diff --git a/compiler/src/dotty/tools/dotc/typer/Inferencing.scala b/compiler/src/dotty/tools/dotc/typer/Inferencing.scala
index 007dce352af5..c59c47a5a92b 100644
--- a/compiler/src/dotty/tools/dotc/typer/Inferencing.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Inferencing.scala
@@ -43,7 +43,6 @@ object Inferencing {
     if (isFullyDefined(tp, ForceDegree.all)) tp
     else throw new Error(i"internal error: type of $what $tp is not fully defined, pos = $span") // !!! DEBUG
 
-
   /** Instantiate selected type variables `tvars` in type `tp` */
   def instantiateSelected(tp: Type, tvars: List[Type])(implicit ctx: Context): Unit =
     if (tvars.nonEmpty)
diff --git a/compiler/src/dotty/tools/dotc/typer/Inliner.scala b/compiler/src/dotty/tools/dotc/typer/Inliner.scala
index 70f6718de2da..a7087b51dbea 100644
--- a/compiler/src/dotty/tools/dotc/typer/Inliner.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Inliner.scala
@@ -18,7 +18,7 @@ import Names.{Name, TermName}
 import NameKinds.{InlineAccessorName, InlineBinderName, InlineScrutineeName}
 import ProtoTypes.selectionProto
 import SymDenotations.SymDenotation
-import Inferencing.fullyDefinedType
+import Inferencing.isFullyDefined
 import config.Printers.inlining
 import ErrorReporting.errorTree
 import dotty.tools.dotc.tastyreflect.ReflectionImpl
@@ -242,8 +242,10 @@ class Inliner(call: tpd.Tree, rhsToInline: tpd.Tree)(implicit ctx: Context) {
 
   inlining.println(i"-----------------------\nInlining $call\nWith RHS $rhsToInline")
 
-  // Make sure all type arguments to the call are fully determined
-  for (targ <- callTypeArgs) fullyDefinedType(targ.tpe, "inlined type argument", targ.span)
+  // Make sure all type arguments to the call are fully determined,
+  // but continue if that's not achievable (or else i7459.scala would crash).
+  for arg <- callTypeArgs do
+    isFullyDefined(arg.tpe, ForceDegree.all)
 
   /** A map from parameter names of the inlineable method to references of the actual arguments.
    *  For a type argument this is the full argument type.
@@ -316,9 +318,9 @@ class Inliner(call: tpd.Tree, rhsToInline: tpd.Tree)(implicit ctx: Context) {
 
   /** Populate `paramBinding` and `bindingsBuf` by matching parameters with
    *  corresponding arguments. `bindingbuf` will be further extended later by
-   *  proxies to this-references.
+   *  proxies to this-references. Issue an error if some arguments are missing.
    */
-  private def computeParamBindings(tp: Type, targs: List[Tree], argss: List[List[Tree]]): Unit = tp match {
+  private def computeParamBindings(tp: Type, targs: List[Tree], argss: List[List[Tree]]): Boolean = tp match
     case tp: PolyType =>
       tp.paramNames.lazyZip(targs).foreach { (name, arg) =>
         paramSpan(name) = arg.span
@@ -326,19 +328,22 @@ class Inliner(call: tpd.Tree, rhsToInline: tpd.Tree)(implicit ctx: Context) {
       }
       computeParamBindings(tp.resultType, Nil, argss)
     case tp: MethodType =>
-      assert(argss.nonEmpty, i"missing bindings: $tp in $call")
-      tp.paramNames.lazyZip(tp.paramInfos).lazyZip(argss.head).foreach { (name, paramtp, arg) =>
-        paramSpan(name) = arg.span
-        paramBinding(name) = arg.tpe.dealias match {
-          case _: SingletonType if isIdempotentPath(arg) => arg.tpe
-          case _ => paramBindingDef(name, paramtp, arg, bindingsBuf).symbol.termRef
+      if argss.isEmpty then
+        ctx.error(i"mising arguments for inline method $inlinedMethod", call.sourcePos)
+        false
+      else
+        tp.paramNames.lazyZip(tp.paramInfos).lazyZip(argss.head).foreach { (name, paramtp, arg) =>
+          paramSpan(name) = arg.span
+          paramBinding(name) = arg.tpe.dealias match {
+            case _: SingletonType if isIdempotentPath(arg) => arg.tpe
+            case _ => paramBindingDef(name, paramtp, arg, bindingsBuf).symbol.termRef
+          }
         }
-      }
-      computeParamBindings(tp.resultType, targs, argss.tail)
+        computeParamBindings(tp.resultType, targs, argss.tail)
     case _ =>
       assert(targs.isEmpty)
       assert(argss.isEmpty)
-  }
+      true
 
