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Esben Sparre Andreasen
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JS: support explicit type arguments for Flow
1 parent 45a4026 commit c26ae26

16 files changed

+2560
-0
lines changed

‎javascript/extractor/src/com/semmle/jcorn/Parser.java‎

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@@ -1744,6 +1744,10 @@ protected Expression parseNew() {
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if (isOnOptionalChain(false, callee))
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this.raise(callee, "An optional chain may not be used in a `new` expression.");
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return parseNewArguments(startLoc, callee);
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}
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protected Expression parseNewArguments(Position startLoc, Expression callee) {
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List<Expression> arguments;
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if (this.eat(TokenType.parenL))
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arguments = this.parseExprList(TokenType.parenR, this.options.ecmaVersion() >= 8, false, null);

‎javascript/extractor/src/com/semmle/jcorn/flow/FlowParser.java‎

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@@ -15,6 +15,7 @@
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import com.semmle.jcorn.TokenType;
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import com.semmle.jcorn.TokenType.Properties;
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import com.semmle.jcorn.Whitespace;
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import com.semmle.js.ast.BinaryExpression;
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import com.semmle.js.ast.ExportDeclaration;
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import com.semmle.js.ast.ExportSpecifier;
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import com.semmle.js.ast.Expression;
@@ -23,12 +24,15 @@
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import com.semmle.js.ast.Identifier;
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import com.semmle.js.ast.ImportDeclaration;
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import com.semmle.js.ast.ImportSpecifier;
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import com.semmle.js.ast.Literal;
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import com.semmle.js.ast.MethodDefinition;
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import com.semmle.js.ast.Node;
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import com.semmle.js.ast.Position;
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import com.semmle.js.ast.SourceLocation;
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import com.semmle.js.ast.Statement;
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import com.semmle.js.ast.Token;
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import com.semmle.js.ast.UnaryExpression;
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import com.semmle.util.data.Pair;
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import com.semmle.util.exception.Exceptions;
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/**
@@ -1203,4 +1207,43 @@ protected boolean atGetterSetterName(PropertyInfo pi) {
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return super.atGetterSetterName(pi);
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}
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@Override
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protected Pair<Expression, Boolean> parseSubscript(final Expression base, Position startLoc, boolean noCalls) {
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if (!noCalls) {
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maybeFlowParseTypeParameterInstantiation(base, true);
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}
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return super.parseSubscript(base, startLoc, noCalls);
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}
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private void maybeFlowParseTypeParameterInstantiation(Expression left, boolean requireParenL) {
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if (flow() && this.isRelational("<")) {
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// Ambiguous case: `e1<e2>(e3)` is parsed differently as JS and Flow code:
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// JS: two relational comparisons: `e1 < e2 > e3`
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// Flow: a call `e1(e3)` with explicit type parameter `e2`
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// Heuristic: if the left operand of the `<` token is a primitive from a literal or unary/binary expression, then it probably isn't a call, as that would always crash
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left = left.stripParens();
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if (left instanceof Literal || left instanceof UnaryExpression || left instanceof BinaryExpression)
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return;
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// If it can be parsed as Flow, we use that, otherwise we parse it as JS
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State backup = new State();
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try {
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this.flowParseTypeParameterInstantiation();
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if (requireParenL && this.type != TokenType.parenL) {
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unexpected();
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}
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backup.commit();
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} catch (SyntaxError e) {
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Exceptions.ignore(e, "Backtracking parser.");
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backup.reset();
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}
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}
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}
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@Override
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protected Expression parseNewArguments(Position startLoc, Expression callee) {
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maybeFlowParseTypeParameterInstantiation(callee, false /* case: new e1<e2>e3 */);
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return super.parseNewArguments(startLoc, callee);
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}
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}

‎javascript/extractor/tests/flow/input/boundExplicitTypeParameters.js‎

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@@ -0,0 +1 @@
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var b = ::o.m<T>;

‎javascript/extractor/tests/flow/input/explicitTypeParameters.js‎

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@@ -0,0 +1,12 @@
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new K1<T1>();
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f1<T2>();
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const f2 = function*(): T3<T4> {
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yield* f3<T5>(x);
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}
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f4<T6>(v1);
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f5<_,_,_>();
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f6<
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|T7
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|T8
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|T9
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>();

‎javascript/extractor/tests/flow/input/explicitTypeParametersForArgumentlessConstructorCall.js‎

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@@ -0,0 +1 @@
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new K1<T1>;

‎javascript/extractor/tests/flow/input/notExplicitTypeParameters1.js‎

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1<2>(3);

‎javascript/extractor/tests/flow/input/notExplicitTypeParameters2.js‎

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f<g()>(h());

‎javascript/extractor/tests/flow/input/notExplicitTypeParameters3.js‎

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/x/<2>(3);

‎javascript/extractor/tests/flow/input/practicallyAmbigiousExplicitTypeParameters.js‎

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@@ -0,0 +1,3 @@
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if(!(0<(jd|0)&0>(Wc|0))){}
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g=(g|0)<(e|0)|(g|0)>(b|0)?e:g;
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if((I|0)<(D|0)|(N|0)>(P|0)|(M|0)<(F|0)|(L|0)>(H|0)){}

‎javascript/extractor/tests/flow/output/trap/boundExplicitTypeParameters.js.trap‎

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#10000=@"/boundExplicitTypeParameters.js;sourcefile"
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files(#10000,"/boundExplicitTypeParameters.js","boundExplicitTypeParameters","js",0)
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#10001=@"/;folder"
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folders(#10001,"/","")
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containerparent(#10001,#10000)
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#10002=@"loc,{#10000},0,0,0,0"
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locations_default(#10002,#10000,0,0,0,0)
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hasLocation(#10000,#10002)
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#20000=@"global_scope"
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scopes(#20000,0)
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#20001=@"script;{#10000},1,1"
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toplevels(#20001,0)
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#20002=@"loc,{#10000},1,1,1,1"
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locations_default(#20002,#10000,1,1,1,1)
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hasLocation(#20001,#20002)
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#20003=*
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jsParseErrors(#20003,#20001,"Error: Unexpected token","var b = ::o.m<T>;")
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#20004=@"loc,{#10000},1,17,1,17"
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locations_default(#20004,#10000,1,17,1,17)
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hasLocation(#20003,#20004)
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#20005=*
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lines(#20005,#20001,"var b = ::o.m<T>;","")
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#20006=@"loc,{#10000},1,1,1,17"
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locations_default(#20006,#10000,1,1,1,17)
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hasLocation(#20005,#20006)
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numlines(#20001,1,0,0)
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numlines(#10000,1,0,0)
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filetype(#10000,"javascript")

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