. */
   resolveTypeName(
     /** The type name to resolve. */

diff --git a/std/assembly/index.d.ts b/std/assembly/index.d.ts
@@ -886,7 +886,7 @@ declare type native<T> = T;
 declare type indexof<T extends unknown[]> = keyof T;
 /** Special type evaluating the indexed access value type. */
 declare type valueof<T extends unknown[]> = T[0];
-
+declare type ReturnType<T extends (...args: any) => any> = T extends (...args: any) => infer R ? R : any;
 /** Pseudo-class representing the backing class of integer types. */
 declare class _Integer {
   /** Smallest representable value. */

diff --git a/tests/compiler/ReturnType-error.json b/tests/compiler/ReturnType-error.json
@@ -0,0 +1,9 @@
+{
+  "asc_flags": [
+    "--runtime none"
+  ],
+  "stderr": [
+    "TS2757: Type 'i32' has no call signatures.",
+    "EOF"
+  ]
+}
diff --git a/tests/compiler/ReturnType-error.optimized.wat b/tests/compiler/ReturnType-error.optimized.wat
@@ -0,0 +1,8 @@
+(module
+ (type $FUNCSIG$v (func))
+ (memory $0 0)
+ (export "memory" (memory $0))
+ (func $null (; 0 ;) (type $FUNCSIG$v)
+  nop
+ )
+)
diff --git a/tests/compiler/ReturnType-error.ts b/tests/compiler/ReturnType-error.ts
@@ -0,0 +1,2 @@
+assert(isInteger<ReturnType<i32>>())
+ERROR("EOF");
diff --git a/tests/compiler/ReturnType-error.untouched.wat b/tests/compiler/ReturnType-error.untouched.wat
diff --git a/tests/compiler/ReturnType.json b/tests/compiler/ReturnType.json
@@ -0,0 +1,5 @@
+{
+  "asc_flags": [
+    "--runtime none"
+  ]
+}
diff --git a/tests/compiler/ReturnType.optimized.wat b/tests/compiler/ReturnType.optimized.wat
@@ -0,0 +1,8 @@
+(module
+ (type $FUNCSIG$v (func))
+ (memory $0 0)
+ (export "memory" (memory $0))
+ (func $null (; 0 ;) (type $FUNCSIG$v)
+  nop
+ )
+)
diff --git a/tests/compiler/ReturnType.ts b/tests/compiler/ReturnType.ts
@@ -0,0 +1,14 @@
+assert(isInteger<ReturnType<() => i8>>());
+assert(isSigned<ReturnType<() => i8>>());
+assert(sizeof<ReturnType<() => i8>>() == 1); // i32
+
+assert(isFloat<ReturnType<() => f64>>());
+assert(sizeof<ReturnType<() => f64>>() == 8);
+
+class SomeExample {
+  a: f64;
+  b: f64;
+}
+
+assert(isManaged<ReturnType<() => SomeExample>>());
+assert(offsetof<ReturnType<() => SomeExample>>() == 16);
diff --git a/tests/compiler/ReturnType.untouched.wat b/tests/compiler/ReturnType.untouched.wat
@@ -0,0 +1,9 @@
+(module
+ (type $FUNCSIG$v (func))
+ (memory $0 0)
+ (table $0 1 funcref)
+ (elem (i32.const 0) $null)
+ (export "memory" (memory $0))
+ (func $null (; 0 ;) (type $FUNCSIG$v)
+ )
+)
diff --git a/tests/compiler/binary.optimized.wat b/tests/compiler/binary.optimized.wat
@@ -29,8 +29,6 @@
   local.get $2
   i32.wrap_i64
   i32.const 0
-  i32.ne
-  i32.const 0
   local.get $1
   i32.const 2147483647
   i32.and

diff --git a/tests/compiler/std/libm.optimized.wat b/tests/compiler/std/libm.optimized.wat
@@ -2933,8 +2933,6 @@
   i32.const 1
   local.get $6
   i32.const 0
-  i32.ne
-  i32.const 0
   local.get $8
   i32.const 2146435072
   i32.eq
@@ -2946,8 +2944,6 @@
   i32.const 1
   local.get $19
   i32.const 0
-  i32.ne
-  i32.const 0
   local.get $4
   i32.const 2146435072
   i32.eq
@@ -7185,14 +7181,14 @@
       local.get $8
       i32.const -1021968384
       i32.eq
-      if
-       local.get $1
-       local.get $0
-       local.get $2
-       f32.sub
-       f32.le
-       br_if $folding-inner1
-      end
+      i32.const 0
+      local.get $1
+      local.get $0
+      local.get $2
+      f32.sub
+      f32.le
+      select
+      br_if $folding-inner1
      end
     end
     local.get $8

diff --git a/tests/compiler/std/math.optimized.wat b/tests/compiler/std/math.optimized.wat
@@ -6321,8 +6321,6 @@
   i32.const 1
   local.get $6
   i32.const 0
-  i32.ne
-  i32.const 0
   local.get $8
   i32.const 2146435072
   i32.eq
@@ -6334,8 +6332,6 @@
   i32.const 1
   local.get $19
   i32.const 0
-  i32.ne
-  i32.const 0
   local.get $4
   i32.const 2146435072
   i32.eq
@@ -7801,14 +7797,14 @@
       local.get $8
       i32.const -1021968384
       i32.eq
-      if
-       local.get $1
-       local.get $0
-       local.get $2
-       f32.sub
-       f32.le
-       br_if $folding-inner1
-      end
+      i32.const 0
+      local.get $1
+      local.get $0
+      local.get $2
+      f32.sub
+      f32.le
+      select
+      br_if $folding-inner1
      end
     end
     local.get $8

diff --git a/tests/compiler/std/operator-overloading.optimized.wat b/tests/compiler/std/operator-overloading.optimized.wat
@@ -284,8 +284,6 @@
   i32.const 1
   local.get $6
   i32.const 0
-  i32.ne
-  i32.const 0
   local.get $8
   i32.const 2146435072
   i32.eq
@@ -297,8 +295,6 @@
   i32.const 1
   local.get $19
   i32.const 0
-  i32.ne
-  i32.const 0
   local.get $4
   i32.const 2146435072
   i32.eq
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		assert(isInteger<ReturnType<i32>>())
		ERROR("EOF");