   // Compute val-definitions for all this-proxies and append them to `bindingsBuf`
   private def computeThisBindings() = {
@@ -447,7 +452,8 @@ class Inliner(call: tpd.Tree, rhsToInline: tpd.Tree)(implicit ctx: Context) {
       }
 
     // Compute bindings for all parameters, appending them to bindingsBuf
-    computeParamBindings(inlinedMethod.info, callTypeArgs, callValueArgss)
+    if !computeParamBindings(inlinedMethod.info, callTypeArgs, callValueArgss) then
+      return call
 
     // make sure prefix is executed if it is impure
     if (!isIdempotentExpr(inlineCallPrefix)) registerType(inlinedMethod.owner.thisType)
diff --git a/tests/neg/i7438.scala b/tests/neg/i7438.scala
new file mode 100644
index 000000000000..c9e74ae31f5a
--- /dev/null
+++ b/tests/neg/i7438.scala
@@ -0,0 +1,9 @@
+type Tr[+A]
+inline def (tr: Tr[A]) map[A, B](f: A => B): Tr[B] = ???
+
+def (d: Double) func: None.type => Some[Double] = ???
+
+def run[A](query: None.type => Some[A]): Some[A] = ???
+
+val noBug = run(3.14 func) map (x => x)
+val buggy = run(3.14 func map (x => x)) // error: missing parameter type
\ No newline at end of file
diff --git a/tests/neg/i7459.scala b/tests/neg/i7459.scala
new file mode 100644
index 000000000000..e7c99c7a670a
--- /dev/null
+++ b/tests/neg/i7459.scala
@@ -0,0 +1,63 @@
+object Foo {
+  inline def summon[T](x: T): T =  x match {
+    case t: T => t
+  }
+  println(summon)  // error
+}
+
+import scala.deriving._
+import scala.compiletime.erasedValue
+
+inline def summon[T](given t:T): T = t match {
+  case t: T => t
+}
+
+inline def summonAll[T <: Tuple]: List[Eq[_]] = inline erasedValue[T] match {
+  case _: Unit => Nil
+  case _: (t *: ts) => summon[Eq[t]] :: summonAll[ts]  // error
+}
+
+trait Eq[T] {
+  def eqv(x: T, y: T): Boolean
+}
+
+object Eq {
+  given Eq[Int] {
+    def eqv(x: Int, y: Int) = x == y
+  }
+
+  def check(elem: Eq[_])(x: Any, y: Any): Boolean =
+    elem.asInstanceOf[Eq[Any]].eqv(x, y)
+
+  def iterator[T](p: T) = p.asInstanceOf[Product].productIterator
+
+  def eqSum[T](s: Mirror.SumOf[T], elems: List[Eq[_]]): Eq[T] =
+    new Eq[T] {
+      def eqv(x: T, y: T): Boolean = {
+        val ordx = s.ordinal(x)
+        (s.ordinal(y) == ordx) && check(elems(ordx))(x, y)
+      }
+    }
+
+  def eqProduct[T](p: Mirror.ProductOf[T], elems: List[Eq[_]]): Eq[T] =
+    new Eq[T] {
+      def eqv(x: T, y: T): Boolean =
+        iterator(x).zip(iterator(y)).zip(elems.iterator).forall {
+          case ((x, y), elem) => check(elem)(x, y)
+        }
+    }
+
+  inline given derived[T](given m: Mirror.Of[T]): Eq[T] = {
+    val elemInstances = summonAll[m.MirroredElemTypes]
+    inline m match {
+      case s: Mirror.SumOf[T]     => eqSum(s, elemInstances)
+      case p: Mirror.ProductOf[T] => eqProduct(p, elemInstances)
+    }
+  }
+}
+
+
+enum Opt[+T] derives Eq {
+  case Sm(t: T)
+  case Nn
+}
\ No newline at end of file
diff --git a/tests/pos/matrixOps.scala b/tests/pos/matrixOps.scala
new file mode 100644
index 000000000000..1824bc5fbbbf
--- /dev/null
+++ b/tests/pos/matrixOps.scala
@@ -0,0 +1,17 @@
+object Test with
+
+  type Matrix = Array[Array[Double]]
+  type Vector = Array[Double]
+
+  given (m: Matrix)
+    def nRows = m.length
+    def nCols = m(0).length
+    def row(i: Int): Vector = m(i)
+    def col(j: Int): Vector = Array.tabulate(m.length)(i => m(i)(j))
+
+  def pairwise(m: Matrix) =
+    for
+      i <- 0 until m.nRows
+      j <- 0 until m.nCols
+    yield
+      m.row(i).zip(m.row(j)).map(_ - _).sum