diff options
Diffstat (limited to 'src/compiler')
| -rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/Implicits.scala | 9 | ||||
| -rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/Infer.scala | 3 |
2 files changed, 11 insertions, 1 deletions
diff --git a/src/compiler/scala/tools/nsc/typechecker/Implicits.scala b/src/compiler/scala/tools/nsc/typechecker/Implicits.scala index 9657cea101..c4464010c1 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Implicits.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Implicits.scala @@ -459,7 +459,9 @@ self: Analyzer => if (traceImplicits) println("tvars = "+tvars+"/"+(tvars map (_.constr))) val targs = solvedTypes(tvars, undetParams, undetParams map varianceInType(pt), false, lubDepth(List(itree2.tpe, pt))) - checkBounds(itree2.pos, NoPrefix, NoSymbol, undetParams, targs, "inferred ") // #2421 + + // #2421: check that we correctly instantiated type parameters outside of the implicit tree: + checkBounds(itree2.pos, NoPrefix, NoSymbol, undetParams, targs, "inferred ") // filter out failures from type inference, don't want to remove them from undetParams! // we must be conservative in leaving type params in undetparams @@ -472,6 +474,11 @@ self: Analyzer => val subst = new TreeTypeSubstituter(okParams, okArgs) subst traverse itree2 + // #2421b: since type inference (which may have been performed during implicit search) + // does not check whether inferred arguments meet the bounds of the corresponding parameter (see note in solvedTypes), + // must check again here: + typed1(itree2, EXPRmode, wildPt) + val result = new SearchResult(itree2, subst) incCounter(foundImplicits) if (traceImplicits) println("RESULT = "+result) diff --git a/src/compiler/scala/tools/nsc/typechecker/Infer.scala b/src/compiler/scala/tools/nsc/typechecker/Infer.scala index 1397aa06eb..621b6dce11 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Infer.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Infer.scala @@ -159,6 +159,9 @@ trait Infer { if (!solve(tvars, tparams, variances, upper, depth)) { // no panic, it's good enough to just guess a solution, we'll find out // later whether it works. +// @M danger, Will Robinson! this means that you should never trust inferred type arguments! +// need to call checkBounds on the args/typars or type1 on the tree for the expression that results from type inference +// see e.g., #2421: implicit search had been ignoring this caveat // throw new DeferredNoInstance(() => // "no solution exists for constraints"+(tvars map boundsString)) } |